diff --git a/docs/api-reference.md b/docs/api-reference.md
new file mode 100644
index 00000000..7866a898
--- /dev/null
+++ b/docs/api-reference.md
@@ -0,0 +1,90 @@
+# HTTP API Reference
+
+Codeman's HTTP API is a **stable contract** as of 1.0 — see
+[`versioning-policy.md`](versioning-policy.md) for the SemVer guarantee. This page
+defines the response envelope, status codes, error codes, versioning, and the SSE
+event channel.
+
+## Versioning
+
+- The stable, public surface is served under **`/api/v1/...`**. Pin external
+  clients to this prefix.
+- The unversioned **`/api/...`** paths are a permanent alias of the current
+  version (what the bundled web UI uses). They are kept working, but new external
+  integrations should use `/api/v1`.
+- Breaking changes to the contract ship under a new prefix (`/api/v2`); `/api/v1`
+  keeps its semantics. Additive changes (new endpoints, new optional fields, new
+  error codes) are non-breaking and may appear in a minor release.
+- The implementation rewrites `/api/v1/*` → `/api/*` at the server level
+  (`rewriteApiV1Url` in `src/web/server.ts`).
+
+## Response envelope
+
+Every JSON response uses one uniform envelope, applied centrally by a
+`preSerialization` hook (`src/web/server.ts`) — handlers return bare data and the
+hook wraps it:
+
+**Success** — HTTP `2xx`:
+
+```json
+{ "success": true, "data": <payload> }
+```
+
+`data` is the endpoint's payload (object, array, or value). Endpoints with no
+payload return `{ "success": true, "data": {} }`.
+
+**Error** — HTTP `4xx`/`5xx`:
+
+```json
+{ "success": false, "error": "human-readable message", "errorCode": "NOT_FOUND" }
+```
+
+`ApiResponse<T>` in `src/types/api.ts` is the canonical type.
+
+> Non-JSON endpoints are exempt from the envelope: `GET /api/sessions/:id/file-raw`,
+> `GET /api/sessions/:id/tail-file` (SSE), `GET /api/download`,
+> `GET /api/screenshots/:name`, `GET /q/:code` (QR redirect), and the
+> `GET /ws/sessions/:id/terminal` WebSocket upgrade.
+
+## Error codes → HTTP status
+
+The single source of truth is `ErrorStatus` / `httpStatusForErrorCode()` in
+`src/types/api.ts`. Clients should branch on `errorCode` (stable) and may rely on
+the HTTP status.
+
+| `errorCode` | HTTP | Meaning |
+|-------------|------|---------|
+| `INVALID_INPUT` | 400 | Malformed request / failed validation |
+| `UNAUTHORIZED` | 401 | Authentication required or failed |
+| `NOT_FOUND` | 404 | Resource does not exist |
+| `SESSION_BUSY` | 409 | Session is busy |
+| `CONFLICT` | 409 | Conflicts with current state (e.g. already running) |
+| `ALREADY_EXISTS` | 409 | Resource already exists |
+| `OPERATION_FAILED` | 422 | Well-formed but could not be completed |
+| `RATE_LIMITED` | 429 | Too many requests |
+| `INTERNAL_ERROR` | 500 | Unexpected server error |
+
+Adding a new error code is non-breaking; removing or renaming one is a major change.
+
+## Authentication
+
+Optional HTTP Basic (`CODEMAN_USERNAME`/`CODEMAN_PASSWORD`) → opaque
+`codeman_session` cookie. When enabled, unauthenticated requests get
+`401 UNAUTHORIZED`; rate-limited requests get `429 RATE_LIMITED`. See
+[`security-architecture.md`](security-architecture.md).
+
+## SSE event channel
+
+`GET /api/events` is a Server-Sent Events stream (`text/event-stream`); each
+message is `event: <name>` + `data: <json>`. The event-name registry
+(`src/web/sse-events.ts`, mirrored in `src/web/public/constants.js`) is part of
+the stable contract — event names are not renamed without a major bump. An
+optional `?sessions=<id,...>` filter suppresses only the high-volume terminal
+stream; lifecycle/metadata events are delivered to all clients regardless.
+
+## Consuming from JavaScript
+
+The bundled frontend reads responses through `_apiJson()`
+(`src/web/public/api-client.js`), which unwraps `{success:true,data}` → `data` and
+returns `null` on a non-2xx / `{success:false}` response. External clients should
+do the same: check the HTTP status (or `body.success`), then read `body.data`.
diff --git a/docs/versioning-policy.md b/docs/versioning-policy.md
index 14269891..01a72d49 100644
--- a/docs/versioning-policy.md
+++ b/docs/versioning-policy.md
@@ -8,9 +8,9 @@ surfaces are covered by SemVer and which are explicitly not. It exists because
 "1.0" is a commitment to stability, and an undocumented public surface invites
 incompatible client assumptions we would then be pressured to keep.
 
-> **Status:** draft for the 1.0 cut. The central decision below — that the HTTP/SSE
-> API is *not* SemVer-covered — should be confirmed by the maintainer before 1.0,
-> since it determines whether a number of in-flight cleanups are "breaking."
+> **Status:** finalized for the 1.0 cut. The HTTP/SSE API **is** part of the stable
+> surface — served under `/api/v1` with a uniform response envelope and
+> conventional HTTP status codes. See [`api-reference.md`](api-reference.md).
 
 ## What SemVer covers (the public, stable surface)
 
@@ -19,9 +19,10 @@ A **MAJOR** bump is required to break any of these after 1.0:
 1. **The CLI.** Command names, documented flags, and their behavior for
    `codeman <command>` (published to npm as `aicodeman`; invoked as `codeman`).
    This is the package's actual public entry point (`bin`).
-   - *Note:* the npm package name vs. invoked command name (`aicodeman` vs
-     `codeman`) is a known inconsistency to resolve **before** 1.0 — renaming
-     either after 1.0 is itself a breaking change.
+   - The package is published to npm as `aicodeman` and installs **both** the
+     `aicodeman` and `codeman` commands (`bin` aliases); `codeman` is the
+     canonical command used throughout the docs. Renaming either after 1.0 is a
+     breaking change.
 2. **The published `xterm-zerolag-input` library**, but on **its own version
    line** — it is versioned and released independently of the Codeman app. Its
    1.0 status is a separate decision; the Codeman app reaching 1.0 does *not*
@@ -31,26 +32,26 @@ A **MAJOR** bump is required to break any of these after 1.0:
    `CODEMAN_INSTANCE`, `CODEMAN_ALLOWED_HOSTS`, `CODEMAN_DATA_DIR`,
    `CODEMAN_TMUX_SOCKET`, and the `--host` / `--port` / `--https` CLI flags.
    Removing or changing the meaning of one of these is breaking.
+4. **The HTTP API and SSE event channel**, served under **`/api/v1`** with the
+   uniform `{success:true,data}` / `{success:false,error,errorCode}` envelope and
+   conventional HTTP status codes. Endpoint paths, the response envelope, error
+   `errorCode` values, and SSE event names are stable — see
+   [`api-reference.md`](api-reference.md). *Additive* changes (new endpoints, new
+   optional fields, new error codes, new SSE events) are non-breaking; breaking
+   changes ship under a new prefix (`/api/v2`). The unversioned `/api/...` alias
+   is kept working for the bundled UI.
 
 ## What SemVer does NOT cover (internal surfaces — may change in any release)
 
 These may change in a **MINOR** (or even PATCH) release without a MAJOR bump:
 
-1. **The HTTP API and SSE event registry** (`/api/...`, the ~120 SSE event
-   types). This is an **internal protocol between the server and its own bundled
-   web frontend**, not a published client API. There is no OpenAPI spec, no
-   published client, and no versioned `/api/v1` namespace. If you script against
-   these endpoints, **pin to an exact Codeman version** — they can change between
-   minors (response shapes, status codes, event names). Standardizing the error
-   envelope and HTTP status codes is explicitly reserved as a non-breaking
-   internal change under this policy.
-2. **The `~/.codeman/` state file formats** (`state.json`, `settings.json`,
+1. **The `~/.codeman/` state file formats** (`state.json`, `settings.json`,
    `mux-sessions.json`, etc.). We make a **best-effort** to migrate existing data
    forward (and have done so across renames), but the on-disk schema is not a
    stable contract — do not write tooling that depends on its exact shape.
-3. **Internal TypeScript modules.** The npm package is CLI-only; `import`ing it
+2. **Internal TypeScript modules.** The npm package is CLI-only; `import`ing it
    programmatically is not supported (there is no stable library entry point).
-4. **Experimental / opt-in features**, regardless of the app's version:
+3. **Experimental / opt-in features**, regardless of the app's version:
    Gesture Control (beta), Agent Teams
    (`CLAUDE_CODE_EXPERIMENTAL_AGENT_TEAMS=1`), and anything labeled experimental
    in the UI or docs. These may change or be removed at any time.
diff --git a/src/types/api.ts b/src/types/api.ts
index 6961b315..9c98d2d3 100644
--- a/src/types/api.ts
+++ b/src/types/api.ts
@@ -25,12 +25,18 @@ export enum ApiErrorCode {
   NOT_FOUND = 'NOT_FOUND',
   /** Invalid input provided */
   INVALID_INPUT = 'INVALID_INPUT',
+  /** Authentication required or failed */
+  UNAUTHORIZED = 'UNAUTHORIZED',
   /** Session is currently busy */
   SESSION_BUSY = 'SESSION_BUSY',
-  /** Operation failed */
-  OPERATION_FAILED = 'OPERATION_FAILED',
+  /** Request conflicts with current state (e.g. already running) */
+  CONFLICT = 'CONFLICT',
   /** Resource already exists */
   ALREADY_EXISTS = 'ALREADY_EXISTS',
+  /** Too many requests / rate limited */
+  RATE_LIMITED = 'RATE_LIMITED',
+  /** Operation could not be completed (well-formed but unprocessable) */
+  OPERATION_FAILED = 'OPERATION_FAILED',
   /** Internal server error */
   INTERNAL_ERROR = 'INTERNAL_ERROR',
 }
@@ -41,12 +47,37 @@ export enum ApiErrorCode {
 const ErrorMessages: Record<ApiErrorCode, string> = {
   [ApiErrorCode.NOT_FOUND]: 'The requested resource was not found',
   [ApiErrorCode.INVALID_INPUT]: 'Invalid input provided',
+  [ApiErrorCode.UNAUTHORIZED]: 'Authentication required',
   [ApiErrorCode.SESSION_BUSY]: 'Session is currently busy',
-  [ApiErrorCode.OPERATION_FAILED]: 'The operation failed',
+  [ApiErrorCode.CONFLICT]: 'Request conflicts with the current state',
   [ApiErrorCode.ALREADY_EXISTS]: 'Resource already exists',
+  [ApiErrorCode.RATE_LIMITED]: 'Too many requests',
+  [ApiErrorCode.OPERATION_FAILED]: 'The operation failed',
   [ApiErrorCode.INTERNAL_ERROR]: 'An internal error occurred',
 };
 
+/**
+ * Maps each API error code to its HTTP status. Single source of truth for the
+ * stable HTTP contract (see docs/api-reference.md). Applied centrally so every
+ * error response carries a conventional 4xx/5xx status, not 200.
+ */
+const ErrorStatus: Record<ApiErrorCode, number> = {
+  [ApiErrorCode.INVALID_INPUT]: 400,
+  [ApiErrorCode.UNAUTHORIZED]: 401,
+  [ApiErrorCode.NOT_FOUND]: 404,
+  [ApiErrorCode.SESSION_BUSY]: 409,
+  [ApiErrorCode.CONFLICT]: 409,
+  [ApiErrorCode.ALREADY_EXISTS]: 409,
+  [ApiErrorCode.OPERATION_FAILED]: 422,
+  [ApiErrorCode.RATE_LIMITED]: 429,
+  [ApiErrorCode.INTERNAL_ERROR]: 500,
+};
+
+/** HTTP status for an API error code (defaults to 400 for unknown codes). */
+export function httpStatusForErrorCode(code: ApiErrorCode): number {
+  return ErrorStatus[code] ?? 400;
+}
+
 /**
  * Hook event types triggered by Claude Code's hooks system
  */
diff --git a/src/web/public/api-client.js b/src/web/public/api-client.js
index e220a170..fea0d2b5 100644
--- a/src/web/public/api-client.js
+++ b/src/web/public/api-client.js
@@ -44,11 +44,20 @@ Object.assign(CodemanApp.prototype, {
   async _apiJson(path, opts = {}) {
     const res = await this._api(path, opts);
     if (!res || !res.ok) return null;
+    let body;
     try {
-      return await res.json();
+      body = await res.json();
     } catch {
       return null;
     }
+    // Uniform API envelope (stable HTTP contract): unwrap { success:true, data } → data;
+    // { success:false } → null (errors also surface as a non-ok HTTP status above).
+    // Legacy/bare bodies pass through unchanged.
+    if (body && typeof body === 'object') {
+      if (body.success === false) return null;
+      if (body.success === true && 'data' in body) return body.data;
+    }
+    return body;
   },
 
   /**
diff --git a/src/web/public/app.js b/src/web/public/app.js
index 03b2d218..19e21371 100644
--- a/src/web/public/app.js
+++ b/src/web/public/app.js
@@ -597,7 +597,7 @@ class CodemanApp {
     // Fetch tunnel status for header indicator (desktop only)
     this.loadTunnelStatus();
     // Share a single settings fetch between both consumers
-    const settingsPromise = fetch('/api/settings').then(r => r.ok ? r.json() : null).catch(() => null);
+    const settingsPromise = fetch('/api/settings').then(r => r.ok ? r.json() : null).then(env => env?.data ?? null).catch(() => null);
     this.loadQuickStartCases(null, settingsPromise);
     this._initRunMode();
     this.setupEventListeners();
@@ -1531,13 +1531,13 @@ class CodemanApp {
     try {
       // Source 1: Transcript JSONL (best quality — clean structured text from Claude)
       const res = await fetch(`/api/sessions/${this.activeSessionId}/last-response`);
-      const data = await res.json();
+      const data = (await res.json())?.data ?? {};
       let lastResponse = data.text || '';
 
       // Source 2: Terminal buffer fallback — strip ANSI, drop Claude CLI chrome
       if (!lastResponse) {
         const termRes = await fetch(`/api/sessions/${this.activeSessionId}/terminal`);
-        const termData = await termRes.json();
+        const termData = (await termRes.json())?.data ?? {};
         if (termData.terminalBuffer) {
           lastResponse = this._cleanTerminalBuffer(termData.terminalBuffer);
         }
@@ -1567,7 +1567,7 @@ class CodemanApp {
     if (moreBtn) moreBtn.textContent = '...';
     try {
       const res = await fetch(`/api/sessions/${this.activeSessionId}/last-response?context=full`);
-      const data = await res.json();
+      const data = (await res.json())?.data ?? {};
       const messages = data.messages || [];
       const body = document.getElementById('responseViewerBody');
       const title = document.getElementById('responseViewerTitle');
@@ -1618,7 +1618,7 @@ class CodemanApp {
     if (this._isLoadingBuffer) return;
     try {
       const res = await fetch(`/api/sessions/${this.activeSessionId}/terminal?tail=${TERMINAL_TAIL_SIZE}`);
-      const data = await res.json();
+      const data = (await res.json())?.data ?? {};
       if (data.terminalBuffer) {
         this.terminal.clear();
         this.terminal.reset();
@@ -1648,7 +1648,7 @@ class CodemanApp {
       // Fetch buffer, clear terminal, write buffer, resize (no Ctrl+L needed)
       try {
         const res = await fetch(`/api/sessions/${data.id}/terminal`);
-        const termData = await res.json();
+        const termData = (await res.json())?.data ?? {};
 
         this.terminal.clear();
         this.terminal.reset();
@@ -2254,7 +2254,7 @@ class CodemanApp {
     try {
       const res = await fetch('/api/status');
       const data = await res.json();
-      this.handleInit(data);
+      this.handleInit(data?.data ?? {});
     } catch (err) {
       console.error('Failed to load state:', err);
     }
@@ -2938,7 +2938,7 @@ class CodemanApp {
       _crashDiag.log('FETCH_START');
       const res = await fetch(`/api/sessions/${sessionId}/terminal?tail=${TERMINAL_TAIL_SIZE}`);
       if (this._isStaleSelect(selectGen)) return;
-      const data = await res.json();
+      const data = (await res.json())?.data ?? {};
       _crashDiag.log(`FETCH_DONE: ${data.terminalBuffer ? (data.terminalBuffer.length/1024).toFixed(0) + 'KB' : 'empty'} truncated=${data.truncated}`);
 
       if (data.terminalBuffer) {
diff --git a/src/web/public/image-input.js b/src/web/public/image-input.js
index c50a6667..0402d62d 100644
--- a/src/web/public/image-input.js
+++ b/src/web/public/image-input.js
@@ -149,7 +149,7 @@ Object.assign(CodemanApp.prototype, {
     }
 
     const data = await resp.json();
-    return data.path;
+    return data.data.path;
   },
 
   // Decode an image File through the browser and re-encode it to a format the
diff --git a/src/web/public/orchestrator-panel.js b/src/web/public/orchestrator-panel.js
index c7f2f4b9..ddbd3e48 100644
--- a/src/web/public/orchestrator-panel.js
+++ b/src/web/public/orchestrator-panel.js
@@ -182,7 +182,7 @@ Object.assign(CodemanApp.prototype, {
         body: JSON.stringify({ goal, config }),
       });
       const data = await res.json();
-      if (data.ok) {
+      if (data.data?.ok) {
         this.orchestratorState = { state: 'planning', plan: null };
         this.showOrchestratorPanel();
         this.renderOrchestratorPanel();
@@ -259,8 +259,8 @@ Object.assign(CodemanApp.prototype, {
     try {
       const res = await fetch('/api/orchestrator/status');
       const data = await res.json();
-      if (data.ok) {
-        this.orchestratorState = data;
+      if (data.data?.ok) {
+        this.orchestratorState = data.data;
         this.renderOrchestratorPanel();
       }
     } catch (err) {
diff --git a/src/web/public/panels-ui.js b/src/web/public/panels-ui.js
index 440f5101..499bcf7f 100644
--- a/src/web/public/panels-ui.js
+++ b/src/web/public/panels-ui.js
@@ -251,7 +251,7 @@ Object.assign(CodemanApp.prototype, {
       const response = await fetch('/api/token-stats');
       const data = await response.json();
       if (data.success) {
-        this.renderTokenStats(data);
+        this.renderTokenStats(data.data);
         document.getElementById('tokenStatsModal').classList.add('active');
       } else {
         this.showToast('Failed to load token stats', 'error');
@@ -2881,7 +2881,7 @@ Object.assign(CodemanApp.prototype, {
     try {
       const res = await fetch('/api/mux-sessions');
       const data = await res.json();
-      this.muxSessions = data.sessions || [];
+      this.muxSessions = data.data?.sessions || [];
       this.renderMuxSessions();
     } catch (err) {
       console.error('Failed to load mux sessions:', err);
@@ -3109,8 +3109,8 @@ Object.assign(CodemanApp.prototype, {
       const res = await fetch('/api/mux-sessions/reconcile', { method: 'POST' });
       const data = await res.json();
 
-      if (data.dead && data.dead.length > 0) {
-        this.showToast(`Found ${data.dead.length} dead mux session(s)`, 'warning');
+      if (data.data?.dead && data.data.dead.length > 0) {
+        this.showToast(`Found ${data.data.dead.length} dead mux session(s)`, 'warning');
         await this.loadMuxSessions();
       } else {
         this.showToast('All mux sessions are alive', 'success');
@@ -3220,7 +3220,7 @@ Object.assign(CodemanApp.prototype, {
     try {
       const res = await fetch('/api/system/stats');
       const stats = await res.json();
-      this.updateSystemStatsDisplay(stats);
+      this.updateSystemStatsDisplay(stats.data);
     } catch (err) {
       // Silently fail - system stats are not critical
     }
diff --git a/src/web/public/ralph-panel.js b/src/web/public/ralph-panel.js
index dbd74afa..25898f4f 100644
--- a/src/web/public/ralph-panel.js
+++ b/src/web/public/ralph-panel.js
@@ -996,14 +996,14 @@ Object.assign(CodemanApp.prototype, {
         return;
       }
 
-      const history = data.history || [];
+      const history = data.data.history || [];
       if (history.length === 0) {
         this.showToast('No plan history available', 'info');
         return;
       }
 
       // Show history dropdown modal
-      this.showPlanHistoryModal(history, data.currentVersion);
+      this.showPlanHistoryModal(history, data.data.currentVersion);
     } catch (err) {
       this.showToast('Failed to load plan history: ' + err.message, 'error');
     }
diff --git a/src/web/public/ralph-wizard.js b/src/web/public/ralph-wizard.js
index b9bc6501..9e81420d 100644
--- a/src/web/public/ralph-wizard.js
+++ b/src/web/public/ralph-wizard.js
@@ -151,11 +151,11 @@ Object.assign(CodemanApp.prototype, {
       const res = await fetch(`/api/cases/${encodeURIComponent(caseName)}/fix-plan`);
       const data = await res.json();
 
-      if (data.success && data.exists && data.todos?.length > 0) {
+      if (data.success && data.data.exists && data.data.todos?.length > 0) {
         this.ralphWizardConfig.existingPlan = {
-          todos: data.todos,
-          stats: data.stats,
-          content: data.content,
+          todos: data.data.todos,
+          stats: data.data.stats,
+          content: data.data.content,
         };
         this.updateExistingPlanUI();
       } else {
@@ -1054,8 +1054,8 @@ Object.assign(CodemanApp.prototype, {
         this.showToast(data.error || 'Failed to start', 'error');
         return;
       }
-      this.ralphClosedSessions.delete(data.sessionId);
-      await this.selectSession(data.sessionId);
+      this.ralphClosedSessions.delete(data.data.sessionId);
+      await this.selectSession(data.data.sessionId);
       this.showToast(`Ralph Loop started in ${config.caseName}`, 'success');
     } catch (err) {
       console.error('Failed to start Ralph loop:', err);
diff --git a/src/web/public/respawn-ui.js b/src/web/public/respawn-ui.js
index 8e605742..fbdb9fcd 100644
--- a/src/web/public/respawn-ui.js
+++ b/src/web/public/respawn-ui.js
@@ -1041,7 +1041,7 @@ Object.assign(CodemanApp.prototype, {
         return;
       }
 
-      this.runSummaryData = data.summary;
+      this.runSummaryData = data.data.summary;
       this.renderRunSummary();
     } catch (err) {
       console.error('Failed to load run summary:', err);
diff --git a/src/web/public/session-ui.js b/src/web/public/session-ui.js
index 33606a75..d4200a39 100644
--- a/src/web/public/session-ui.js
+++ b/src/web/public/session-ui.js
@@ -50,15 +50,15 @@ Object.assign(CodemanApp.prototype, {
       let lastUsedCase = null;
       try {
         const settings = settingsPromise ? await settingsPromise : await fetch('/api/settings').then(r => r.ok ? r.json() : null);
-        if (settings) {
-          lastUsedCase = settings.lastUsedCase || null;
+        if (settings && settings.data) {
+          lastUsedCase = settings.data.lastUsedCase || null;
         }
       } catch {
         // Ignore settings load errors
       }
 
       const res = await fetch('/api/cases');
-      const cases = await res.json();
+      const cases = (await res.json()).data;
       this.cases = cases;
       console.log('[loadQuickStartCases] Loaded cases:', cases.map(c => c.name), 'lastUsedCase:', lastUsedCase);
 
@@ -125,7 +125,7 @@ Object.assign(CodemanApp.prototype, {
   async updateDirDisplayForCase(caseName) {
     try {
       const res = await fetch(`/api/cases/${caseName}`);
-      const data = await res.json();
+      const data = (await res.json()).data;
       if (data.path) {
         document.getElementById('dirDisplay').textContent = data.path;
         document.getElementById('dirInput').value = data.path;
@@ -304,7 +304,7 @@ Object.assign(CodemanApp.prototype, {
     try {
       // Get case path first
       const caseRes = await fetch(`/api/cases/${caseName}`);
-      let caseData = await caseRes.json();
+      let caseData = (await caseRes.json()).data;
 
       // Create the case if it doesn't exist
       if (!caseData.path) {
@@ -373,7 +373,7 @@ Object.assign(CodemanApp.prototype, {
       const sessionIds = [];
       for (const result of createResults) {
         if (!result.success) throw new Error(result.error);
-        sessionIds.push(result.session.id);
+        sessionIds.push(result.data.session.id);
       }
       firstSessionId = sessionIds[0];
 
@@ -452,7 +452,7 @@ Object.assign(CodemanApp.prototype, {
     try {
       // Get the case path
       const caseRes = await fetch(`/api/cases/${caseName}`);
-      let caseData = await caseRes.json();
+      let caseData = (await caseRes.json()).data;
 
       // Create the case if it doesn't exist
       if (!caseData.path) {
@@ -501,7 +501,7 @@ Object.assign(CodemanApp.prototype, {
       const sessionIds = [];
       for (const result of createResults) {
         if (!result.success) throw new Error(result.error);
-        sessionIds.push(result.session.id);
+        sessionIds.push(result.data.session.id);
       }
 
       // Step 2: Start all shells in parallel
@@ -545,7 +545,7 @@ Object.assign(CodemanApp.prototype, {
     try {
       // Check if OpenCode is available
       const statusRes = await fetch('/api/opencode/status');
-      const status = await statusRes.json();
+      const status = (await statusRes.json()).data;
       if (!status.available) {
         this.terminal.writeln('\x1b[1;31m OpenCode CLI not found.\x1b[0m');
         this.terminal.writeln('\x1b[90m Install with: curl -fsSL https://opencode.ai/install | bash\x1b[0m');
@@ -570,8 +570,8 @@ Object.assign(CodemanApp.prototype, {
 
       // Switch to the new session (don't pre-set activeSessionId — selectSession
       // early-returns when IDs match, skipping buffer load and sendResize)
-      if (data.sessionId) {
-        await this.selectSession(data.sessionId);
+      if (data.data.sessionId) {
+        await this.selectSession(data.data.sessionId);
       }
 
       this.terminal.focus();
@@ -789,8 +789,8 @@ Object.assign(CodemanApp.prototype, {
     try {
       const res = await fetch(`/api/sessions/${sessionId}/respawn/config`);
       const data = await res.json();
-      if (data.success && data.config) {
-        const c = data.config;
+      if (data.success && data.data && data.data.config) {
+        const c = data.data.config;
         document.getElementById('modalRespawnPrompt').value = c.updatePrompt || 'update all the docs and CLAUDE.md';
         document.getElementById('modalRespawnSendClear').checked = c.sendClear ?? true;
         document.getElementById('modalRespawnSendInit').checked = c.sendInit ?? true;
diff --git a/src/web/public/settings-ui.js b/src/web/public/settings-ui.js
index 06ff4560..43b45058 100644
--- a/src/web/public/settings-ui.js
+++ b/src/web/public/settings-ui.js
@@ -185,9 +185,9 @@ Object.assign(CodemanApp.prototype, {
     try {
       // Get VAPID public key from server
       const keyData = await this._apiJson('/api/push/vapid-key');
-      if (!keyData?.success) throw new Error('Failed to get VAPID key');
+      if (!keyData) throw new Error('Failed to get VAPID key');
 
-      const applicationServerKey = urlBase64ToUint8Array(keyData.data.publicKey);
+      const applicationServerKey = urlBase64ToUint8Array(keyData.publicKey);
       const subscription = await this._swRegistration.pushManager.subscribe({
         userVisibleOnly: true,
         applicationServerKey,
@@ -204,11 +204,11 @@ Object.assign(CodemanApp.prototype, {
           pushPreferences: this._buildPushPreferences(),
         },
       });
-      if (!data?.success) throw new Error('Failed to register subscription');
+      if (!data) throw new Error('Failed to register subscription');
 
       this._pushSubscription = subscription;
-      this._pushSubscriptionId = data.data.id;
-      localStorage.setItem('codeman-push-subscription-id', data.data.id);
+      this._pushSubscriptionId = data.id;
+      localStorage.setItem('codeman-push-subscription-id', data.id);
       this._updatePushUI(true);
       this.showToast('Push notifications enabled', 'success');
     } catch (err) {
@@ -598,7 +598,10 @@ Object.assign(CodemanApp.prototype, {
       let data = null;
       try {
         const res = await fetch('/api/system/update/status');
-        if (res.ok) data = await res.json();
+        if (res.ok) {
+          const env = await res.json();
+          data = env && env.success === true ? env.data : env;
+        }
       } catch { /* server restarting — keep polling */ }
 
       if (!data) {
@@ -652,7 +655,8 @@ Object.assign(CodemanApp.prototype, {
   async loadTunnelStatus() {
     try {
       const res = await fetch('/api/tunnel/status');
-      const status = await res.json();
+      const env = await res.json();
+      const status = env?.success === true ? env.data : env;
       const active = status.running && status.url;
       this._tunnelUrl = active ? status.url : null;
       this._updateTunnelUrlDisplay(this._tunnelUrl);
@@ -721,7 +725,8 @@ Object.assign(CodemanApp.prototype, {
         if (!res.ok) throw new Error('Tunnel not running');
         return res.json();
       })
-      .then(data => {
+      .then(env => {
+        const data = env?.success === true ? env.data : env;
         const container = document.getElementById('tunnelQrContainer');
         if (container && data.svg) container.innerHTML = data.svg;
         // Show auth badge, countdown, and regenerate button when auth is enabled
@@ -754,7 +759,8 @@ Object.assign(CodemanApp.prototype, {
     // Fetch URL for display
     fetch('/api/tunnel/status')
       .then(r => r.json())
-      .then(status => {
+      .then(env => {
+        const status = env?.success === true ? env.data : env;
         const urlEl = document.getElementById('tunnelQrUrl');
         if (urlEl && status.url) {
           urlEl.textContent = status.url;
@@ -786,7 +792,8 @@ Object.assign(CodemanApp.prototype, {
   _refreshTunnelQrFromApi() {
     fetch('/api/tunnel/qr')
       .then(res => res.ok ? res.json() : null)
-      .then(data => {
+      .then(env => {
+        const data = env?.success === true ? env.data : env;
         if (!data?.svg) return;
         const container = document.getElementById('tunnelQrContainer');
         if (container) container.innerHTML = data.svg;
@@ -901,7 +908,8 @@ Object.assign(CodemanApp.prototype, {
     this._tunnelPollTimer = setTimeout(async () => {
       try {
         const res = await fetch('/api/tunnel/status');
-        const status = await res.json();
+        const env = await res.json();
+        const status = env?.success === true ? env.data : env;
         if (status.running && status.url) {
           // Tunnel is up — update UI
           this._dismissTunnelConnecting();
@@ -960,7 +968,7 @@ Object.assign(CodemanApp.prototype, {
       }
       fetch('/api/tunnel/qr')
         .then(r => { if (!r.ok) throw new Error(); return r.json(); })
-        .then(data => { if (data.svg) qrInner.innerHTML = data.svg; })
+        .then(env => { const data = env?.success === true ? env.data : env; if (data.svg) qrInner.innerHTML = data.svg; })
         .catch(() => { qrInner.innerHTML = '<div style="color:#999;font-size:11px;padding:20px">QR unavailable</div>'; });
     } else {
       clearTimeout(this._welcomeQrShrinkTimer);
@@ -1032,7 +1040,8 @@ Object.assign(CodemanApp.prototype, {
     // Fetch tunnel info
     try {
       const res = await fetch('/api/tunnel/info');
-      const info = await res.json();
+      const env = await res.json();
+      const info = env?.success === true ? env.data : env;
       this._renderTunnelPanel(info);
     } catch {
       const body = document.getElementById('tunnelPanelBody');
@@ -1166,7 +1175,8 @@ Object.assign(CodemanApp.prototype, {
       this.showToast('All sessions revoked', 'success');
       // Refresh panel
       const res = await fetch('/api/tunnel/info');
-      const info = await res.json();
+      const env = await res.json();
+      const info = env?.success === true ? env.data : env;
       this._renderTunnelPanel(info);
     } catch {
       this.showToast('Failed to revoke sessions', 'error');
@@ -1261,7 +1271,8 @@ Object.assign(CodemanApp.prototype, {
 
     try {
       const res = await fetch(`/api/session-lifecycle?${params}`);
-      const data = await res.json();
+      const env = await res.json();
+      const data = env?.success === true ? env.data : env;
       const tbody = document.getElementById('lifecycleTableBody');
       const empty = document.getElementById('lifecycleEmpty');
 
@@ -1850,7 +1861,7 @@ Object.assign(CodemanApp.prototype, {
 
   async loadAppSettingsFromServer(settingsPromise = null) {
     try {
-      const settings = settingsPromise ? await settingsPromise : await fetch('/api/settings').then(r => r.ok ? r.json() : null);
+      const settings = settingsPromise ? await settingsPromise : await fetch('/api/settings').then(r => r.ok ? r.json() : null).then(env => env?.success === true ? env.data : env);
       if (settings) {
         // Extract notification prefs before merging app settings
         const { notificationPreferences, voiceSettings, respawnPresets, runMode, ...appSettings } = settings;
@@ -1942,7 +1953,8 @@ Object.assign(CodemanApp.prototype, {
     try {
       const res = await fetch('/api/subagent-window-states');
       if (res.ok) {
-        states = await res.json();
+        const env = await res.json();
+        states = env?.success === true ? env.data : env;
         // Also update localStorage
         localStorage.setItem('codeman-subagent-window-states', JSON.stringify(states));
       }
@@ -2009,7 +2021,8 @@ Object.assign(CodemanApp.prototype, {
     try {
       const res = await fetch('/api/subagent-parents');
       if (res.ok) {
-        mapData = await res.json();
+        const env = await res.json();
+        mapData = env?.success === true ? env.data : env;
         // Update localStorage as cache
         localStorage.setItem('codeman-subagent-parents', JSON.stringify(mapData));
       }
diff --git a/src/web/public/terminal-ui.js b/src/web/public/terminal-ui.js
index dbe36b1f..7aae408e 100644
--- a/src/web/public/terminal-ui.js
+++ b/src/web/public/terminal-ui.js
@@ -868,7 +868,7 @@ Object.assign(CodemanApp.prototype, {
   async _fetchHistorySessions() {
     const res = await fetch('/api/history/sessions');
     const data = await res.json();
-    const sessions = data.sessions || [];
+    const sessions = data.data?.sessions || [];
     if (sessions.length === 0) return [];
 
     const byProject = new Map();
@@ -1046,7 +1046,7 @@ Object.assign(CodemanApp.prototype, {
       // Prefer already-loaded this.cases to avoid an extra request.
       const casesPromise = Array.isArray(this.cases) && this.cases.length > 0
         ? Promise.resolve(this.cases)
-        : fetch('/api/cases').then((r) => (r.ok ? r.json() : [])).catch(() => []);
+        : fetch('/api/cases').then((r) => (r.ok ? r.json() : null)).then((d) => d?.data || []).catch(() => []);
       const [allSessions, cases] = await Promise.all([
         this._fetchHistorySessions(30),
         casesPromise,
@@ -1173,8 +1173,8 @@ Object.assign(CodemanApp.prototype, {
       const url = `/api/history/sessions?projectKey=${encodeURIComponent(projectKey)}&offset=${offset}&limit=${limit}`;
       const res = await fetch(url);
       const data = await res.json();
-      const sessions = data.sessions || [];
-      state.total = typeof data.total === 'number' ? data.total : sessions.length + offset;
+      const sessions = data.data?.sessions || [];
+      state.total = typeof data.data?.total === 'number' ? data.data.total : sessions.length + offset;
 
       if (offset === 0 && sessions.length === 0) {
         const empty = document.createElement('div');
@@ -1261,7 +1261,7 @@ Object.assign(CodemanApp.prototype, {
       const createData = await createRes.json();
       if (!createData.success) throw new Error(createData.error);
 
-      const newSessionId = createData.session.id;
+      const newSessionId = createData.data.session.id;
 
       // Start interactive
       await fetch(`/api/sessions/${newSessionId}/interactive`, { method: 'POST' });
diff --git a/src/web/routes/case-routes.ts b/src/web/routes/case-routes.ts
index 06901ae7..48ab869f 100644
--- a/src/web/routes/case-routes.ts
+++ b/src/web/routes/case-routes.ts
@@ -262,7 +262,7 @@ export function registerCaseRoutes(app: FastifyInstance, ctx: EventPort & Config
     const fixPlanPath = join(casePath, '@fix_plan.md');
 
     if (!existsSync(fixPlanPath)) {
-      return { success: true, exists: false, content: null, todos: [] };
+      return { exists: false, content: null, todos: [] };
     }
 
     try {
@@ -339,7 +339,6 @@ export function registerCaseRoutes(app: FastifyInstance, ctx: EventPort & Config
       const stats = { total: todos.length, pending, inProgress, completed };
 
       return {
-        success: true,
         exists: true,
         content,
         todos,
diff --git a/src/web/routes/clipboard-routes.ts b/src/web/routes/clipboard-routes.ts
index f36b87b6..fe8b90be 100644
--- a/src/web/routes/clipboard-routes.ts
+++ b/src/web/routes/clipboard-routes.ts
@@ -19,6 +19,6 @@ export function registerClipboardRoutes(app: FastifyInstance, ctx: EventPort): v
       sessionId: body.sessionId ?? null,
       timestamp: Date.now(),
     });
-    return { success: true };
+    return {};
   });
 }
diff --git a/src/web/routes/hook-event-routes.ts b/src/web/routes/hook-event-routes.ts
index 471dea4a..ff83e9d2 100644
--- a/src/web/routes/hook-event-routes.ts
+++ b/src/web/routes/hook-event-routes.ts
@@ -66,6 +66,6 @@ export function registerHookEventRoutes(
       summaryTracker.recordHookEvent(event, safeData);
     }
 
-    return { success: true };
+    return {};
   });
 }
diff --git a/src/web/routes/mux-routes.ts b/src/web/routes/mux-routes.ts
index b1264ae3..14b93760 100644
--- a/src/web/routes/mux-routes.ts
+++ b/src/web/routes/mux-routes.ts
@@ -19,7 +19,7 @@ export function registerMuxRoutes(app: FastifyInstance, ctx: InfraPort): void {
   app.delete('/api/mux-sessions/:sessionId', async (req) => {
     const { sessionId } = req.params as { sessionId: string };
     const success = await ctx.mux.killSession(sessionId);
-    return { success };
+    return { killed: success };
   });
 
   app.post('/api/mux-sessions/reconcile', async () => {
@@ -29,11 +29,11 @@ export function registerMuxRoutes(app: FastifyInstance, ctx: InfraPort): void {
 
   app.post('/api/mux-sessions/stats/start', async () => {
     ctx.mux.startStatsCollection(STATS_COLLECTION_INTERVAL_MS);
-    return { success: true };
+    return {};
   });
 
   app.post('/api/mux-sessions/stats/stop', async () => {
     ctx.mux.stopStatsCollection();
-    return { success: true };
+    return {};
   });
 }
diff --git a/src/web/routes/push-routes.ts b/src/web/routes/push-routes.ts
index a0ac9e03..0fb27b93 100644
--- a/src/web/routes/push-routes.ts
+++ b/src/web/routes/push-routes.ts
@@ -35,7 +35,7 @@ export function registerPushRoutes(app: FastifyInstance, ctx: InfraPort): void {
     if (!updated) {
       return createErrorResponse(ApiErrorCode.NOT_FOUND, 'Subscription not found');
     }
-    return { success: true };
+    return {};
   });
 
   app.delete('/api/push/subscribe/:id', async (req) => {
@@ -44,6 +44,6 @@ export function registerPushRoutes(app: FastifyInstance, ctx: InfraPort): void {
     if (!removed) {
       return createErrorResponse(ApiErrorCode.NOT_FOUND, 'Subscription not found');
     }
-    return { success: true };
+    return {};
   });
 }
diff --git a/src/web/routes/ralph-routes.ts b/src/web/routes/ralph-routes.ts
index 9a9c6937..615858f4 100644
--- a/src/web/routes/ralph-routes.ts
+++ b/src/web/routes/ralph-routes.ts
@@ -101,7 +101,7 @@ export function registerRalphRoutes(
       state: session.ralphLoopState,
     });
 
-    return { success: true };
+    return {};
   });
 
   // Reset circuit breaker for Ralph tracker
@@ -110,7 +110,7 @@ export function registerRalphRoutes(
     const session = findSessionOrFail(ctx, id);
 
     session.ralphTracker.resetCircuitBreaker();
-    return { success: true };
+    return {};
   });
 
   // Get Ralph status block and circuit breaker state
diff --git a/src/web/routes/respawn-routes.ts b/src/web/routes/respawn-routes.ts
index 02bdd169..15749437 100644
--- a/src/web/routes/respawn-routes.ts
+++ b/src/web/routes/respawn-routes.ts
@@ -62,16 +62,16 @@ export function registerRespawnRoutes(
     const controller = ctx.respawnControllers.get(id);
 
     if (controller) {
-      return { success: true, config: controller.getConfig(), active: true };
+      return { config: controller.getConfig(), active: true };
     }
 
     // Return pre-saved config from mux-sessions.json
     const preConfig = ctx.mux.getSession(id)?.respawnConfig;
     if (preConfig) {
-      return { success: true, config: preConfig, active: false };
+      return { config: preConfig, active: false };
     }
 
-    return { success: true, config: null, active: false };
+    return { config: null, active: false };
   });
 
   // ═══════════════════════════════════════════════════════════════
@@ -114,7 +114,7 @@ export function registerRespawnRoutes(
 
     ctx.broadcast(SseEvent.RespawnStarted, { sessionId: id, status: controller.getStatus() });
 
-    return { success: true, status: controller.getStatus() };
+    return { status: controller.getStatus() };
   });
 
   // ========== Stop Respawn ==========
@@ -150,7 +150,7 @@ export function registerRespawnRoutes(
 
     ctx.broadcast(SseEvent.RespawnStopped, { sessionId: id });
 
-    return { success: true };
+    return {};
   });
 
   // ========== Update Respawn Config ==========
@@ -169,7 +169,7 @@ export function registerRespawnRoutes(
       ctx.saveRespawnConfig(id, controller.getConfig());
       ctx.persistSessionState(session);
       ctx.broadcast(SseEvent.RespawnConfigUpdated, { sessionId: id, config: controller.getConfig() });
-      return { success: true, config: controller.getConfig() };
+      return { config: controller.getConfig() };
     }
 
     // No controller running - save as pre-config for when respawn starts
@@ -206,7 +206,7 @@ export function registerRespawnRoutes(
     ctx.mux.updateRespawnConfig(id, merged);
     ctx.persistSessionState(session);
     ctx.broadcast(SseEvent.RespawnConfigUpdated, { sessionId: id, config: merged });
-    return { success: true, config: merged };
+    return { config: merged };
   });
 
   // ═══════════════════════════════════════════════════════════════
@@ -332,7 +332,6 @@ export function registerRespawnRoutes(
     ctx.broadcast(SseEvent.RespawnStarted, { sessionId: id, status: controller.getStatus() });
 
     return {
-      success: true,
       message: 'Respawn enabled on existing session',
       respawnStatus: controller.getStatus(),
     };
diff --git a/src/web/routes/scheduled-routes.ts b/src/web/routes/scheduled-routes.ts
index a219eefa..614f3824 100644
--- a/src/web/routes/scheduled-routes.ts
+++ b/src/web/routes/scheduled-routes.ts
@@ -15,7 +15,7 @@ export function registerScheduledRoutes(app: FastifyInstance, ctx: SessionPort &
     return Array.from(ctx.scheduledRuns.values());
   });
 
-  app.post('/api/scheduled', async (req): Promise<{ success: boolean; run: ScheduledRun } | ApiResponse<never>> => {
+  app.post('/api/scheduled', async (req): Promise<{ run: ScheduledRun } | ApiResponse<never>> => {
     const { prompt, workingDir, durationMinutes } = parseBody(ScheduledRunSchema, req.body, 'Invalid request body');
 
     // Validate workingDir exists and is a directory
@@ -31,7 +31,7 @@ export function registerScheduledRoutes(app: FastifyInstance, ctx: SessionPort &
     }
 
     const run = await ctx.startScheduledRun(prompt, workingDir || process.cwd(), durationMinutes ?? 60);
-    return { success: true, run };
+    return { run };
   });
 
   app.delete('/api/scheduled/:id', async (req) => {
@@ -43,7 +43,7 @@ export function registerScheduledRoutes(app: FastifyInstance, ctx: SessionPort &
     }
 
     await ctx.stopScheduledRun(id);
-    return { success: true };
+    return {};
   });
 
   app.get('/api/scheduled/:id', async (req) => {
diff --git a/src/web/routes/session-routes.ts b/src/web/routes/session-routes.ts
index 41be3668..362b50a5 100644
--- a/src/web/routes/session-routes.ts
+++ b/src/web/routes/session-routes.ts
@@ -16,7 +16,6 @@ import {
   createErrorResponse,
   getErrorMessage,
   type ApiResponse,
-  type QuickStartResponse,
   type SessionColor,
 } from '../../types.js';
 import { Session } from '../../session.js';
@@ -211,7 +210,7 @@ export function registerSessionRoutes(
       ctx.authSessions?.delete(sessionToken);
     }
     reply.clearCookie(AUTH_COOKIE_NAME, { path: '/' });
-    return { success: true };
+    return {};
   });
 
   // ═══════════════════════════════════════════════════════════════
@@ -349,7 +348,7 @@ export function registerSessionRoutes(
     // Avoids serializing 2-3MB of terminal+text buffers per session creation.
     const lightState = ctx.getSessionStateWithRespawn(session);
     ctx.broadcast(SseEvent.SessionCreated, lightState);
-    return { success: true, session: lightState };
+    return { session: lightState };
   });
 
   // ========== Rename Session ==========
@@ -364,7 +363,7 @@ export function registerSessionRoutes(
     // Also update the mux session name if applicable
     ctx.mux.updateSessionName(id, session.name);
     persistAndBroadcastSession(ctx, session);
-    return { success: true, name: session.name };
+    return { name: session.name };
   });
 
   // ========== Set Session Color ==========
@@ -381,12 +380,12 @@ export function registerSessionRoutes(
 
     session.setColor(body.color as SessionColor);
     persistAndBroadcastSession(ctx, session);
-    return { success: true, color: session.color };
+    return { color: session.color };
   });
 
   // ========== Delete Session ==========
 
-  app.delete('/api/sessions/:id', async (req): Promise<ApiResponse> => {
+  app.delete('/api/sessions/:id', async (req) => {
     const { id } = req.params as { id: string };
     const query = req.query as { killMux?: string };
     const killMux = query.killMux !== 'false'; // Default to true
@@ -396,7 +395,7 @@ export function registerSessionRoutes(
     }
 
     await ctx.cleanupSession(id, killMux, 'user_delete');
-    return { success: true };
+    return {};
   });
 
   // ========== Delete All Sessions ==========
@@ -473,13 +472,13 @@ export function registerSessionRoutes(
       // Create a fresh tracker if one doesn't exist (shouldn't happen normally)
       const newTracker = new RunSummaryTracker(id, session.name);
       ctx.runSummaryTrackers.set(id, newTracker);
-      return { success: true, summary: newTracker.getSummary() };
+      return { summary: newTracker.getSummary() };
     }
 
     // Update session name in case it changed
     tracker.setSessionName(session.name);
 
-    return { success: true, summary: tracker.getSummary() };
+    return { summary: tracker.getSummary() };
   });
 
   // ========== Get Active Tools ==========
@@ -502,7 +501,7 @@ export function registerSessionRoutes(
 
   // ========== Run Prompt ==========
 
-  app.post('/api/sessions/:id/run', async (req): Promise<ApiResponse> => {
+  app.post('/api/sessions/:id/run', async (req) => {
     const { id } = req.params as { id: string };
     const { prompt } = parseBody(RunPromptSchema, req.body);
     const session = findSessionOrFail(ctx, id);
@@ -517,12 +516,12 @@ export function registerSessionRoutes(
     });
 
     ctx.broadcast(SseEvent.SessionRunning, { id, prompt });
-    return { success: true };
+    return {};
   });
 
   // ========== Start Interactive Mode ==========
 
-  app.post('/api/sessions/:id/interactive', async (req): Promise<ApiResponse> => {
+  app.post('/api/sessions/:id/interactive', async (req) => {
     const { id } = req.params as { id: string };
     const session = findSessionOrFail(ctx, id);
 
@@ -554,7 +553,7 @@ export function registerSessionRoutes(
       ctx.broadcast(SseEvent.SessionInteractive, { id });
       ctx.broadcast(SseEvent.SessionUpdated, { session: ctx.getSessionStateWithRespawn(session) });
 
-      return { success: true };
+      return {};
     } catch (err) {
       return createErrorResponse(ApiErrorCode.OPERATION_FAILED, getErrorMessage(err));
     }
@@ -562,7 +561,7 @@ export function registerSessionRoutes(
 
   // ========== Start Shell Mode ==========
 
-  app.post('/api/sessions/:id/shell', async (req): Promise<ApiResponse> => {
+  app.post('/api/sessions/:id/shell', async (req) => {
     const { id } = req.params as { id: string };
     const session = findSessionOrFail(ctx, id);
 
@@ -580,7 +579,7 @@ export function registerSessionRoutes(
       });
       ctx.broadcast(SseEvent.SessionInteractive, { id, mode: 'shell' });
       ctx.broadcast(SseEvent.SessionUpdated, { session: ctx.getSessionStateWithRespawn(session) });
-      return { success: true };
+      return {};
     } catch (err) {
       return createErrorResponse(ApiErrorCode.OPERATION_FAILED, getErrorMessage(err));
     }
@@ -592,7 +591,7 @@ export function registerSessionRoutes(
 
   // ========== Send Input ==========
 
-  app.post('/api/sessions/:id/input', async (req): Promise<ApiResponse> => {
+  app.post('/api/sessions/:id/input', async (req) => {
     const { id } = req.params as { id: string };
     const { input, useMux } = parseBody(SessionInputWithLimitSchema, req.body);
     const session = findSessionOrFail(ctx, id);
@@ -624,7 +623,7 @@ export function registerSessionRoutes(
     } else {
       session.write(inputStr);
     }
-    return { success: true };
+    return {};
   });
 
   // ========== Send Named Key (tmux send-keys -H) ==========
@@ -632,7 +631,7 @@ export function registerSessionRoutes(
   // Uses send-keys -H (hex) to inject 0x0a (line feed) which Claude Code's
   // Ink input recognizes as "insert newline" vs 0x0d (carriage return = submit).
 
-  app.post('/api/sessions/:id/send-key', async (req): Promise<ApiResponse> => {
+  app.post('/api/sessions/:id/send-key', async (req) => {
     const { id } = req.params as { id: string };
     const body = req.body as Record<string, unknown>;
     const key = typeof body?.key === 'string' ? body.key : '';
@@ -671,18 +670,18 @@ export function registerSessionRoutes(
       console.error('[Server] send-key failed:', err);
       return createErrorResponse(ApiErrorCode.INTERNAL_ERROR, 'tmux send-keys failed');
     }
-    return { success: true };
+    return {};
   });
 
   // ========== Resize Terminal ==========
 
-  app.post('/api/sessions/:id/resize', async (req): Promise<ApiResponse> => {
+  app.post('/api/sessions/:id/resize', async (req) => {
     const { id } = req.params as { id: string };
     const { cols, rows } = parseBody(ResizeSchema, req.body);
     const session = findSessionOrFail(ctx, id);
 
     session.resize(cols, rows);
-    return { success: true };
+    return {};
   });
 
   // ========== Get Last Response (from transcript JSONL) ==========
@@ -1084,7 +1083,7 @@ export function registerSessionRoutes(
       const result = await session.runPrompt(prompt);
       // Clean up session after completion to prevent memory leak
       await ctx.cleanupSession(session.id, true, 'run_prompt_complete');
-      return { success: true, sessionId: session.id, ...result };
+      return { sessionId: session.id, ...result };
     } catch (err) {
       // Clean up session on error too
       await ctx.cleanupSession(session.id, true, 'run_prompt_error');
@@ -1094,7 +1093,7 @@ export function registerSessionRoutes(
 
   // ========== Quick Start ==========
 
-  app.post('/api/quick-start', async (req): Promise<QuickStartResponse> => {
+  app.post('/api/quick-start', async (req) => {
     // Prevent unbounded session creation
     if (ctx.sessions.size >= MAX_CONCURRENT_SESSIONS) {
       return createErrorResponse(
@@ -1263,7 +1262,6 @@ export function registerSessionRoutes(
       }
 
       return {
-        success: true,
         sessionId: session.id,
         casePath,
         caseName,
@@ -1725,6 +1723,6 @@ export function registerSessionRoutes(
       await fh.close();
     }
 
-    return { success: true, path: filepath, filename };
+    return { path: filepath, filename };
   });
 }
diff --git a/src/web/routes/system-routes.ts b/src/web/routes/system-routes.ts
index a472f599..6d593305 100644
--- a/src/web/routes/system-routes.ts
+++ b/src/web/routes/system-routes.ts
@@ -238,7 +238,7 @@ export function registerSystemRoutes(
 
   app.post('/api/tunnel/qr/regenerate', async () => {
     ctx.tunnelManager.regenerateQrToken();
-    return { success: true };
+    return {};
   });
 
   // ========== Auth Session Revocation ==========
@@ -251,7 +251,7 @@ export function registerSystemRoutes(
       // Revoke all sessions (nuclear option)
       ctx.authSessions?.clear();
     }
-    return { success: true };
+    return {};
   });
 
   // ═══════════════════════════════════════════════════════════════
@@ -288,7 +288,7 @@ export function registerSystemRoutes(
       const child = spawn('bash', [scriptPath, url], { detached: true, stdio: 'ignore' });
       child.on('error', (err) => app.log.error({ err }, 'span-displays launch failed'));
       child.unref();
-      return { success: true, url };
+      return { url };
     } catch (err) {
       return reply.code(500).send(createErrorResponse(ApiErrorCode.INTERNAL_ERROR, getErrorMessage(err)));
     }
@@ -313,7 +313,7 @@ export function registerSystemRoutes(
   app.post('/api/system/update', async (_req, reply) => {
     const result = await startUpdate();
     if (result.ok) {
-      return { success: true, updateId: result.updateId, toTag: result.toTag, toVersion: result.toVersion };
+      return { updateId: result.updateId, toTag: result.toTag, toVersion: result.toVersion };
     }
     const map = {
       'in-flight': { http: 409, api: ApiErrorCode.ALREADY_EXISTS },
@@ -354,7 +354,7 @@ export function registerSystemRoutes(
     for (const s of result.cleaned) {
       lifecycleLog.log({ event: 'stale_cleaned', sessionId: s.id, name: s.name });
     }
-    return { success: true, cleanedSessions: result.count };
+    return { cleanedSessions: result.count };
   });
 
   app.get('/api/session-lifecycle', async (req) => {
@@ -371,7 +371,7 @@ export function registerSystemRoutes(
       since: query.since ? Number(query.since) : undefined,
       limit: query.limit ? Math.min(Number(query.limit), 1000) : 200,
     });
-    return { success: true, entries };
+    return { entries };
   });
 
   // ========== Stats ==========
@@ -391,7 +391,6 @@ export function registerSystemRoutes(
   app.get('/api/stats', async () => {
     const activeSessionTokens = collectActiveTokens();
     return {
-      success: true,
       stats: ctx.store.getAggregateStats(activeSessionTokens),
       raw: ctx.store.getGlobalStats(),
     };
@@ -400,7 +399,6 @@ export function registerSystemRoutes(
   app.get('/api/token-stats', async () => {
     const activeSessionTokens = collectActiveTokens();
     return {
-      success: true,
       daily: ctx.store.getDailyStats(30),
       totals: ctx.store.getAggregateStats(activeSessionTokens),
     };
@@ -413,13 +411,13 @@ export function registerSystemRoutes(
   // ========== Config ==========
 
   app.get('/api/config', async () => {
-    return { success: true, config: ctx.store.getConfig() };
+    return { config: ctx.store.getConfig() };
   });
 
   app.put('/api/config', async (req) => {
     const configData = parseBody(ConfigUpdateSchema, req.body, 'Invalid config');
     ctx.store.setConfig(configData as Partial<ReturnType<typeof ctx.store.getConfig>>);
-    return { success: true, config: ctx.store.getConfig() };
+    return { config: ctx.store.getConfig() };
   });
 
   // ========== Debug/Memory ==========
@@ -535,7 +533,7 @@ export function registerSystemRoutes(
         }
       }
 
-      return { success: true };
+      return {};
     } catch (err) {
       return createErrorResponse(ApiErrorCode.OPERATION_FAILED, getErrorMessage(err));
     }
@@ -568,7 +566,7 @@ export function registerSystemRoutes(
       }
       await fs.writeFile(SETTINGS_PATH, JSON.stringify(existingSettings, null, 2));
 
-      return { success: true };
+      return {};
     } catch (err) {
       return createErrorResponse(ApiErrorCode.OPERATION_FAILED, getErrorMessage(err));
     }
@@ -580,7 +578,6 @@ export function registerSystemRoutes(
     const { id } = req.params as { id: string };
     const session = findSessionOrFail(ctx, id);
     return {
-      success: true,
       nice: session.niceConfig,
     };
   });
@@ -596,7 +593,6 @@ export function registerSystemRoutes(
     ctx.broadcast(SseEvent.SessionUpdated, { session: ctx.getSessionStateWithRespawn(session) });
 
     return {
-      success: true,
       nice: session.niceConfig,
       note: 'Nice priority only affects newly created mux sessions, not currently running ones.',
     };
@@ -620,7 +616,7 @@ export function registerSystemRoutes(
         mkdirSync(dir, { recursive: true });
       }
       await fs.writeFile(windowStatesPath, JSON.stringify(states, null, 2));
-      return { success: true };
+      return {};
     } catch (err) {
       return createErrorResponse(ApiErrorCode.OPERATION_FAILED, getErrorMessage(err));
     }
@@ -640,7 +636,7 @@ export function registerSystemRoutes(
         mkdirSync(dir, { recursive: true });
       }
       await fs.writeFile(parentMapPath, JSON.stringify(parentMap, null, 2));
-      return { success: true };
+      return {};
     } catch (err) {
       return createErrorResponse(ApiErrorCode.OPERATION_FAILED, getErrorMessage(err));
     }
@@ -799,7 +795,7 @@ export function registerSystemRoutes(
     const filepath = join(SCREENSHOTS_DIR, filename);
     await fs.writeFile(filepath, filePart.data);
 
-    return { success: true, path: filepath, filename };
+    return { path: filepath, filename };
   });
 
   app.get('/api/screenshots', async () => {
diff --git a/src/web/server.ts b/src/web/server.ts
index b9f7f75f..a0a1c1c0 100644
--- a/src/web/server.ts
+++ b/src/web/server.ts
@@ -90,8 +90,21 @@ import { reconcileUpdateOnBoot } from './self-update.js';
 // Load version from package.json
 const require = createRequire(import.meta.url);
 const { version: APP_VERSION } = require('../../package.json');
+
+/**
+ * `/api/v1/*` is the versioned public alias of the (unversioned) `/api/*` routes.
+ * Rewriting at the server level lets external clients pin to a stable surface while
+ * the bundled frontend keeps using `/api/*`. See docs/api-reference.md.
+ */
+function rewriteApiV1Url(url: string): string {
+  if (url === '/api/v1') return '/api';
+  if (url.startsWith('/api/v1/')) return '/api/' + url.slice('/api/v1/'.length);
+  return url;
+}
 import {
   getErrorMessage,
+  httpStatusForErrorCode,
+  ApiErrorCode,
   type PersistedRespawnConfig,
   type NiceConfig,
   type ImageDetectedEvent,
@@ -274,11 +287,12 @@ export class WebServer extends EventEmitter {
     this.windowTitle = `codeman:${this.titleHostname}`;
     this.indexHtmlTemplate = readFileSync(join(__dirname, 'public', 'index.html'), 'utf-8');
 
+    const rewriteUrl = (req: { url?: string }): string => rewriteApiV1Url(req.url || '');
     if (https) {
       const { key, cert } = getOrCreateSelfSignedCert();
-      this.app = Fastify({ logger: false, https: { key, cert } });
+      this.app = Fastify({ logger: false, https: { key, cert }, rewriteUrl });
     } else {
-      this.app = Fastify({ logger: false });
+      this.app = Fastify({ logger: false, rewriteUrl });
     }
     this.mux = createMultiplexer();
     this.sse = new SseStreamManager(
@@ -561,6 +575,27 @@ export class WebServer extends EventEmitter {
     // Cookie plugin (needed for auth session tokens)
     await this.app.register(fastifyCookie);
 
+    // Uniform response envelope (stable HTTP contract — docs/api-reference.md):
+    // wrap bare JSON payloads as { success:true, data } and map { success:false }
+    // error envelopes to a conventional HTTP status (instead of 200). Skips
+    // non-JSON responses (buffers/streams) and non-/api routes.
+    this.app.addHook('preSerialization', (req, reply, payload: unknown, done) => {
+      if (!req.url.startsWith('/api')) return done(null, payload);
+      if (payload === null || typeof payload !== 'object') return done(null, payload);
+      if (Buffer.isBuffer(payload) || typeof (payload as { pipe?: unknown }).pipe === 'function') {
+        return done(null, payload);
+      }
+      const p = payload as { success?: unknown; errorCode?: unknown };
+      if (p.success === false) {
+        if (reply.statusCode === 200 && typeof p.errorCode === 'string') {
+          reply.code(httpStatusForErrorCode(p.errorCode as ApiErrorCode));
+        }
+        return done(null, payload);
+      }
+      if (p.success === true) return done(null, payload);
+      return done(null, { success: true, data: payload });
+    });
+
     // Anti-DNS-rebinding Host allowlist + cross-site (CSRF) Origin guard. Registered
     // before auth so forged cross-site / rebound requests are rejected up front, even
     // on the default no-password install. See docs/reports/security-review-2026-06-09.md.
diff --git a/test/edge-cases.test.ts b/test/edge-cases.test.ts
index 56201851..d3c1a4bd 100644
--- a/test/edge-cases.test.ts
+++ b/test/edge-cases.test.ts
@@ -190,7 +190,7 @@ describe('Edge Cases and Error Handling', () => {
 
       // Should succeed with valid characters, even if long
       if (data.success) {
-        createdCases.push(longName);
+        createdCases.push(data.data.caseName);
       }
       // Either succeeds or fails gracefully
       expect(data).toHaveProperty('success');
@@ -202,8 +202,8 @@ describe('Edge Cases and Error Handling', () => {
       const response = await fetch(`${baseUrl}/api/sessions/non-existent/respawn`);
       const data = await response.json();
 
-      expect(data.enabled).toBe(false);
-      expect(data.status).toBeNull();
+      expect(data.data.enabled).toBe(false);
+      expect(data.data.status).toBeNull();
     });
 
     it('should handle starting respawn on non-existent session', async () => {
@@ -287,17 +287,17 @@ describe('Concurrent Session Handling', () => {
     // All should succeed
     for (const result of results) {
       expect(result.success).toBe(true);
-      expect(result.session.id).toBeDefined();
+      expect(result.data.session.id).toBeDefined();
     }
 
     // Verify sessions are listed
     const listRes = await fetch(`${baseUrl}/api/sessions`);
     const sessions = await listRes.json();
-    expect(sessions.length).toBeGreaterThanOrEqual(5);
+    expect(sessions.data.length).toBeGreaterThanOrEqual(5);
 
     // Clean up - delete all created sessions
     for (const result of results) {
-      await fetch(`${baseUrl}/api/sessions/${result.session.id}`, {
+      await fetch(`${baseUrl}/api/sessions/${result.data.session.id}`, {
         method: 'DELETE',
       });
     }
@@ -317,7 +317,7 @@ describe('Concurrent Session Handling', () => {
       expect(createData.success).toBe(true);
 
       // Delete immediately
-      const deleteRes = await fetch(`${baseUrl}/api/sessions/${createData.session.id}`, {
+      const deleteRes = await fetch(`${baseUrl}/api/sessions/${createData.data.session.id}`, {
         method: 'DELETE',
       });
       const deleteData = await deleteRes.json();
@@ -341,8 +341,8 @@ describe('Concurrent Session Handling', () => {
 
     for (const result of results) {
       expect(result.success).toBe(true);
-      if (result.caseName) {
-        createdCases.push(result.caseName);
+      if (result.data.caseName) {
+        createdCases.push(result.data.caseName);
       }
     }
 
diff --git a/test/file-link-click.test.ts b/test/file-link-click.test.ts
index d1587ff5..0cdd745a 100644
--- a/test/file-link-click.test.ts
+++ b/test/file-link-click.test.ts
@@ -147,7 +147,7 @@ describe('File Link Click Tests', () => {
 
     const data = await response.json();
     expect(data.success).toBe(true);
-    createdSessions.push(data.session.id);
+    createdSessions.push(data.data.sessionId);
 
     // Wait for session to appear in UI
     await new Promise((r) => setTimeout(r, 2000));
@@ -347,7 +347,7 @@ describe('File Link Click Tests', () => {
       });
       const data = await response.json();
       expect(data.success).toBe(true);
-      sessionId = data.sessionId; // quick-start returns sessionId directly
+      sessionId = data.data.sessionId; // quick-start returns sessionId under data envelope
       createdSessions.push(sessionId);
     }
 
diff --git a/test/hooks-config.test.ts b/test/hooks-config.test.ts
index 697f7a27..513d14ad 100644
--- a/test/hooks-config.test.ts
+++ b/test/hooks-config.test.ts
@@ -32,21 +32,21 @@ describe('generateHooksConfig', () => {
   it('should configure idle_prompt matcher', () => {
     const config = generateHooksConfig();
     const notifHooks = config.hooks.Notification as Array<{ matcher?: string }>;
-    const idleHook = notifHooks.find(h => h.matcher === 'idle_prompt');
+    const idleHook = notifHooks.find((h) => h.matcher === 'idle_prompt');
     expect(idleHook).toBeDefined();
   });
 
   it('should configure permission_prompt matcher', () => {
     const config = generateHooksConfig();
     const notifHooks = config.hooks.Notification as Array<{ matcher?: string }>;
-    const permHook = notifHooks.find(h => h.matcher === 'permission_prompt');
+    const permHook = notifHooks.find((h) => h.matcher === 'permission_prompt');
     expect(permHook).toBeDefined();
   });
 
   it('should configure elicitation_dialog matcher', () => {
     const config = generateHooksConfig();
     const notifHooks = config.hooks.Notification as Array<{ matcher?: string }>;
-    const elicitHook = notifHooks.find(h => h.matcher === 'elicitation_dialog');
+    const elicitHook = notifHooks.find((h) => h.matcher === 'elicitation_dialog');
     expect(elicitHook).toBeDefined();
   });
 
@@ -146,7 +146,7 @@ describe('writeHooksConfig', () => {
     mkdirSync(claudeDir, { recursive: true });
     writeFileSync(
       join(claudeDir, 'settings.local.json'),
-      JSON.stringify({ existingKey: 'existingValue', permissions: { allow: ['Read'] } }, null, 2),
+      JSON.stringify({ existingKey: 'existingValue', permissions: { allow: ['Read'] } }, null, 2)
     );
 
     await writeHooksConfig(testDir);
@@ -160,10 +160,7 @@ describe('writeHooksConfig', () => {
   it('should overwrite existing hooks key', async () => {
     const claudeDir = join(testDir, '.claude');
     mkdirSync(claudeDir, { recursive: true });
-    writeFileSync(
-      join(claudeDir, 'settings.local.json'),
-      JSON.stringify({ hooks: { oldHook: [] } }, null, 2),
-    );
+    writeFileSync(join(claudeDir, 'settings.local.json'), JSON.stringify({ hooks: { oldHook: [] } }, null, 2));
 
     await writeHooksConfig(testDir);
 
@@ -214,7 +211,7 @@ describe('Hook Event API', () => {
       body: JSON.stringify({}),
     });
     const createData = await createRes.json();
-    testSessionId = createData.session.id;
+    testSessionId = createData.data.session.id;
   });
 
   afterAll(async () => {
@@ -396,7 +393,7 @@ describe('Hook Data Sanitization', () => {
       body: JSON.stringify({}),
     });
     const createData = await createRes.json();
-    testSessionId = createData.session.id;
+    testSessionId = createData.data.session.id;
   });
 
   afterAll(async () => {
@@ -641,7 +638,7 @@ describe('Hook Config Generation - Extended', () => {
   it('should include all event types', () => {
     const config = generateHooksConfig();
     const notifHooks = config.hooks.Notification as Array<{ matcher?: string }>;
-    const matchers = notifHooks.map(n => n.matcher);
+    const matchers = notifHooks.map((n) => n.matcher);
     expect(matchers).toContain('idle_prompt');
     expect(matchers).toContain('permission_prompt');
     expect(matchers).toContain('elicitation_dialog');
@@ -694,7 +691,10 @@ describe('Hook Config Generation - Extended', () => {
 
   it('should have consistent structure across all notification hooks', () => {
     const config = generateHooksConfig();
-    const notifHooks = config.hooks.Notification as Array<{ matcher: string; hooks: Array<{ type: string; command: string; timeout: number }> }>;
+    const notifHooks = config.hooks.Notification as Array<{
+      matcher: string;
+      hooks: Array<{ type: string; command: string; timeout: number }>;
+    }>;
 
     for (const hook of notifHooks) {
       expect(hook.matcher).toBeDefined();
diff --git a/test/integration-flows.test.ts b/test/integration-flows.test.ts
index 48abde03..727c7ebb 100644
--- a/test/integration-flows.test.ts
+++ b/test/integration-flows.test.ts
@@ -58,24 +58,24 @@ describe('Integration Flows', () => {
       const quickStartData = await quickStartRes.json();
 
       expect(quickStartData.success).toBe(true);
-      expect(quickStartData.sessionId).toBeDefined();
-      expect(quickStartData.caseName).toBe(caseName);
-      createdSessions.push(quickStartData.sessionId);
+      expect(quickStartData.data.sessionId).toBeDefined();
+      expect(quickStartData.data.caseName).toBe(caseName);
+      createdSessions.push(quickStartData.data.sessionId);
 
       // Step 2: Verify session is in interactive mode
-      const sessionRes = await fetch(`${baseUrl}/api/sessions/${quickStartData.sessionId}`);
+      const sessionRes = await fetch(`${baseUrl}/api/sessions/${quickStartData.data.sessionId}`);
       const sessionData = await sessionRes.json();
 
-      expect(sessionData.id).toBe(quickStartData.sessionId);
-      expect(sessionData.workingDir).toContain(caseName);
-      expect(['busy', 'idle', 'running']).toContain(sessionData.status); // May transition quickly in test mode
+      expect(sessionData.data.id).toBe(quickStartData.data.sessionId);
+      expect(sessionData.data.workingDir).toContain(caseName);
+      expect(['busy', 'idle', 'running']).toContain(sessionData.data.status); // May transition quickly in test mode
 
       // Step 3: Verify case was created with CLAUDE.md
       const caseRes = await fetch(`${baseUrl}/api/cases/${caseName}`);
       const caseData = await caseRes.json();
 
-      expect(caseData.name).toBe(caseName);
-      expect(caseData.hasClaudeMd).toBe(true);
+      expect(caseData.data.name).toBe(caseName);
+      expect(caseData.data.hasClaudeMd).toBe(true);
     });
 
     it('should reuse existing case when quick starting with existing case name', async () => {
@@ -90,10 +90,10 @@ describe('Integration Flows', () => {
       });
       const firstData = await firstRes.json();
       expect(firstData.success).toBe(true);
-      createdSessions.push(firstData.sessionId);
+      createdSessions.push(firstData.data.sessionId);
 
       // Delete the session but keep the case
-      await fetch(`${baseUrl}/api/sessions/${firstData.sessionId}`, { method: 'DELETE' });
+      await fetch(`${baseUrl}/api/sessions/${firstData.data.sessionId}`, { method: 'DELETE' });
 
       // Second quick start - should reuse the case
       const secondRes = await fetch(`${baseUrl}/api/quick-start`, {
@@ -104,9 +104,9 @@ describe('Integration Flows', () => {
       const secondData = await secondRes.json();
 
       expect(secondData.success).toBe(true);
-      expect(secondData.caseName).toBe(caseName);
-      expect(secondData.casePath).toBe(firstData.casePath);
-      createdSessions.push(secondData.sessionId);
+      expect(secondData.data.caseName).toBe(caseName);
+      expect(secondData.data.casePath).toBe(firstData.data.casePath);
+      createdSessions.push(secondData.data.sessionId);
     });
   });
 
@@ -132,20 +132,20 @@ describe('Integration Flows', () => {
       });
       const sessionData = await sessionRes.json();
       expect(sessionData.success).toBe(true);
-      createdSessions.push(sessionData.session.id);
+      createdSessions.push(sessionData.data.session.id);
 
       // Step 3: Start interactive mode
-      const interactiveRes = await fetch(`${baseUrl}/api/sessions/${sessionData.session.id}/interactive`, {
+      const interactiveRes = await fetch(`${baseUrl}/api/sessions/${sessionData.data.session.id}/interactive`, {
         method: 'POST',
       });
       const interactiveData = await interactiveRes.json();
       expect(interactiveData.success).toBe(true);
 
       // Verify session state
-      const verifyRes = await fetch(`${baseUrl}/api/sessions/${sessionData.session.id}`);
+      const verifyRes = await fetch(`${baseUrl}/api/sessions/${sessionData.data.session.id}`);
       const verifyData = await verifyRes.json();
-      expect(['busy', 'idle', 'running']).toContain(verifyData.status);
-      expect(verifyData.workingDir).toContain(caseName);
+      expect(['busy', 'idle', 'running']).toContain(verifyData.data.status);
+      expect(verifyData.data.workingDir).toContain(caseName);
     });
   });
 
@@ -162,13 +162,13 @@ describe('Integration Flows', () => {
       });
       const quickStartData = await quickStartRes.json();
       expect(quickStartData.success).toBe(true);
-      createdSessions.push(quickStartData.sessionId);
+      createdSessions.push(quickStartData.data.sessionId);
 
       // Wait for Claude to start up
       await new Promise((resolve) => setTimeout(resolve, 2000));
 
       // Send input
-      const inputRes = await fetch(`${baseUrl}/api/sessions/${quickStartData.sessionId}/input`, {
+      const inputRes = await fetch(`${baseUrl}/api/sessions/${quickStartData.data.sessionId}/input`, {
         method: 'POST',
         headers: { 'Content-Type': 'application/json' },
         body: JSON.stringify({ input: '/help\n' }),
@@ -180,9 +180,9 @@ describe('Integration Flows', () => {
       await new Promise((resolve) => setTimeout(resolve, 1000));
 
       // Check terminal buffer has content
-      const terminalRes = await fetch(`${baseUrl}/api/sessions/${quickStartData.sessionId}/terminal`);
+      const terminalRes = await fetch(`${baseUrl}/api/sessions/${quickStartData.data.sessionId}/terminal`);
       const terminalData = await terminalRes.json();
-      expect(terminalData.terminalBuffer.length).toBeGreaterThan(0);
+      expect(terminalData.data.terminalBuffer.length).toBeGreaterThan(0);
     });
 
     it('should handle terminal resize', async () => {
@@ -197,15 +197,21 @@ describe('Integration Flows', () => {
       });
       const quickStartData = await quickStartRes.json();
       expect(quickStartData.success).toBe(true);
-      createdSessions.push(quickStartData.sessionId);
+      createdSessions.push(quickStartData.data.sessionId);
 
-      // Resize terminal
-      const resizeRes = await fetch(`${baseUrl}/api/sessions/${quickStartData.sessionId}/resize`, {
-        method: 'POST',
-        headers: { 'Content-Type': 'application/json' },
-        body: JSON.stringify({ cols: 200, rows: 50 }),
-      });
-      const resizeData = await resizeRes.json();
+      // Resize terminal (retry briefly — a just-quick-started session can be
+      // momentarily busy, which would return SESSION_BUSY; this is a transient race).
+      let resizeData;
+      for (let attempt = 0; attempt < 5; attempt++) {
+        const resizeRes = await fetch(`${baseUrl}/api/sessions/${quickStartData.data.sessionId}/resize`, {
+          method: 'POST',
+          headers: { 'Content-Type': 'application/json' },
+          body: JSON.stringify({ cols: 200, rows: 50 }),
+        });
+        resizeData = await resizeRes.json();
+        if (resizeData.success) break;
+        await new Promise((r) => setTimeout(r, 100));
+      }
       expect(resizeData.success).toBe(true);
     });
   });
@@ -225,14 +231,14 @@ describe('Integration Flows', () => {
       expect(quickStartData.success).toBe(true);
 
       // Delete the session
-      const deleteRes = await fetch(`${baseUrl}/api/sessions/${quickStartData.sessionId}`, {
+      const deleteRes = await fetch(`${baseUrl}/api/sessions/${quickStartData.data.sessionId}`, {
         method: 'DELETE',
       });
       const deleteData = await deleteRes.json();
       expect(deleteData.success).toBe(true);
 
       // Verify session is gone
-      const verifyRes = await fetch(`${baseUrl}/api/sessions/${quickStartData.sessionId}`);
+      const verifyRes = await fetch(`${baseUrl}/api/sessions/${quickStartData.data.sessionId}`);
       const verifyData = await verifyRes.json();
       expect(verifyData.error).toContain('not found');
     });
@@ -251,20 +257,20 @@ describe('Integration Flows', () => {
       });
       const quickStartData = await quickStartRes.json();
       expect(quickStartData.success).toBe(true);
-      createdSessions.push(quickStartData.sessionId);
+      createdSessions.push(quickStartData.data.sessionId);
 
       // Get full status
       const statusRes = await fetch(`${baseUrl}/api/status`);
       const statusData = await statusRes.json();
 
-      expect(statusData.sessions).toBeDefined();
-      expect(Array.isArray(statusData.sessions)).toBe(true);
-      expect(statusData.scheduledRuns).toBeDefined();
-      expect(statusData.respawnStatus).toBeDefined();
-      expect(statusData.timestamp).toBeDefined();
+      expect(statusData.data.sessions).toBeDefined();
+      expect(Array.isArray(statusData.data.sessions)).toBe(true);
+      expect(statusData.data.scheduledRuns).toBeDefined();
+      expect(statusData.data.respawnStatus).toBeDefined();
+      expect(statusData.data.timestamp).toBeDefined();
 
       // Verify our session is in the list
-      const ourSession = statusData.sessions.find((s: any) => s.id === quickStartData.sessionId);
+      const ourSession = statusData.data.sessions.find((s: any) => s.id === quickStartData.data.sessionId);
       expect(ourSession).toBeDefined();
       expect(ourSession.workingDir).toContain(caseName);
     });
@@ -341,7 +347,7 @@ describe('SSE Event Flow', () => {
     });
     const quickStartData = await quickStartRes.json();
     expect(quickStartData.success).toBe(true);
-    createdSessions.push(quickStartData.sessionId);
+    createdSessions.push(quickStartData.data.sessionId);
 
     // Wait for events
     await new Promise((resolve) => setTimeout(resolve, 500));
diff --git a/test/operation-lightspeed.test.ts b/test/operation-lightspeed.test.ts
index c1c3a351..34056cb4 100644
--- a/test/operation-lightspeed.test.ts
+++ b/test/operation-lightspeed.test.ts
@@ -88,10 +88,10 @@ async function createSession(baseUrl: string): Promise<string> {
     body: JSON.stringify({ workingDir: '/tmp' }),
   });
   const data = await res.json();
-  if (!data.session?.id) {
+  if (!data.data?.session?.id) {
     throw new Error(`Failed to create session: ${JSON.stringify(data)}`);
   }
-  return data.session.id;
+  return data.data.session.id;
 }
 
 // Helper to delete a session
@@ -392,9 +392,9 @@ describe('Operation Lightspeed', () => {
 
       expect(res.status).toBe(200);
       // terminalBuffer may be empty for a fresh session, but field should exist
-      expect(data).toHaveProperty('terminalBuffer');
-      expect(data).toHaveProperty('truncated');
-      expect(data.truncated).toBe(false);
+      expect(data.data).toHaveProperty('terminalBuffer');
+      expect(data.data).toHaveProperty('truncated');
+      expect(data.data.truncated).toBe(false);
 
       await deleteSession(baseUrl, sessionId);
     });
@@ -407,7 +407,7 @@ describe('Operation Lightspeed', () => {
       const data = await res.json();
 
       expect(res.status).toBe(200);
-      expect(data).toHaveProperty('terminalBuffer');
+      expect(data.data).toHaveProperty('terminalBuffer');
 
       await deleteSession(baseUrl, sessionId);
     });
@@ -431,7 +431,7 @@ describe('Operation Lightspeed', () => {
 
       // All should succeed
       for (const data of results) {
-        expect(data).toHaveProperty('terminalBuffer');
+        expect(data.data).toHaveProperty('terminalBuffer');
       }
 
       // Cleanup
@@ -692,7 +692,8 @@ describe('Operation Lightspeed', () => {
       const sessionId = await createSession(baseUrl);
 
       const res = await fetch(`${baseUrl}/api/sessions`);
-      const sessions = await res.json();
+      const body = await res.json();
+      const sessions = body.data;
 
       expect(Array.isArray(sessions)).toBe(true);
       const session = sessions.find((s: any) => s.id === sessionId);
@@ -718,7 +719,8 @@ describe('Operation Lightspeed', () => {
       await new Promise((resolve) => setTimeout(resolve, 1100));
 
       const res = await fetch(`${baseUrl}/api/sessions`);
-      const sessions = await res.json();
+      const body = await res.json();
+      const sessions = body.data;
 
       // All 3 should be present in the response
       const foundIds = sessions.map((s: any) => s.id);
@@ -911,10 +913,10 @@ describe('Operation Lightspeed', () => {
 
       expect(res.status).toBe(200);
       // Local echo overlay needs session status to know when to show/hide
-      expect(data).toHaveProperty('status');
-      expect(typeof data.status).toBe('string');
+      expect(data.data).toHaveProperty('status');
+      expect(typeof data.data.status).toBe('string');
       // Fresh session starts as 'starting'
-      expect(['starting', 'running', 'idle', 'error']).toContain(data.status);
+      expect(['starting', 'running', 'idle', 'error']).toContain(data.data.status);
 
       await deleteSession(baseUrl, sessionId);
     });
@@ -926,9 +928,9 @@ describe('Operation Lightspeed', () => {
       const data = await res.json();
 
       expect(res.status).toBe(200);
-      expect(data).toHaveProperty('fullSize');
-      expect(typeof data.fullSize).toBe('number');
-      expect(data.fullSize).toBeGreaterThanOrEqual(0);
+      expect(data.data).toHaveProperty('fullSize');
+      expect(typeof data.data.fullSize).toBe('number');
+      expect(data.data.fullSize).toBeGreaterThanOrEqual(0);
 
       await deleteSession(baseUrl, sessionId);
     });
@@ -942,9 +944,9 @@ describe('Operation Lightspeed', () => {
       ]);
 
       // tail=0 means "don't tail" — should return same as no tail param
-      expect(fullRes.truncated).toBe(false);
-      expect(tailZeroRes.truncated).toBe(false);
-      expect(fullRes.terminalBuffer).toBe(tailZeroRes.terminalBuffer);
+      expect(fullRes.data.truncated).toBe(false);
+      expect(tailZeroRes.data.truncated).toBe(false);
+      expect(fullRes.data.terminalBuffer).toBe(tailZeroRes.data.terminalBuffer);
 
       await deleteSession(baseUrl, sessionId);
     });
@@ -957,8 +959,8 @@ describe('Operation Lightspeed', () => {
       const data = await res.json();
 
       expect(res.status).toBe(200);
-      expect(data).toHaveProperty('terminalBuffer');
-      expect(data.truncated).toBe(false); // Can't truncate if tail > fullSize
+      expect(data.data).toHaveProperty('terminalBuffer');
+      expect(data.data.truncated).toBe(false); // Can't truncate if tail > fullSize
 
       await deleteSession(baseUrl, sessionId);
     });
@@ -971,7 +973,7 @@ describe('Operation Lightspeed', () => {
 
       // Should handle gracefully (either return full buffer or error cleanly)
       expect(res.status).toBe(200);
-      expect(data).toHaveProperty('terminalBuffer');
+      expect(data.data).toHaveProperty('terminalBuffer');
 
       await deleteSession(baseUrl, sessionId);
     });
@@ -984,7 +986,7 @@ describe('Operation Lightspeed', () => {
 
       // NaN tail should be handled (parseInt('abc') = NaN, which is falsy)
       expect(res.status).toBe(200);
-      expect(data).toHaveProperty('terminalBuffer');
+      expect(data.data).toHaveProperty('terminalBuffer');
 
       await deleteSession(baseUrl, sessionId);
     });
@@ -1235,7 +1237,7 @@ describe('Operation Lightspeed', () => {
         )
       );
 
-      const ids = results.map((r) => r.session.id);
+      const ids = results.map((r) => r.data.session.id);
       expect(ids.length).toBe(5);
       expect(new Set(ids).size).toBe(5); // All unique
 
diff --git a/test/qr-auth.test.ts b/test/qr-auth.test.ts
index 077cac45..1d96fa08 100644
--- a/test/qr-auth.test.ts
+++ b/test/qr-auth.test.ts
@@ -86,8 +86,7 @@ describe('QR Token Manager (unit)', () => {
 
     // Manually expire the token by manipulating its createdAt
     // Access the private map — this is a unit test, we need to verify the TTL logic
-    const tokenMap = (tm as unknown as { qrTokensByCode: Map<string, { createdAt: number }> })
-      .qrTokensByCode;
+    const tokenMap = (tm as unknown as { qrTokensByCode: Map<string, { createdAt: number }> }).qrTokensByCode;
     const record = tokenMap.get(code)!;
     record.createdAt = Date.now() - 91_000; // 91 seconds ago (beyond 90s grace)
 
@@ -99,8 +98,7 @@ describe('QR Token Manager (unit)', () => {
     const code = tm.getCurrentShortCode()!;
 
     // Set createdAt to 80 seconds ago (within 90s grace)
-    const tokenMap = (tm as unknown as { qrTokensByCode: Map<string, { createdAt: number }> })
-      .qrTokensByCode;
+    const tokenMap = (tm as unknown as { qrTokensByCode: Map<string, { createdAt: number }> }).qrTokensByCode;
     const record = tokenMap.get(code)!;
     record.createdAt = Date.now() - 80_000;
 
@@ -172,8 +170,7 @@ describe('QR Token Manager (unit)', () => {
 
   it('should accept token at exactly grace period (90000ms)', () => {
     const code = tm.getCurrentShortCode()!;
-    const tokenMap = (tm as unknown as { qrTokensByCode: Map<string, { createdAt: number }> })
-      .qrTokensByCode;
+    const tokenMap = (tm as unknown as { qrTokensByCode: Map<string, { createdAt: number }> }).qrTokensByCode;
     const record = tokenMap.get(code)!;
     record.createdAt = Date.now() - 90_000;
     // Condition is `> QR_TOKEN_GRACE_MS` (strict >), so exactly 90000 should pass
@@ -182,8 +179,7 @@ describe('QR Token Manager (unit)', () => {
 
   it('should reject token at grace period + 1ms (90001ms)', () => {
     const code = tm.getCurrentShortCode()!;
-    const tokenMap = (tm as unknown as { qrTokensByCode: Map<string, { createdAt: number }> })
-      .qrTokensByCode;
+    const tokenMap = (tm as unknown as { qrTokensByCode: Map<string, { createdAt: number }> }).qrTokensByCode;
     const record = tokenMap.get(code)!;
     record.createdAt = Date.now() - 90_001;
     expect(tm.consumeToken(code)).toBe(false);
@@ -308,8 +304,7 @@ describe('QR Auth Integration', () => {
   beforeEach(() => {
     // Reset QR failure counter to prevent cross-test contamination
     // (all requests come from 127.0.0.1)
-    const qrFailures = (server as unknown as { qrAuthFailures: { clear(): void } | null })
-      .qrAuthFailures;
+    const qrFailures = (server as unknown as { qrAuthFailures: { clear(): void } | null }).qrAuthFailures;
     if (qrFailures) qrFailures.clear();
   });
 
@@ -568,9 +563,11 @@ describe('QR Auth Integration', () => {
       const setCookie = res.headers.get('set-cookie')!;
       const token = setCookie.match(/codeman_session=([^;]+)/)![1];
 
-      const authSessions = (server as unknown as {
-        authSessions: { get(k: string): { method: string } | undefined } | null;
-      }).authSessions;
+      const authSessions = (
+        server as unknown as {
+          authSessions: { get(k: string): { method: string } | undefined } | null;
+        }
+      ).authSessions;
       const record = authSessions?.get(token);
       expect(record).toBeDefined();
       expect(record!.method).toBe('qr');
@@ -631,9 +628,9 @@ describe('QR SVG Endpoint (GET /api/tunnel/qr)', () => {
       });
       expect(res.status).toBe(200);
       const data = await res.json();
-      expect(data.authEnabled).toBe(true);
-      expect(data.svg).toContain('<svg');
-      expect(data.svg).toContain('</svg>');
+      expect(data.data.authEnabled).toBe(true);
+      expect(data.data.svg).toContain('<svg');
+      expect(data.data.svg).toContain('</svg>');
     } finally {
       tm.stopTokenRotation();
       simulateTunnelStopped(tm);
@@ -653,9 +650,9 @@ describe('QR SVG Endpoint (GET /api/tunnel/qr)', () => {
       });
       expect(res.status).toBe(200);
       const data = await res.json();
-      expect(data.authEnabled).toBe(false);
-      expect(data.svg).toContain('<svg');
-      expect(data.svg).toContain('</svg>');
+      expect(data.data.authEnabled).toBe(false);
+      expect(data.data.svg).toContain('<svg');
+      expect(data.data.svg).toContain('</svg>');
     } finally {
       process.env.CODEMAN_PASSWORD = savedPass;
       simulateTunnelStopped(tm);
@@ -709,8 +706,8 @@ describe('QR SVG Endpoint (GET /api/tunnel/qr)', () => {
       });
       expect(res.status).toBe(200);
       const data = await res.json();
-      expect(data.svg).toContain('<svg');
-      expect(data.authEnabled).toBe(false);
+      expect(data.data.svg).toContain('<svg');
+      expect(data.data.authEnabled).toBe(false);
     } finally {
       process.env.CODEMAN_PASSWORD = savedPass;
       simulateTunnelStopped(tm);
@@ -732,7 +729,7 @@ describe('QR SVG Endpoint (GET /api/tunnel/qr)', () => {
       });
       const data2 = await res2.json();
 
-      expect(data1.svg).toBe(data2.svg);
+      expect(data1.data.svg).toBe(data2.data.svg);
     } finally {
       tm.stopTokenRotation();
       simulateTunnelStopped(tm);
@@ -756,7 +753,7 @@ describe('QR SVG Endpoint (GET /api/tunnel/qr)', () => {
       });
       const data2 = await res2.json();
 
-      expect(data1.svg).not.toBe(data2.svg);
+      expect(data1.data.svg).not.toBe(data2.data.svg);
     } finally {
       tm.stopTokenRotation();
       simulateTunnelStopped(tm);
diff --git a/test/quick-start.test.ts b/test/quick-start.test.ts
index 6b16dc74..330fe5d9 100644
--- a/test/quick-start.test.ts
+++ b/test/quick-start.test.ts
@@ -47,14 +47,14 @@ describe('Quick Start API', () => {
       const data = await response.json();
 
       expect(data.success).toBe(true);
-      expect(data.sessionId).toBeDefined();
-      expect(data.caseName).toBe(testCaseName);
-      expect(data.casePath).toBe(join(CASES_DIR, testCaseName));
+      expect(data.data.sessionId).toBeDefined();
+      expect(data.data.caseName).toBe(testCaseName);
+      expect(data.data.casePath).toBe(join(CASES_DIR, testCaseName));
 
       // Verify case folder was created
-      expect(existsSync(data.casePath)).toBe(true);
-      expect(existsSync(join(data.casePath, 'CLAUDE.md'))).toBe(true);
-      expect(existsSync(join(data.casePath, 'src'))).toBe(true);
+      expect(existsSync(data.data.casePath)).toBe(true);
+      expect(existsSync(join(data.data.casePath, 'CLAUDE.md'))).toBe(true);
+      expect(existsSync(join(data.data.casePath, 'src'))).toBe(true);
     });
 
     it('should use existing case without recreating it', async () => {
@@ -74,7 +74,7 @@ describe('Quick Start API', () => {
       const data = await response.json();
 
       expect(data.success).toBe(true);
-      expect(data.caseName).toBe(testCaseName);
+      expect(data.data.caseName).toBe(testCaseName);
       // Case should exist but CLAUDE.md won't be created since case already exists
       expect(existsSync(casePath)).toBe(true);
     });
@@ -118,7 +118,7 @@ describe('Quick Start API', () => {
       const data = await response.json();
 
       expect(data.success).toBe(true);
-      expect(data.caseName).toBe(testCaseName);
+      expect(data.data.caseName).toBe(testCaseName);
     });
 
     it('should default to "testcase" when no caseName provided', async () => {
@@ -137,7 +137,7 @@ describe('Quick Start API', () => {
       const data = await response.json();
 
       expect(data.success).toBe(true);
-      expect(data.caseName).toBe('testcase');
+      expect(data.data.caseName).toBe('testcase');
     });
   });
 });
@@ -167,10 +167,10 @@ describe('Session Management', () => {
       const data = await response.json();
 
       expect(data.success).toBe(true);
-      expect(data.session).toBeDefined();
-      expect(data.session.id).toBeDefined();
-      expect(data.session.workingDir).toBe('/tmp');
-      expect(data.session.status).toBe('idle');
+      expect(data.data.session).toBeDefined();
+      expect(data.data.session.id).toBeDefined();
+      expect(data.data.session.workingDir).toBe('/tmp');
+      expect(data.data.session.status).toBe('idle');
     });
   });
 
@@ -179,7 +179,8 @@ describe('Session Management', () => {
       const response = await fetch(`${baseUrl}/api/sessions`);
       const data = await response.json();
 
-      expect(Array.isArray(data)).toBe(true);
+      expect(data.success).toBe(true);
+      expect(Array.isArray(data.data)).toBe(true);
     });
   });
 
@@ -188,12 +189,13 @@ describe('Session Management', () => {
       const response = await fetch(`${baseUrl}/api/status`);
       const data = await response.json();
 
-      expect(data).toHaveProperty('sessions');
-      expect(data).toHaveProperty('scheduledRuns');
-      expect(data).toHaveProperty('respawnStatus');
-      expect(data).toHaveProperty('timestamp');
-      expect(Array.isArray(data.sessions)).toBe(true);
-      expect(Array.isArray(data.scheduledRuns)).toBe(true);
+      expect(data.success).toBe(true);
+      expect(data.data).toHaveProperty('sessions');
+      expect(data.data).toHaveProperty('scheduledRuns');
+      expect(data.data).toHaveProperty('respawnStatus');
+      expect(data.data).toHaveProperty('timestamp');
+      expect(Array.isArray(data.data.sessions)).toBe(true);
+      expect(Array.isArray(data.data.scheduledRuns)).toBe(true);
     });
   });
 });
@@ -224,7 +226,8 @@ describe('Case Management', () => {
       const response = await fetch(`${baseUrl}/api/cases`);
       const data = await response.json();
 
-      expect(Array.isArray(data)).toBe(true);
+      expect(data.success).toBe(true);
+      expect(Array.isArray(data.data)).toBe(true);
     });
   });
 
@@ -298,9 +301,10 @@ describe('Case Management', () => {
       const response = await fetch(`${baseUrl}/api/cases/${testCaseName}`);
       const data = await response.json();
 
-      expect(data.name).toBe(testCaseName);
-      expect(data.path).toBeDefined();
-      expect(data.hasClaudeMd).toBe(true);
+      expect(data.success).toBe(true);
+      expect(data.data.name).toBe(testCaseName);
+      expect(data.data.path).toBeDefined();
+      expect(data.data.hasClaudeMd).toBe(true);
     });
 
     it('should return error for non-existent case', async () => {
diff --git a/test/ralph-integration.test.ts b/test/ralph-integration.test.ts
index 27521066..46316339 100644
--- a/test/ralph-integration.test.ts
+++ b/test/ralph-integration.test.ts
@@ -61,7 +61,7 @@ describe('Ralph Integration Tests', () => {
       const data = await res.json();
 
       expect(res.status).toBe(200);
-      expect(Array.isArray(data)).toBe(true);
+      expect(Array.isArray(data.data)).toBe(true);
     });
 
     it('should create a new session via quick-start', async () => {
@@ -76,8 +76,8 @@ describe('Ralph Integration Tests', () => {
       const data = await res.json();
 
       expect(data.success).toBe(true);
-      expect(data.sessionId).toBeDefined();
-      createdSessions.push(data.sessionId);
+      expect(data.data.sessionId).toBeDefined();
+      createdSessions.push(data.data.sessionId);
     });
 
     it('should get session details by ID', async () => {
@@ -91,15 +91,15 @@ describe('Ralph Integration Tests', () => {
         body: JSON.stringify({ caseName }),
       });
       const createData = await createRes.json();
-      createdSessions.push(createData.sessionId);
+      createdSessions.push(createData.data.sessionId);
 
       // Get session details
-      const res = await fetch(`${baseUrl}/api/sessions/${createData.sessionId}`);
+      const res = await fetch(`${baseUrl}/api/sessions/${createData.data.sessionId}`);
       const data = await res.json();
 
       expect(res.status).toBe(200);
-      expect(data.id).toBe(createData.sessionId);
-      expect(data.workingDir).toContain(caseName);
+      expect(data.data.id).toBe(createData.data.sessionId);
+      expect(data.data.workingDir).toContain(caseName);
     });
 
     it('should return error for non-existent session', async () => {
@@ -122,7 +122,7 @@ describe('Ralph Integration Tests', () => {
         body: JSON.stringify({ caseName }),
       });
       const createData = await createRes.json();
-      const sessionId = createData.sessionId;
+      const sessionId = createData.data.sessionId;
 
       // Delete session
       const deleteRes = await fetch(`${baseUrl}/api/sessions/${sessionId}`, {
@@ -152,13 +152,13 @@ describe('Ralph Integration Tests', () => {
       const data = await res.json();
 
       expect(data.success).toBe(true);
-      expect(data.sessionId).toBeDefined();
-      createdSessions.push(data.sessionId);
+      expect(data.data.sessionId).toBeDefined();
+      createdSessions.push(data.data.sessionId);
 
       // Verify mode
-      const sessionRes = await fetch(`${baseUrl}/api/sessions/${data.sessionId}`);
+      const sessionRes = await fetch(`${baseUrl}/api/sessions/${data.data.sessionId}`);
       const sessionData = await sessionRes.json();
-      expect(sessionData.mode).toBe('shell');
+      expect(sessionData.data.mode).toBe('shell');
     });
   });
 
@@ -175,9 +175,9 @@ describe('Ralph Integration Tests', () => {
         body: JSON.stringify({ caseName }),
       });
       const createData = await createRes.json();
-      createdSessions.push(createData.sessionId);
+      createdSessions.push(createData.data.sessionId);
 
-      const res = await fetch(`${baseUrl}/api/sessions/${createData.sessionId}/ralph-state`);
+      const res = await fetch(`${baseUrl}/api/sessions/${createData.data.sessionId}/ralph-state`);
       const data = await res.json();
 
       expect(res.status).toBe(200);
@@ -206,7 +206,7 @@ describe('Ralph Integration Tests', () => {
       const data = await res.json();
 
       expect(res.status).toBe(200);
-      expect(Array.isArray(data)).toBe(true);
+      expect(Array.isArray(data.data)).toBe(true);
     });
 
     it('should create a new case', async () => {
@@ -244,7 +244,7 @@ describe('Ralph Integration Tests', () => {
       });
       const data = await res.json();
 
-      expect(res.status).toBe(200);
+      expect(res.status).toBe(409);
       expect(data.success).toBe(false);
       expect(data.error).toContain('already exists');
     });
@@ -265,15 +265,15 @@ describe('Ralph Integration Tests', () => {
       const data = await res.json();
 
       expect(res.status).toBe(200);
-      expect(data.name).toBe(caseName);
-      expect(data.path).toContain(caseName);
+      expect(data.data.name).toBe(caseName);
+      expect(data.data.path).toContain(caseName);
     });
 
     it('should return error for non-existent case', async () => {
       const res = await fetch(`${baseUrl}/api/cases/non-existent-case-12345`);
       const data = await res.json();
 
-      expect(res.status).toBe(200);
+      expect(res.status).toBe(404);
       expect(data.error).toBe('Case not found');
     });
   });
@@ -286,18 +286,18 @@ describe('Ralph Integration Tests', () => {
       const data = await res.json();
 
       expect(res.status).toBe(200);
-      expect(data.sessions).toBeDefined();
-      expect(data.scheduledRuns).toBeDefined();
-      expect(data.respawnStatus).toBeDefined();
-      expect(data.timestamp).toBeDefined();
+      expect(data.data.sessions).toBeDefined();
+      expect(data.data.scheduledRuns).toBeDefined();
+      expect(data.data.respawnStatus).toBeDefined();
+      expect(data.data.timestamp).toBeDefined();
     });
 
     it('should include sessions array in status', async () => {
       const res = await fetch(`${baseUrl}/api/status`);
       const data = await res.json();
 
-      expect(Array.isArray(data.sessions)).toBe(true);
-      expect(typeof data.timestamp).toBe('number');
+      expect(Array.isArray(data.data.sessions)).toBe(true);
+      expect(typeof data.data.timestamp).toBe('number');
     });
   });
 
@@ -309,9 +309,9 @@ describe('Ralph Integration Tests', () => {
       const data = await res.json();
 
       expect(res.status).toBe(200);
-      expect(data.sessions).toBeDefined();
-      expect(Array.isArray(data.sessions)).toBe(true);
-      expect(typeof data.muxAvailable).toBe('boolean');
+      expect(data.data.sessions).toBeDefined();
+      expect(Array.isArray(data.data.sessions)).toBe(true);
+      expect(typeof data.data.muxAvailable).toBe('boolean');
     });
   });
 
@@ -328,9 +328,9 @@ describe('Ralph Integration Tests', () => {
         body: JSON.stringify({ caseName }),
       });
       const createData = await createRes.json();
-      createdSessions.push(createData.sessionId);
+      createdSessions.push(createData.data.sessionId);
 
-      const res = await fetch(`${baseUrl}/api/sessions/${createData.sessionId}/input`, {
+      const res = await fetch(`${baseUrl}/api/sessions/${createData.data.sessionId}/input`, {
         method: 'POST',
         headers: { 'Content-Type': 'application/json' },
         body: JSON.stringify({ input: 'test input' }),
@@ -351,9 +351,9 @@ describe('Ralph Integration Tests', () => {
         body: JSON.stringify({ caseName }),
       });
       const createData = await createRes.json();
-      createdSessions.push(createData.sessionId);
+      createdSessions.push(createData.data.sessionId);
 
-      const res = await fetch(`${baseUrl}/api/sessions/${createData.sessionId}/input`, {
+      const res = await fetch(`${baseUrl}/api/sessions/${createData.data.sessionId}/input`, {
         method: 'POST',
         headers: { 'Content-Type': 'application/json' },
         body: JSON.stringify({ input: null }),
@@ -393,12 +393,12 @@ describe('Ralph Integration Tests', () => {
       });
       const createData = await createRes.json();
       expect(createData.success).toBe(true);
-      createdSessions.push(createData.sessionId);
+      createdSessions.push(createData.data.sessionId);
 
       // Wait for session to be ready
       await new Promise((r) => setTimeout(r, 200));
 
-      const res = await fetch(`${baseUrl}/api/sessions/${createData.sessionId}/resize`, {
+      const res = await fetch(`${baseUrl}/api/sessions/${createData.data.sessionId}/resize`, {
         method: 'POST',
         headers: { 'Content-Type': 'application/json' },
         body: JSON.stringify({ cols: 120, rows: 40 }),
@@ -420,12 +420,12 @@ describe('Ralph Integration Tests', () => {
       });
       const createData = await createRes.json();
       expect(createData.success).toBe(true);
-      createdSessions.push(createData.sessionId);
+      createdSessions.push(createData.data.sessionId);
 
       // Wait for session to be ready
       await new Promise((r) => setTimeout(r, 200));
 
-      const res = await fetch(`${baseUrl}/api/sessions/${createData.sessionId}/resize`, {
+      const res = await fetch(`${baseUrl}/api/sessions/${createData.data.sessionId}/resize`, {
         method: 'POST',
         headers: { 'Content-Type': 'application/json' },
         body: JSON.stringify({ cols: -1, rows: 40 }),
@@ -452,9 +452,9 @@ describe('Ralph Integration Tests', () => {
       });
       const createData = await createRes.json();
       expect(createData.success).toBe(true);
-      createdSessions.push(createData.sessionId);
+      createdSessions.push(createData.data.sessionId);
 
-      const res = await fetch(`${baseUrl}/api/sessions/${createData.sessionId}/auto-compact`, {
+      const res = await fetch(`${baseUrl}/api/sessions/${createData.data.sessionId}/auto-compact`, {
         method: 'POST',
         headers: { 'Content-Type': 'application/json' },
         body: JSON.stringify({ enabled: true, threshold: 100000 }),
@@ -489,9 +489,9 @@ describe('Ralph Integration Tests', () => {
       });
       const createData = await createRes.json();
       expect(createData.success).toBe(true);
-      createdSessions.push(createData.sessionId);
+      createdSessions.push(createData.data.sessionId);
 
-      const res = await fetch(`${baseUrl}/api/sessions/${createData.sessionId}/auto-compact`, {
+      const res = await fetch(`${baseUrl}/api/sessions/${createData.data.sessionId}/auto-compact`, {
         method: 'POST',
         headers: { 'Content-Type': 'application/json' },
         body: JSON.stringify({ enabled: true, threshold: -100 }),
@@ -516,9 +516,9 @@ describe('Ralph Integration Tests', () => {
       });
       const createData = await createRes.json();
       expect(createData.success).toBe(true);
-      createdSessions.push(createData.sessionId);
+      createdSessions.push(createData.data.sessionId);
 
-      const res = await fetch(`${baseUrl}/api/sessions/${createData.sessionId}/auto-clear`, {
+      const res = await fetch(`${baseUrl}/api/sessions/${createData.data.sessionId}/auto-clear`, {
         method: 'POST',
         headers: { 'Content-Type': 'application/json' },
         body: JSON.stringify({ enabled: true, threshold: 150000 }),
@@ -553,9 +553,9 @@ describe('Ralph Integration Tests', () => {
       });
       const createData = await createRes.json();
       expect(createData.success).toBe(true);
-      createdSessions.push(createData.sessionId);
+      createdSessions.push(createData.data.sessionId);
 
-      const res = await fetch(`${baseUrl}/api/sessions/${createData.sessionId}/auto-clear`, {
+      const res = await fetch(`${baseUrl}/api/sessions/${createData.data.sessionId}/auto-clear`, {
         method: 'POST',
         headers: { 'Content-Type': 'application/json' },
         body: JSON.stringify({ enabled: true, threshold: -50 }),
@@ -582,9 +582,9 @@ describe('Ralph Integration Tests', () => {
       });
       const createData = await createRes.json();
       expect(createData.success).toBe(true);
-      createdSessions.push(createData.sessionId);
+      createdSessions.push(createData.data.sessionId);
 
-      const res = await fetch(`${baseUrl}/api/sessions/${createData.sessionId}/ralph-config`, {
+      const res = await fetch(`${baseUrl}/api/sessions/${createData.data.sessionId}/ralph-config`, {
         method: 'POST',
         headers: { 'Content-Type': 'application/json' },
         body: JSON.stringify({ enabled: true }),
@@ -606,9 +606,9 @@ describe('Ralph Integration Tests', () => {
       });
       const createData = await createRes.json();
       expect(createData.success).toBe(true);
-      createdSessions.push(createData.sessionId);
+      createdSessions.push(createData.data.sessionId);
 
-      const res = await fetch(`${baseUrl}/api/sessions/${createData.sessionId}/ralph-config`, {
+      const res = await fetch(`${baseUrl}/api/sessions/${createData.data.sessionId}/ralph-config`, {
         method: 'POST',
         headers: { 'Content-Type': 'application/json' },
         body: JSON.stringify({ reset: true }),
@@ -643,9 +643,9 @@ describe('Ralph Integration Tests', () => {
       });
       const createData = await createRes.json();
       expect(createData.success).toBe(true);
-      createdSessions.push(createData.sessionId);
+      createdSessions.push(createData.data.sessionId);
 
-      const res = await fetch(`${baseUrl}/api/sessions/${createData.sessionId}/ralph-config`, {
+      const res = await fetch(`${baseUrl}/api/sessions/${createData.data.sessionId}/ralph-config`, {
         method: 'POST',
         headers: { 'Content-Type': 'application/json' },
         body: JSON.stringify({ reset: 'full' }),
@@ -667,9 +667,9 @@ describe('Ralph Integration Tests', () => {
       });
       const createData = await createRes.json();
       expect(createData.success).toBe(true);
-      createdSessions.push(createData.sessionId);
+      createdSessions.push(createData.data.sessionId);
 
-      const res = await fetch(`${baseUrl}/api/sessions/${createData.sessionId}/ralph-config`, {
+      const res = await fetch(`${baseUrl}/api/sessions/${createData.data.sessionId}/ralph-config`, {
         method: 'POST',
         headers: { 'Content-Type': 'application/json' },
         body: JSON.stringify({ enabled: true, completionPhrase: 'DONE' }),
@@ -680,7 +680,7 @@ describe('Ralph Integration Tests', () => {
       expect(data.success).toBe(true);
 
       // Verify the state was updated
-      const stateRes = await fetch(`${baseUrl}/api/sessions/${createData.sessionId}/ralph-state`);
+      const stateRes = await fetch(`${baseUrl}/api/sessions/${createData.data.sessionId}/ralph-state`);
       const stateData = await stateRes.json();
 
       expect(stateData.success).toBe(true);
@@ -698,9 +698,9 @@ describe('Ralph Integration Tests', () => {
       });
       const createData = await createRes.json();
       expect(createData.success).toBe(true);
-      createdSessions.push(createData.sessionId);
+      createdSessions.push(createData.data.sessionId);
 
-      const res = await fetch(`${baseUrl}/api/sessions/${createData.sessionId}/ralph-config`, {
+      const res = await fetch(`${baseUrl}/api/sessions/${createData.data.sessionId}/ralph-config`, {
         method: 'POST',
         headers: { 'Content-Type': 'application/json' },
         body: JSON.stringify({ disableAutoEnable: true }),
@@ -726,9 +726,9 @@ describe('Ralph Integration Tests', () => {
       });
       const createData = await createRes.json();
       expect(createData.success).toBe(true);
-      createdSessions.push(createData.sessionId);
+      createdSessions.push(createData.data.sessionId);
 
-      const res = await fetch(`${baseUrl}/api/sessions/${createData.sessionId}/ralph-state`);
+      const res = await fetch(`${baseUrl}/api/sessions/${createData.data.sessionId}/ralph-state`);
       const data = await res.json();
 
       expect(res.status).toBe(200);
@@ -750,17 +750,17 @@ describe('Ralph Integration Tests', () => {
       });
       const createData = await createRes.json();
       expect(createData.success).toBe(true);
-      createdSessions.push(createData.sessionId);
+      createdSessions.push(createData.data.sessionId);
 
       // Enable ralph tracking
-      await fetch(`${baseUrl}/api/sessions/${createData.sessionId}/ralph-config`, {
+      await fetch(`${baseUrl}/api/sessions/${createData.data.sessionId}/ralph-config`, {
         method: 'POST',
         headers: { 'Content-Type': 'application/json' },
         body: JSON.stringify({ enabled: true, completionPhrase: 'TASK_DONE' }),
       });
 
       // Check state
-      const res = await fetch(`${baseUrl}/api/sessions/${createData.sessionId}/ralph-state`);
+      const res = await fetch(`${baseUrl}/api/sessions/${createData.data.sessionId}/ralph-state`);
       const data = await res.json();
 
       expect(data.success).toBe(true);
@@ -779,17 +779,17 @@ describe('Ralph Integration Tests', () => {
       });
       const createData = await createRes.json();
       expect(createData.success).toBe(true);
-      createdSessions.push(createData.sessionId);
+      createdSessions.push(createData.data.sessionId);
 
       // Enable first
-      await fetch(`${baseUrl}/api/sessions/${createData.sessionId}/ralph-config`, {
+      await fetch(`${baseUrl}/api/sessions/${createData.data.sessionId}/ralph-config`, {
         method: 'POST',
         headers: { 'Content-Type': 'application/json' },
         body: JSON.stringify({ enabled: true }),
       });
 
       // Then reset
-      const resetRes = await fetch(`${baseUrl}/api/sessions/${createData.sessionId}/ralph-config`, {
+      const resetRes = await fetch(`${baseUrl}/api/sessions/${createData.data.sessionId}/ralph-config`, {
         method: 'POST',
         headers: { 'Content-Type': 'application/json' },
         body: JSON.stringify({ reset: true }),
@@ -799,7 +799,7 @@ describe('Ralph Integration Tests', () => {
       expect(resetData.success).toBe(true);
 
       // Check that todos are cleared
-      const stateRes = await fetch(`${baseUrl}/api/sessions/${createData.sessionId}/ralph-state`);
+      const stateRes = await fetch(`${baseUrl}/api/sessions/${createData.data.sessionId}/ralph-state`);
       const stateData = await stateRes.json();
 
       expect(stateData.success).toBe(true);
@@ -817,24 +817,24 @@ describe('Ralph Integration Tests', () => {
       });
       const createData = await createRes.json();
       expect(createData.success).toBe(true);
-      createdSessions.push(createData.sessionId);
+      createdSessions.push(createData.data.sessionId);
 
       // Enable tracking
-      await fetch(`${baseUrl}/api/sessions/${createData.sessionId}/ralph-config`, {
+      await fetch(`${baseUrl}/api/sessions/${createData.data.sessionId}/ralph-config`, {
         method: 'POST',
         headers: { 'Content-Type': 'application/json' },
         body: JSON.stringify({ enabled: true }),
       });
 
       // Soft reset (keep enabled)
-      await fetch(`${baseUrl}/api/sessions/${createData.sessionId}/ralph-config`, {
+      await fetch(`${baseUrl}/api/sessions/${createData.data.sessionId}/ralph-config`, {
         method: 'POST',
         headers: { 'Content-Type': 'application/json' },
         body: JSON.stringify({ reset: true }),
       });
 
       // Check state
-      const stateRes = await fetch(`${baseUrl}/api/sessions/${createData.sessionId}/ralph-state`);
+      const stateRes = await fetch(`${baseUrl}/api/sessions/${createData.data.sessionId}/ralph-state`);
       const stateData = await stateRes.json();
 
       expect(stateData.success).toBe(true);
@@ -852,24 +852,24 @@ describe('Ralph Integration Tests', () => {
       });
       const createData = await createRes.json();
       expect(createData.success).toBe(true);
-      createdSessions.push(createData.sessionId);
+      createdSessions.push(createData.data.sessionId);
 
       // Enable tracking
-      await fetch(`${baseUrl}/api/sessions/${createData.sessionId}/ralph-config`, {
+      await fetch(`${baseUrl}/api/sessions/${createData.data.sessionId}/ralph-config`, {
         method: 'POST',
         headers: { 'Content-Type': 'application/json' },
         body: JSON.stringify({ enabled: true }),
       });
 
       // Full reset
-      await fetch(`${baseUrl}/api/sessions/${createData.sessionId}/ralph-config`, {
+      await fetch(`${baseUrl}/api/sessions/${createData.data.sessionId}/ralph-config`, {
         method: 'POST',
         headers: { 'Content-Type': 'application/json' },
         body: JSON.stringify({ reset: 'full' }),
       });
 
       // Check state
-      const stateRes = await fetch(`${baseUrl}/api/sessions/${createData.sessionId}/ralph-state`);
+      const stateRes = await fetch(`${baseUrl}/api/sessions/${createData.data.sessionId}/ralph-state`);
       const stateData = await stateRes.json();
 
       expect(stateData.success).toBe(true);
@@ -891,13 +891,13 @@ describe('Ralph Integration Tests', () => {
       });
       const createData = await createRes.json();
       expect(createData.success).toBe(true);
-      createdSessions.push(createData.sessionId);
+      createdSessions.push(createData.data.sessionId);
 
-      const res = await fetch(`${baseUrl}/api/sessions/${createData.sessionId}/respawn`);
+      const res = await fetch(`${baseUrl}/api/sessions/${createData.data.sessionId}/respawn`);
       const data = await res.json();
 
       expect(res.status).toBe(200);
-      expect(data.enabled).toBe(false);
+      expect(data.data.enabled).toBe(false);
     });
 
     it('should return error for respawn start on non-existent session', async () => {
@@ -924,14 +924,14 @@ describe('Ralph Integration Tests', () => {
       });
       const createData = await createRes.json();
       expect(createData.success).toBe(true);
-      createdSessions.push(createData.sessionId);
+      createdSessions.push(createData.data.sessionId);
 
-      const res = await fetch(`${baseUrl}/api/sessions/${createData.sessionId}/respawn/stop`, {
+      const res = await fetch(`${baseUrl}/api/sessions/${createData.data.sessionId}/respawn/stop`, {
         method: 'POST',
       });
       const data = await res.json();
 
-      expect(res.status).toBe(200);
+      expect(res.status).toBe(404);
       expect(data.success).toBe(false);
       expect(data.errorCode).toBe('NOT_FOUND');
     });
@@ -947,9 +947,9 @@ describe('Ralph Integration Tests', () => {
       });
       const createData = await createRes.json();
       expect(createData.success).toBe(true);
-      createdSessions.push(createData.sessionId);
+      createdSessions.push(createData.data.sessionId);
 
-      const res = await fetch(`${baseUrl}/api/sessions/${createData.sessionId}/respawn/config`, {
+      const res = await fetch(`${baseUrl}/api/sessions/${createData.data.sessionId}/respawn/config`, {
         method: 'PUT',
         headers: { 'Content-Type': 'application/json' },
         body: JSON.stringify({ idleTimeoutMs: 10000 }),
@@ -958,7 +958,7 @@ describe('Ralph Integration Tests', () => {
 
       expect(res.status).toBe(200);
       expect(data.success).toBe(true);
-      expect(data.config.idleTimeoutMs).toBe(10000);
+      expect(data.data.config.idleTimeoutMs).toBe(10000);
     });
   });
 
@@ -976,9 +976,9 @@ describe('Ralph Integration Tests', () => {
       });
       const createData = await createRes.json();
       expect(createData.success).toBe(true);
-      createdSessions.push(createData.sessionId);
+      createdSessions.push(createData.data.sessionId);
 
-      const res = await fetch(`${baseUrl}/api/sessions/${createData.sessionId}/output`);
+      const res = await fetch(`${baseUrl}/api/sessions/${createData.data.sessionId}/output`);
       const data = await res.json();
 
       expect(res.status).toBe(200);
@@ -1008,14 +1008,14 @@ describe('Ralph Integration Tests', () => {
       });
       const createData = await createRes.json();
       expect(createData.success).toBe(true);
-      createdSessions.push(createData.sessionId);
+      createdSessions.push(createData.data.sessionId);
 
-      const res = await fetch(`${baseUrl}/api/sessions/${createData.sessionId}/terminal`);
+      const res = await fetch(`${baseUrl}/api/sessions/${createData.data.sessionId}/terminal`);
       const data = await res.json();
 
       expect(res.status).toBe(200);
-      expect(data.terminalBuffer).toBeDefined();
-      expect(data.status).toBeDefined();
+      expect(data.data.terminalBuffer).toBeDefined();
+      expect(data.data.status).toBeDefined();
     });
 
     it('should return error for terminal of non-existent session', async () => {
diff --git a/test/routes/case-routes.test.ts b/test/routes/case-routes.test.ts
index 4b620b50..ac1a60f5 100644
--- a/test/routes/case-routes.test.ts
+++ b/test/routes/case-routes.test.ts
@@ -3,10 +3,22 @@
  *
  * Uses app.inject() — no real HTTP ports needed.
  * Port: N/A (app.inject doesn't open ports)
+ *
+ * Responses follow the uniform envelope contract:
+ *   SUCCESS -> HTTP 2xx, body = { success: true, data: <payload> }
+ *   ERROR   -> HTTP 4xx/5xx, body = { success: false, error, errorCode }
+ * Bare handler returns are wrapped into { success:true, data } and returned
+ * error envelopes are mapped to their conventional HTTP status by the same
+ * preSerialization hook the production server installs (mirrored below so test
+ * behavior matches production exactly).
  */
 
 import { describe, it, expect, beforeEach, afterEach, vi } from 'vitest';
-import { createRouteTestHarness, type RouteTestHarness } from './_route-test-utils.js';
+import Fastify, { type FastifyInstance } from 'fastify';
+import fastifyCookie from '@fastify/cookie';
+import { createMockRouteContext, type MockRouteContext } from '../mocks/index.js';
+import { installRouteErrorHandler } from '../../src/web/route-error-handler.js';
+import { ApiErrorCode, httpStatusForErrorCode } from '../../src/types.js';
 import { registerCaseRoutes } from '../../src/web/routes/case-routes.js';
 
 // Mock filesystem modules
@@ -51,11 +63,52 @@ const mockedReaddirSync = vi.mocked(readdirSync);
 const mockedReaddir = vi.mocked(fs.readdir);
 const mockedReadFile = vi.mocked(fs.readFile);
 
+interface CaseRouteHarness {
+  app: FastifyInstance;
+  ctx: MockRouteContext;
+}
+
+/**
+ * Build a route harness that mirrors production: cookie plugin, the shared
+ * route error handler, AND the uniform-envelope preSerialization hook (copied
+ * from src/web/server.ts) so bare handler returns become { success:true, data }
+ * and returned error envelopes get mapped to a conventional HTTP status.
+ */
+async function createEnvelopeHarness(): Promise<CaseRouteHarness> {
+  const app = Fastify({ logger: false });
+  await app.register(fastifyCookie);
+
+  // Uniform response envelope (matches src/web/server.ts preSerialization hook).
+  app.addHook('preSerialization', (req, reply, payload: unknown, done) => {
+    if (!req.url.startsWith('/api')) return done(null, payload);
+    if (payload === null || typeof payload !== 'object') return done(null, payload);
+    if (Buffer.isBuffer(payload) || typeof (payload as { pipe?: unknown }).pipe === 'function') {
+      return done(null, payload);
+    }
+    const p = payload as { success?: unknown; errorCode?: unknown };
+    if (p.success === false) {
+      if (reply.statusCode === 200 && typeof p.errorCode === 'string') {
+        reply.code(httpStatusForErrorCode(p.errorCode as ApiErrorCode));
+      }
+      return done(null, payload);
+    }
+    if (p.success === true) return done(null, payload);
+    return done(null, { success: true, data: payload });
+  });
+
+  const ctx = createMockRouteContext();
+  registerCaseRoutes(app, ctx as never);
+  installRouteErrorHandler(app);
+  await app.ready();
+
+  return { app, ctx };
+}
+
 describe('case-routes', () => {
-  let harness: RouteTestHarness;
+  let harness: CaseRouteHarness;
 
   beforeEach(async () => {
-    harness = await createRouteTestHarness(registerCaseRoutes);
+    harness = await createEnvelopeHarness();
     vi.clearAllMocks();
 
     // Default: existsSync returns false, readFile throws ENOENT
@@ -79,7 +132,8 @@ describe('case-routes', () => {
       });
       expect(res.statusCode).toBe(200);
       const body = JSON.parse(res.body);
-      expect(body).toEqual([]);
+      expect(body.success).toBe(true);
+      expect(body.data).toEqual([]);
     });
 
     it('returns cases from CASES_DIR', async () => {
@@ -97,10 +151,10 @@ describe('case-routes', () => {
       });
       expect(res.statusCode).toBe(200);
       const body = JSON.parse(res.body);
-      expect(body).toHaveLength(2);
-      expect(body[0].name).toBe('my-case');
-      expect(body[1].name).toBe('other-case');
-      expect(body[0].hasClaudeMd).toBe(false);
+      expect(body.data).toHaveLength(2);
+      expect(body.data[0].name).toBe('my-case');
+      expect(body.data[1].name).toBe('other-case');
+      expect(body.data[0].hasClaudeMd).toBe(false);
     });
 
     it('includes hasClaudeMd flag', async () => {
@@ -113,7 +167,7 @@ describe('case-routes', () => {
       });
       expect(res.statusCode).toBe(200);
       const body = JSON.parse(res.body);
-      expect(body[0].hasClaudeMd).toBe(true);
+      expect(body.data[0].hasClaudeMd).toBe(true);
     });
 
     it('includes linked cases from linked-cases.json', async () => {
@@ -141,7 +195,7 @@ describe('case-routes', () => {
       expect(res.statusCode).toBe(200);
       const body = JSON.parse(res.body);
       // Should have both regular and linked cases
-      expect(body.length).toBeGreaterThanOrEqual(1);
+      expect(body.data.length).toBeGreaterThanOrEqual(1);
     });
   });
 
@@ -189,7 +243,7 @@ describe('case-routes', () => {
         url: '/api/cases',
         payload: { name: 'existing-case' },
       });
-      expect(res.statusCode).toBe(200);
+      expect(res.statusCode).toBe(409);
       const body = JSON.parse(res.body);
       expect(body.success).toBe(false);
       expect(body.error).toContain('already exists');
@@ -250,7 +304,7 @@ describe('case-routes', () => {
         url: '/api/cases/link',
         payload: { name: 'my-project', path: '/nonexistent/path' },
       });
-      expect(res.statusCode).toBe(200);
+      expect(res.statusCode).toBe(404);
       const body = JSON.parse(res.body);
       expect(body.success).toBe(false);
       expect(body.error).toContain('not found');
@@ -265,7 +319,7 @@ describe('case-routes', () => {
         url: '/api/cases/link',
         payload: { name: 'existing-case', path: '/home/user/project' },
       });
-      expect(res.statusCode).toBe(200);
+      expect(res.statusCode).toBe(409);
       const body = JSON.parse(res.body);
       expect(body.success).toBe(false);
       expect(body.error).toContain('already exists');
@@ -310,8 +364,9 @@ describe('case-routes', () => {
       });
       expect(res.statusCode).toBe(200);
       const body = JSON.parse(res.body);
-      expect(body.name).toBe('my-case');
-      expect(body.linked).toBe(true);
+      expect(body.success).toBe(true);
+      expect(body.data.name).toBe('my-case');
+      expect(body.data.linked).toBe(true);
     });
 
     it('returns CASES_DIR case when no linked case found', async () => {
@@ -326,7 +381,8 @@ describe('case-routes', () => {
       });
       expect(res.statusCode).toBe(200);
       const body = JSON.parse(res.body);
-      expect(body.name).toBe('regular-case');
+      expect(body.success).toBe(true);
+      expect(body.data.name).toBe('regular-case');
     });
 
     it('returns error when case not found anywhere', async () => {
@@ -337,7 +393,7 @@ describe('case-routes', () => {
         method: 'GET',
         url: '/api/cases/nonexistent',
       });
-      expect(res.statusCode).toBe(200);
+      expect(res.statusCode).toBe(404);
       const body = JSON.parse(res.body);
       expect(body.success).toBe(false);
       expect(body.error).toContain('not found');
@@ -358,9 +414,9 @@ describe('case-routes', () => {
       expect(res.statusCode).toBe(200);
       const body = JSON.parse(res.body);
       expect(body.success).toBe(true);
-      expect(body.exists).toBe(false);
-      expect(body.content).toBeNull();
-      expect(body.todos).toEqual([]);
+      expect(body.data.exists).toBe(false);
+      expect(body.data.content).toBeNull();
+      expect(body.data.todos).toEqual([]);
     });
 
     it('parses fix plan with todos and stats', async () => {
@@ -397,9 +453,9 @@ describe('case-routes', () => {
       expect(res.statusCode).toBe(200);
       const body = JSON.parse(res.body);
       expect(body.success).toBe(true);
-      expect(body.exists).toBe(true);
-      expect(body.todos.length).toBeGreaterThan(0);
-      expect(body.stats.total).toBeGreaterThan(0);
+      expect(body.data.exists).toBe(true);
+      expect(body.data.todos.length).toBeGreaterThan(0);
+      expect(body.data.stats.total).toBeGreaterThan(0);
     });
   });
 
@@ -413,7 +469,7 @@ describe('case-routes', () => {
         method: 'GET',
         url: '/api/cases/my-case/ralph-wizard/files',
       });
-      expect(res.statusCode).toBe(200);
+      expect(res.statusCode).toBe(404);
       const body = JSON.parse(res.body);
       expect(body.success).toBe(false);
       expect(body.error).toContain('not found');
@@ -424,7 +480,7 @@ describe('case-routes', () => {
         method: 'GET',
         url: '/api/cases/..%2F..%2Fetc/ralph-wizard/files',
       });
-      expect(res.statusCode).toBe(200);
+      expect(res.statusCode).toBe(400);
       const body = JSON.parse(res.body);
       expect(body.success).toBe(false);
     });
@@ -464,7 +520,7 @@ describe('case-routes', () => {
         method: 'GET',
         url: '/api/cases/my-case/ralph-wizard/file/research%2Fprompt.md',
       });
-      expect(res.statusCode).toBe(200);
+      expect(res.statusCode).toBe(404);
       const body = JSON.parse(res.body);
       expect(body.success).toBe(false);
     });
diff --git a/test/routes/hook-event-routes.test.ts b/test/routes/hook-event-routes.test.ts
index c8f5587a..279d2c3a 100644
--- a/test/routes/hook-event-routes.test.ts
+++ b/test/routes/hook-event-routes.test.ts
@@ -3,17 +3,73 @@
  *
  * Uses app.inject() — no real HTTP ports needed.
  * Port: N/A (app.inject doesn't open ports)
+ *
+ * These tests assert the UNIFORM response envelope (stable HTTP contract):
+ *   success -> 2xx, { success: true, data: <payload> }
+ *   error   -> 4xx/5xx, { success: false, error, errorCode }
+ * The production server applies this via a preSerialization hook (server.ts).
+ * The shared route harness doesn't install it, so we build a local harness here
+ * that mirrors production: the same preSerialization envelope hook + the shared
+ * route error handler, so assertions match the real wire format.
  */
 
 import { describe, it, expect, beforeEach, afterEach, vi } from 'vitest';
-import { createRouteTestHarness, type RouteTestHarness } from './_route-test-utils.js';
+import Fastify, { type FastifyInstance } from 'fastify';
+import fastifyCookie from '@fastify/cookie';
+import { createMockRouteContext, type MockRouteContext } from '../mocks/index.js';
+import { installRouteErrorHandler } from '../../src/web/route-error-handler.js';
+import { ApiErrorCode, httpStatusForErrorCode } from '../../src/types.js';
 import { registerHookEventRoutes } from '../../src/web/routes/hook-event-routes.js';
 
+interface LocalHarness {
+  app: FastifyInstance;
+  ctx: MockRouteContext;
+}
+
+/**
+ * Build a Fastify instance that mirrors production's uniform-envelope behavior
+ * (server.ts preSerialization hook) so the test wire format matches the contract:
+ * bare payloads become { success: true, data }, and { success:false } error
+ * envelopes get the conventional HTTP status from their errorCode.
+ */
+async function createEnvelopeHarness(
+  registerFn: (app: FastifyInstance, ctx: MockRouteContext) => void
+): Promise<LocalHarness> {
+  const app = Fastify({ logger: false });
+  await app.register(fastifyCookie);
+
+  const ctx = createMockRouteContext();
+  registerFn(app, ctx);
+
+  // Mirror production uniform response envelope (server.ts).
+  app.addHook('preSerialization', (req, reply, payload: unknown, done) => {
+    if (!req.url.startsWith('/api')) return done(null, payload);
+    if (payload === null || typeof payload !== 'object') return done(null, payload);
+    if (Buffer.isBuffer(payload) || typeof (payload as { pipe?: unknown }).pipe === 'function') {
+      return done(null, payload);
+    }
+    const p = payload as { success?: unknown; errorCode?: unknown };
+    if (p.success === false) {
+      if (reply.statusCode === 200 && typeof p.errorCode === 'string') {
+        reply.code(httpStatusForErrorCode(p.errorCode as ApiErrorCode));
+      }
+      return done(null, payload);
+    }
+    if (p.success === true) return done(null, payload);
+    return done(null, { success: true, data: payload });
+  });
+
+  installRouteErrorHandler(app);
+  await app.ready();
+
+  return { app, ctx };
+}
+
 describe('hook-event-routes', () => {
-  let harness: RouteTestHarness;
+  let harness: LocalHarness;
 
   beforeEach(async () => {
-    harness = await createRouteTestHarness(registerHookEventRoutes);
+    harness = await createEnvelopeHarness(registerHookEventRoutes);
   });
 
   afterEach(async () => {
@@ -69,7 +125,7 @@ describe('hook-event-routes', () => {
           data: null,
         },
       });
-      expect(res.statusCode).toBe(200);
+      expect(res.statusCode).toBe(404);
       const body = JSON.parse(res.body);
       expect(body.success).toBe(false);
       expect(body.error).toBeDefined();
diff --git a/test/routes/mux-routes.test.ts b/test/routes/mux-routes.test.ts
index fada50a7..999d6452 100644
--- a/test/routes/mux-routes.test.ts
+++ b/test/routes/mux-routes.test.ts
@@ -15,9 +15,7 @@ describe('mux-routes', () => {
   beforeEach(async () => {
     // Add mux methods that mux-routes needs but mock-route-context doesn't provide
     harness = await createRouteTestHarness(registerMuxRoutes);
-    harness.ctx.mux.getSessionsWithStats = vi.fn(async () => [
-      { name: 'codeman-abc', pid: 1234, created: Date.now() },
-    ]);
+    harness.ctx.mux.getSessionsWithStats = vi.fn(async () => [{ name: 'codeman-abc', pid: 1234, created: Date.now() }]);
     harness.ctx.mux.isAvailable = vi.fn(() => true);
     harness.ctx.mux.reconcileSessions = vi.fn(async () => ({
       orphaned: [],
@@ -74,7 +72,7 @@ describe('mux-routes', () => {
       });
       expect(res.statusCode).toBe(200);
       const body = JSON.parse(res.body);
-      expect(body.success).toBe(true);
+      expect(body.killed).toBe(true);
       expect(harness.ctx.mux.killSession).toHaveBeenCalledWith('codeman-abc');
     });
 
@@ -87,7 +85,7 @@ describe('mux-routes', () => {
       });
       expect(res.statusCode).toBe(200);
       const body = JSON.parse(res.body);
-      expect(body.success).toBe(false);
+      expect(body.killed).toBe(false);
     });
   });
 
@@ -119,7 +117,7 @@ describe('mux-routes', () => {
       });
       expect(res.statusCode).toBe(200);
       const body = JSON.parse(res.body);
-      expect(body.success).toBe(true);
+      expect(body).toEqual({});
       expect(harness.ctx.mux.startStatsCollection).toHaveBeenCalled();
     });
   });
@@ -134,7 +132,7 @@ describe('mux-routes', () => {
       });
       expect(res.statusCode).toBe(200);
       const body = JSON.parse(res.body);
-      expect(body.success).toBe(true);
+      expect(body).toEqual({});
       expect(harness.ctx.mux.stopStatsCollection).toHaveBeenCalled();
     });
   });
diff --git a/test/routes/push-routes.test.ts b/test/routes/push-routes.test.ts
index 20ee2777..4b10e97b 100644
--- a/test/routes/push-routes.test.ts
+++ b/test/routes/push-routes.test.ts
@@ -131,7 +131,11 @@ describe('push-routes', () => {
       });
       expect(res.statusCode).toBe(200);
       const body = JSON.parse(res.body);
-      expect(body.success).toBe(true);
+      // Handler returns a bare {} on success; the uniform envelope wraps it to
+      // { success:true, data:{} } in production. At the route-handler layer the
+      // harness sees the bare return, so the meaningful check is the empty body
+      // plus the pushStore call below.
+      expect(body).toEqual({});
       expect(harness.ctx.pushStore.updatePreferences).toHaveBeenCalledWith('sub-123', {
         'session:idle': true,
         'session:error': true,
@@ -176,7 +180,11 @@ describe('push-routes', () => {
       });
       expect(res.statusCode).toBe(200);
       const body = JSON.parse(res.body);
-      expect(body.success).toBe(true);
+      // Handler returns a bare {} on success; the uniform envelope wraps it to
+      // { success:true, data:{} } in production. At the route-handler layer the
+      // harness sees the bare return, so the meaningful check is the empty body
+      // plus the pushStore call below.
+      expect(body).toEqual({});
       expect(harness.ctx.pushStore.removeSubscription).toHaveBeenCalledWith('sub-123');
     });
 
diff --git a/test/routes/ralph-routes.test.ts b/test/routes/ralph-routes.test.ts
index b44db4de..f0050b47 100644
--- a/test/routes/ralph-routes.test.ts
+++ b/test/routes/ralph-routes.test.ts
@@ -62,7 +62,7 @@ describe('ralph-routes', () => {
       });
       expect(res.statusCode).toBe(200);
       const body = JSON.parse(res.body);
-      expect(body.success).toBe(true);
+      expect(body).toEqual({});
     });
 
     it('enables ralph tracker', async () => {
@@ -230,7 +230,7 @@ describe('ralph-routes', () => {
       });
       expect(res.statusCode).toBe(200);
       const body = JSON.parse(res.body);
-      expect(body.success).toBe(true);
+      expect(body).toEqual({});
       expect(tracker.resetCircuitBreaker).toHaveBeenCalled();
     });
 
diff --git a/test/routes/respawn-routes.test.ts b/test/routes/respawn-routes.test.ts
index c6867847..94095a7a 100644
--- a/test/routes/respawn-routes.test.ts
+++ b/test/routes/respawn-routes.test.ts
@@ -69,7 +69,9 @@ describe('respawn-routes', () => {
       });
       expect(res.statusCode).toBe(200);
       const body = JSON.parse(res.body);
-      expect(body.success).toBe(true);
+      // Handler now returns a bare payload; the uniform envelope wraps it to
+      // { success:true, data:{ config, active } } in production. At the route-handler
+      // layer the harness sees the bare return, so config/active stay top-level.
       expect(body.config).toBeNull();
       expect(body.active).toBe(false);
     });
@@ -88,7 +90,8 @@ describe('respawn-routes', () => {
       });
       expect(res.statusCode).toBe(200);
       const body = JSON.parse(res.body);
-      expect(body.success).toBe(true);
+      // Handler returns a bare { config, active } payload (wrapped under data by the
+      // uniform envelope in production); the harness sees the bare return.
       expect(body.active).toBe(true);
       expect(body.config.idleTimeoutMs).toBe(5000);
     });
@@ -121,7 +124,11 @@ describe('respawn-routes', () => {
       });
       expect(res.statusCode).toBe(200);
       const body = JSON.parse(res.body);
-      expect(body.success).toBe(true);
+      // Handler returns a bare {} on success; the uniform envelope wraps it to
+      // { success:true, data:{} } in production. At the route-handler layer the
+      // harness sees the bare return, so success is signalled by the 200 + empty
+      // body plus the side effects asserted below.
+      expect(body).toEqual({});
       expect(mockController.stop).toHaveBeenCalled();
       expect(harness.ctx.respawnControllers.has(harness.ctx._sessionId)).toBe(false);
       expect(harness.ctx.broadcast).toHaveBeenCalledWith('respawn:stopped', {
@@ -192,7 +199,9 @@ describe('respawn-routes', () => {
       });
       expect(res.statusCode).toBe(200);
       const body = JSON.parse(res.body);
-      expect(body.success).toBe(true);
+      // Handler returns a bare { config } payload (wrapped under data by the uniform
+      // envelope in production); the harness sees the bare return.
+      expect(body.config).toBeDefined();
       expect(mockController.updateConfig).toHaveBeenCalled();
       expect(harness.ctx.broadcast).toHaveBeenCalledWith(
         'respawn:configUpdated',
@@ -208,7 +217,9 @@ describe('respawn-routes', () => {
       });
       expect(res.statusCode).toBe(200);
       const body = JSON.parse(res.body);
-      expect(body.success).toBe(true);
+      // Handler returns a bare { config } payload (wrapped under data by the uniform
+      // envelope in production); the harness sees the bare return.
+      expect(body.config).toBeDefined();
       expect(harness.ctx.mux.updateRespawnConfig).toHaveBeenCalled();
     });
   });
diff --git a/test/routes/scheduled-routes.test.ts b/test/routes/scheduled-routes.test.ts
index bd1f3b5e..b9e532f4 100644
--- a/test/routes/scheduled-routes.test.ts
+++ b/test/routes/scheduled-routes.test.ts
@@ -102,7 +102,9 @@ describe('scheduled-routes', () => {
       });
       expect(res.statusCode).toBe(200);
       const body = JSON.parse(res.body);
-      expect(body.success).toBe(true);
+      // Handler returns a bare { run } now; the uniform envelope wraps it to
+      // { success:true, data:{ run } } in production. At the route-handler layer
+      // the harness sees the bare return, so assert body.run directly.
       expect(body.run.id).toBe('new-run');
     });
 
@@ -169,7 +171,9 @@ describe('scheduled-routes', () => {
       });
       expect(res.statusCode).toBe(200);
       const body = JSON.parse(res.body);
-      expect(body.success).toBe(true);
+      // Bare { run } return (envelope-wrapped to { success:true, data:{ run } }
+      // in production; harness sees the bare return).
+      expect(body.run).toBeDefined();
       // Should default to 60 minutes
       expect(harness.ctx.startScheduledRun).toHaveBeenCalledWith('test', expect.any(String), 60);
     });
@@ -200,7 +204,9 @@ describe('scheduled-routes', () => {
       });
       expect(res.statusCode).toBe(200);
       const body = JSON.parse(res.body);
-      expect(body.success).toBe(true);
+      // Handler returns a bare {} on success; the uniform envelope wraps it to
+      // { success:true, data:{} } in production. The harness sees the bare return.
+      expect(body).toEqual({});
       expect(harness.ctx.stopScheduledRun).toHaveBeenCalledWith('run-to-delete');
     });
 
diff --git a/test/routes/session-routes.test.ts b/test/routes/session-routes.test.ts
index b2cf213c..76eaad61 100644
--- a/test/routes/session-routes.test.ts
+++ b/test/routes/session-routes.test.ts
@@ -3,10 +3,22 @@
  *
  * Uses app.inject() (Fastify's built-in test helper) — no real HTTP ports needed.
  * Port: N/A (app.inject doesn't open ports)
+ *
+ * These tests assert the UNIFORM response envelope (stable HTTP contract):
+ *   success -> 2xx, { success: true, data: <payload> }
+ *   error   -> 4xx/5xx, { success: false, error, errorCode }
+ * The production server applies this via a preSerialization hook (server.ts).
+ * The shared route harness doesn't install it, so we build a local harness here
+ * that mirrors production: the same preSerialization envelope hook + the shared
+ * route error handler, so assertions match the real wire format.
  */
 
 import { describe, it, expect, beforeEach, afterEach, vi } from 'vitest';
-import { createRouteTestHarness, type RouteTestHarness } from './_route-test-utils.js';
+import Fastify, { type FastifyInstance } from 'fastify';
+import fastifyCookie from '@fastify/cookie';
+import { createMockRouteContext, type MockRouteContext } from '../mocks/index.js';
+import { installRouteErrorHandler } from '../../src/web/route-error-handler.js';
+import { ApiErrorCode, httpStatusForErrorCode } from '../../src/types.js';
 
 // Mock execFile so the send-key route's `tmux` invocation is observable (not run for real).
 const { execFile } = vi.hoisted(() => ({ execFile: vi.fn() }));
@@ -17,11 +29,55 @@ vi.mock('node:child_process', async (orig) => {
 
 import { registerSessionRoutes } from '../../src/web/routes/session-routes.js';
 
+interface LocalHarness {
+  app: FastifyInstance;
+  ctx: MockRouteContext;
+}
+
+/**
+ * Build a Fastify instance that mirrors production's uniform-envelope behavior
+ * (server.ts preSerialization hook) so the test wire format matches the contract:
+ * bare payloads become { success: true, data }, and { success:false } error
+ * envelopes get the conventional HTTP status from their errorCode.
+ */
+async function createEnvelopeHarness(
+  registerFn: (app: FastifyInstance, ctx: MockRouteContext) => void
+): Promise<LocalHarness> {
+  const app = Fastify({ logger: false });
+  await app.register(fastifyCookie);
+
+  const ctx = createMockRouteContext();
+  registerFn(app, ctx);
+
+  // Mirror production uniform response envelope (server.ts).
+  app.addHook('preSerialization', (req, reply, payload: unknown, done) => {
+    if (!req.url.startsWith('/api')) return done(null, payload);
+    if (payload === null || typeof payload !== 'object') return done(null, payload);
+    if (Buffer.isBuffer(payload) || typeof (payload as { pipe?: unknown }).pipe === 'function') {
+      return done(null, payload);
+    }
+    const p = payload as { success?: unknown; errorCode?: unknown };
+    if (p.success === false) {
+      if (reply.statusCode === 200 && typeof p.errorCode === 'string') {
+        reply.code(httpStatusForErrorCode(p.errorCode as ApiErrorCode));
+      }
+      return done(null, payload);
+    }
+    if (p.success === true) return done(null, payload);
+    return done(null, { success: true, data: payload });
+  });
+
+  installRouteErrorHandler(app);
+  await app.ready();
+
+  return { app, ctx };
+}
+
 describe('session-routes', () => {
-  let harness: RouteTestHarness;
+  let harness: LocalHarness;
 
   beforeEach(async () => {
-    harness = await createRouteTestHarness(registerSessionRoutes);
+    harness = await createEnvelopeHarness(registerSessionRoutes);
   });
 
   afterEach(async () => {
@@ -73,15 +129,15 @@ describe('session-routes', () => {
       const res = await harness.app.inject({ method: 'GET', url: '/api/sessions' });
       expect(res.statusCode).toBe(200);
       const body = JSON.parse(res.body);
-      expect(Array.isArray(body)).toBe(true);
-      expect(body).toHaveLength(1);
+      expect(Array.isArray(body.data)).toBe(true);
+      expect(body.data).toHaveLength(1);
     });
 
     it('returns empty array when no sessions', async () => {
       harness.ctx.sessions.clear();
       const res = await harness.app.inject({ method: 'GET', url: '/api/sessions' });
       expect(res.statusCode).toBe(200);
-      expect(JSON.parse(res.body)).toEqual([]);
+      expect(JSON.parse(res.body).data).toEqual([]);
     });
   });
 
@@ -95,7 +151,7 @@ describe('session-routes', () => {
       });
       expect(res.statusCode).toBe(200);
       const body = JSON.parse(res.body);
-      expect(body.id).toBe(harness.ctx._sessionId);
+      expect(body.data.id).toBe(harness.ctx._sessionId);
     });
 
     it('returns error for unknown session', async () => {
@@ -129,7 +185,7 @@ describe('session-routes', () => {
         method: 'DELETE',
         url: '/api/sessions/nonexistent',
       });
-      expect(res.statusCode).toBe(200);
+      expect(res.statusCode).toBe(404);
       const body = JSON.parse(res.body);
       expect(body.success).toBe(false);
     });
@@ -163,7 +219,7 @@ describe('session-routes', () => {
       expect(res.statusCode).toBe(200);
       const body = JSON.parse(res.body);
       expect(body.success).toBe(true);
-      expect(body.name).toBe('new-name');
+      expect(body.data.name).toBe('new-name');
       expect(harness.ctx.persistSessionState).toHaveBeenCalled();
       expect(harness.ctx.broadcast).toHaveBeenCalledWith('session:updated', expect.anything());
     });
@@ -192,7 +248,7 @@ describe('session-routes', () => {
       expect(res.statusCode).toBe(200);
       const body = JSON.parse(res.body);
       expect(body.success).toBe(true);
-      expect(body.color).toBe('blue');
+      expect(body.data.color).toBe('blue');
     });
 
     it('rejects invalid color', async () => {
@@ -201,7 +257,7 @@ describe('session-routes', () => {
         url: `/api/sessions/${harness.ctx._sessionId}/color`,
         payload: { color: 'neon-rainbow' },
       });
-      expect(res.statusCode).toBe(200);
+      expect(res.statusCode).toBe(400);
       const body = JSON.parse(res.body);
       expect(body.success).toBe(false);
     });
@@ -304,7 +360,7 @@ describe('session-routes', () => {
       });
       expect(res.statusCode).toBe(200);
       const body = JSON.parse(res.body);
-      expect(body.terminalBuffer).toBeDefined();
+      expect(body.data.terminalBuffer).toBeDefined();
     });
 
     it('returns error for unknown session', async () => {
@@ -361,7 +417,7 @@ describe('session-routes', () => {
         url: `/api/sessions/${harness.ctx._sessionId}/run`,
         payload: { prompt: 'test' },
       });
-      expect(res.statusCode).toBe(200);
+      expect(res.statusCode).toBe(409);
       const body = JSON.parse(res.body);
       expect(body.success).toBe(false);
     });
@@ -397,7 +453,7 @@ describe('session-routes', () => {
         method: 'POST',
         url: `/api/sessions/${harness.ctx._sessionId}/interactive`,
       });
-      expect(res.statusCode).toBe(200);
+      expect(res.statusCode).toBe(409);
       const body = JSON.parse(res.body);
       expect(body.success).toBe(false);
     });
@@ -423,7 +479,7 @@ describe('session-routes', () => {
         method: 'POST',
         url: `/api/sessions/${harness.ctx._sessionId}/shell`,
       });
-      expect(res.statusCode).toBe(200);
+      expect(res.statusCode).toBe(409);
       const body = JSON.parse(res.body);
       expect(body.success).toBe(false);
     });
@@ -512,8 +568,8 @@ describe('session-routes', () => {
       });
       expect(res.statusCode).toBe(200);
       const body = JSON.parse(res.body);
-      expect(body).toHaveProperty('sessions');
-      expect(Array.isArray(body.sessions)).toBe(true);
+      expect(body.data).toHaveProperty('sessions');
+      expect(Array.isArray(body.data.sessions)).toBe(true);
     });
 
     it('sessions have required fields', async () => {
@@ -522,7 +578,7 @@ describe('session-routes', () => {
         url: '/api/history/sessions',
       });
       const body = JSON.parse(res.body);
-      for (const session of body.sessions) {
+      for (const session of body.data.sessions) {
         expect(session).toHaveProperty('sessionId');
         expect(session).toHaveProperty('workingDir');
         expect(session).toHaveProperty('projectKey');
@@ -539,7 +595,7 @@ describe('session-routes', () => {
         url: '/api/history/sessions',
       });
       const body = JSON.parse(res.body);
-      const dates = body.sessions.map((s: { lastModified: string }) => new Date(s.lastModified).getTime());
+      const dates = body.data.sessions.map((s: { lastModified: string }) => new Date(s.lastModified).getTime());
       for (let i = 1; i < dates.length; i++) {
         expect(dates[i - 1]).toBeGreaterThanOrEqual(dates[i]);
       }
@@ -551,7 +607,7 @@ describe('session-routes', () => {
         url: '/api/history/sessions',
       });
       const body = JSON.parse(res.body);
-      expect(body.sessions.length).toBeLessThanOrEqual(50);
+      expect(body.data.sessions.length).toBeLessThanOrEqual(50);
     });
   });
 
@@ -572,7 +628,7 @@ describe('session-routes', () => {
       expect(res.statusCode).toBe(200);
       const body = JSON.parse(res.body);
       expect(body.success).toBe(true);
-      expect(body.session).toBeDefined();
+      expect(body.data.session).toBeDefined();
     });
 
     it('rejects invalid resumeSessionId format', async () => {
diff --git a/test/routes/system-routes.test.ts b/test/routes/system-routes.test.ts
index 18a664d1..e5d4f87d 100644
--- a/test/routes/system-routes.test.ts
+++ b/test/routes/system-routes.test.ts
@@ -140,7 +140,6 @@ describe('system-routes', () => {
       const res = await harness.app.inject({ method: 'GET', url: '/api/config' });
       expect(res.statusCode).toBe(200);
       const body = JSON.parse(res.body);
-      expect(body.success).toBe(true);
       expect(body.config).toBeDefined();
     });
   });
@@ -156,7 +155,7 @@ describe('system-routes', () => {
       });
       expect(res.statusCode).toBe(200);
       const body = JSON.parse(res.body);
-      expect(body.success).toBe(true);
+      expect(body.config).toBeDefined();
       expect(harness.ctx.store.setConfig).toHaveBeenCalled();
     });
 
@@ -179,7 +178,6 @@ describe('system-routes', () => {
       const res = await harness.app.inject({ method: 'GET', url: '/api/stats' });
       expect(res.statusCode).toBe(200);
       const body = JSON.parse(res.body);
-      expect(body.success).toBe(true);
       expect(body.stats).toBeDefined();
     });
   });
@@ -191,7 +189,6 @@ describe('system-routes', () => {
       const res = await harness.app.inject({ method: 'GET', url: '/api/token-stats' });
       expect(res.statusCode).toBe(200);
       const body = JSON.parse(res.body);
-      expect(body.success).toBe(true);
       expect(body.daily).toBeDefined();
       expect(body.totals).toBeDefined();
     });
@@ -230,7 +227,6 @@ describe('system-routes', () => {
       const res = await harness.app.inject({ method: 'POST', url: '/api/cleanup-state' });
       expect(res.statusCode).toBe(200);
       const body = JSON.parse(res.body);
-      expect(body.success).toBe(true);
       expect(body.cleanedSessions).toBe(0);
       expect(harness.ctx.store.cleanupStaleSessions).toHaveBeenCalled();
     });
@@ -266,7 +262,7 @@ describe('system-routes', () => {
       });
       expect(res.statusCode).toBe(200);
       const body = JSON.parse(res.body);
-      expect(body.success).toBe(true);
+      expect(body).toEqual({});
     });
 
     it('revokes a specific session token', async () => {
@@ -280,7 +276,6 @@ describe('system-routes', () => {
         payload: { sessionToken: 'tok-123' },
       });
       expect(res.statusCode).toBe(200);
-      expect(JSON.parse(res.body).success).toBe(true);
       expect(authSessions.has('tok-123')).toBe(false);
     });
 
@@ -333,8 +328,6 @@ describe('system-routes', () => {
         payload: { showSystemStats: true, subagentTrackingEnabled: false },
       });
       expect(res.statusCode).toBe(200);
-      const body = JSON.parse(res.body);
-      expect(body.success).toBe(true);
       expect(mockedWriteFile).toHaveBeenCalled();
     });
 
@@ -347,7 +340,7 @@ describe('system-routes', () => {
         payload: { showTokenCount: false },
       });
       expect(res.statusCode).toBe(200);
-      expect(JSON.parse(res.body).success).toBe(true);
+      expect(JSON.parse(res.body)).toEqual({});
 
       // Verify writeFile was called with merged content
       const writtenContent = JSON.parse(mockedWriteFile.mock.calls[0][1] as string);
@@ -377,7 +370,7 @@ describe('system-routes', () => {
         payload: { lastUsedCase: 'my-test-case' },
       });
       expect(res.statusCode).toBe(200);
-      expect(JSON.parse(res.body).success).toBe(true);
+      expect(JSON.parse(res.body)).toEqual({});
 
       const writtenContent = JSON.parse(mockedWriteFile.mock.calls[0][1] as string);
       expect(writtenContent.lastUsedCase).toBe('my-test-case');
@@ -439,7 +432,7 @@ describe('system-routes', () => {
         payload: { minimized: { 'agent-1': true }, open: ['agent-2'] },
       });
       expect(res.statusCode).toBe(200);
-      expect(JSON.parse(res.body).success).toBe(true);
+      expect(JSON.parse(res.body)).toEqual({});
       expect(mockedWriteFile).toHaveBeenCalled();
     });
 
@@ -450,7 +443,7 @@ describe('system-routes', () => {
         payload: { minimized: {}, open: [] },
       });
       expect(res.statusCode).toBe(200);
-      expect(JSON.parse(res.body).success).toBe(true);
+      expect(JSON.parse(res.body)).toEqual({});
     });
 
     it('rejects invalid minimized values', async () => {
@@ -496,7 +489,7 @@ describe('system-routes', () => {
         payload: { 'agent-1': 'session-abc' },
       });
       expect(res.statusCode).toBe(200);
-      expect(JSON.parse(res.body).success).toBe(true);
+      expect(JSON.parse(res.body)).toEqual({});
       expect(mockedWriteFile).toHaveBeenCalled();
     });
 
@@ -507,7 +500,7 @@ describe('system-routes', () => {
         payload: {},
       });
       expect(res.statusCode).toBe(200);
-      expect(JSON.parse(res.body).success).toBe(true);
+      expect(JSON.parse(res.body)).toEqual({});
     });
 
     it('rejects non-string values in parent map', async () => {
@@ -629,7 +622,6 @@ describe('system-routes', () => {
       const res = await harness.app.inject({ method: 'GET', url: '/api/session-lifecycle' });
       expect(res.statusCode).toBe(200);
       const body = JSON.parse(res.body);
-      expect(body.success).toBe(true);
       expect(body.entries).toEqual(mockEntries);
     });
 
@@ -754,7 +746,7 @@ describe('system-routes', () => {
         payload: { model: 'claude-3', temperature: 0.5 },
       });
       expect(res.statusCode).toBe(200);
-      expect(JSON.parse(res.body).success).toBe(true);
+      expect(JSON.parse(res.body)).toEqual({});
       expect(mockedWriteFile).toHaveBeenCalled();
 
       // Verify the written content contains modelConfig
@@ -771,7 +763,7 @@ describe('system-routes', () => {
         payload: { model: 'new-model' },
       });
       expect(res.statusCode).toBe(200);
-      expect(JSON.parse(res.body).success).toBe(true);
+      expect(JSON.parse(res.body)).toEqual({});
 
       const writtenContent = JSON.parse(mockedWriteFile.mock.calls[0][1] as string);
       expect(writtenContent.showCost).toBe(true);
@@ -972,7 +964,7 @@ describe('system-routes', () => {
 
       const res = await harness.app.inject({ method: 'POST', url: '/api/tunnel/qr/regenerate' });
       expect(res.statusCode).toBe(200);
-      expect(JSON.parse(res.body).success).toBe(true);
+      expect(JSON.parse(res.body)).toEqual({});
     });
   });
 });
diff --git a/test/routes/system-span-displays.test.ts b/test/routes/system-span-displays.test.ts
index 9a5359e5..6198fef6 100644
--- a/test/routes/system-span-displays.test.ts
+++ b/test/routes/system-span-displays.test.ts
@@ -65,7 +65,10 @@ describe('POST /api/system/span-displays', () => {
       headers: { host: 'localhost:5000' },
     });
     expect(res.statusCode).toBe(200);
-    expect(res.json()).toMatchObject({ success: true, url: 'http://localhost:5000' });
+    // Handler returns a bare { url } on success; the uniform envelope wraps it to
+    // { success:true, data:{ url } } in production. At the route-handler layer the
+    // harness sees the bare return, so we assert on body.url directly.
+    expect(res.json()).toMatchObject({ url: 'http://localhost:5000' });
     expect(spawnMock).toHaveBeenCalledTimes(1);
     const [cmd, args] = spawnMock.mock.calls[0] as [string, string[]];
     expect(cmd).toBe('bash');
diff --git a/test/scheduled-runs.test.ts b/test/scheduled-runs.test.ts
index b4c93484..67a6aab3 100644
--- a/test/scheduled-runs.test.ts
+++ b/test/scheduled-runs.test.ts
@@ -29,7 +29,7 @@ describe('Scheduled Runs API', () => {
       const response = await fetch(`${baseUrl}/api/scheduled`);
       const data = await response.json();
 
-      expect(Array.isArray(data)).toBe(true);
+      expect(Array.isArray(data.data)).toBe(true);
     });
   });
 
@@ -47,16 +47,16 @@ describe('Scheduled Runs API', () => {
       const data = await response.json();
 
       expect(data.success).toBe(true);
-      expect(data.run).toBeDefined();
-      expect(data.run.id).toBeDefined();
-      expect(data.run.prompt).toBe('echo test');
-      expect(data.run.durationMinutes).toBe(1);
-      expect(data.run.status).toBe('running');
+      expect(data.data.run).toBeDefined();
+      expect(data.data.run.id).toBeDefined();
+      expect(data.data.run.prompt).toBe('echo test');
+      expect(data.data.run.durationMinutes).toBe(1);
+      expect(data.data.run.status).toBe('running');
 
-      createdRuns.push(data.run.id);
+      createdRuns.push(data.data.run.id);
 
       // Stop the run immediately to avoid resource usage
-      await fetch(`${baseUrl}/api/scheduled/${data.run.id}`, { method: 'DELETE' });
+      await fetch(`${baseUrl}/api/scheduled/${data.data.run.id}`, { method: 'DELETE' });
     });
 
     it('should set correct timestamps', async () => {
@@ -74,12 +74,12 @@ describe('Scheduled Runs API', () => {
 
       const afterCreate = Date.now();
 
-      expect(data.run.startedAt).toBeGreaterThanOrEqual(beforeCreate);
-      expect(data.run.startedAt).toBeLessThanOrEqual(afterCreate);
-      expect(data.run.endAt).toBe(data.run.startedAt + 5 * 60 * 1000);
+      expect(data.data.run.startedAt).toBeGreaterThanOrEqual(beforeCreate);
+      expect(data.data.run.startedAt).toBeLessThanOrEqual(afterCreate);
+      expect(data.data.run.endAt).toBe(data.data.run.startedAt + 5 * 60 * 1000);
 
-      createdRuns.push(data.run.id);
-      await fetch(`${baseUrl}/api/scheduled/${data.run.id}`, { method: 'DELETE' });
+      createdRuns.push(data.data.run.id);
+      await fetch(`${baseUrl}/api/scheduled/${data.data.run.id}`, { method: 'DELETE' });
     });
 
     it('should initialize with zero completed tasks and cost', async () => {
@@ -93,13 +93,13 @@ describe('Scheduled Runs API', () => {
       });
       const data = await response.json();
 
-      expect(data.run.completedTasks).toBe(0);
-      expect(data.run.totalCost).toBe(0);
+      expect(data.data.run.completedTasks).toBe(0);
+      expect(data.data.run.totalCost).toBe(0);
       // Logs may have 1 or more entries depending on timing
-      expect(data.run.logs.length).toBeGreaterThanOrEqual(1);
+      expect(data.data.run.logs.length).toBeGreaterThanOrEqual(1);
 
-      createdRuns.push(data.run.id);
-      await fetch(`${baseUrl}/api/scheduled/${data.run.id}`, { method: 'DELETE' });
+      createdRuns.push(data.data.run.id);
+      await fetch(`${baseUrl}/api/scheduled/${data.data.run.id}`, { method: 'DELETE' });
     });
   });
 
@@ -115,15 +115,15 @@ describe('Scheduled Runs API', () => {
         }),
       });
       const createData = await createRes.json();
-      const runId = createData.run.id;
+      const runId = createData.data.run.id;
       createdRuns.push(runId);
 
       // Get the run
       const response = await fetch(`${baseUrl}/api/scheduled/${runId}`);
       const data = await response.json();
 
-      expect(data.id).toBe(runId);
-      expect(data.prompt).toBe('test get');
+      expect(data.data.id).toBe(runId);
+      expect(data.data.prompt).toBe('test get');
 
       await fetch(`${baseUrl}/api/scheduled/${runId}`, { method: 'DELETE' });
     });
@@ -148,7 +148,7 @@ describe('Scheduled Runs API', () => {
         }),
       });
       const createData = await createRes.json();
-      const runId = createData.run.id;
+      const runId = createData.data.run.id;
 
       // Delete/stop the run
       const response = await fetch(`${baseUrl}/api/scheduled/${runId}`, {
@@ -161,7 +161,7 @@ describe('Scheduled Runs API', () => {
       // Verify it's stopped
       const getRes = await fetch(`${baseUrl}/api/scheduled/${runId}`);
       const runData = await getRes.json();
-      expect(runData.status).toBe('stopped');
+      expect(runData.data.status).toBe('stopped');
     });
 
     it('should return error for non-existent run', async () => {
@@ -204,7 +204,9 @@ describe('Quick Run API', () => {
       });
       const data = await response.json();
 
-      expect(data.sessionId).toBeDefined();
+      // On success the payload is wrapped ({ success:true, data:{ sessionId, ... } });
+      // on failure the handler returns a bare { success:false, sessionId, error }.
+      expect(data.data?.sessionId ?? data.sessionId).toBeDefined();
       // Note: success/failure depends on Claude actually running
     });
 
diff --git a/test/session-cleanup.test.ts b/test/session-cleanup.test.ts
index 7118fb76..c5d760b8 100644
--- a/test/session-cleanup.test.ts
+++ b/test/session-cleanup.test.ts
@@ -60,14 +60,14 @@ describe('Session Cleanup', () => {
       expect(quickStartData.success).toBe(true);
 
       // Delete the session
-      const deleteRes = await fetch(`${baseUrl}/api/sessions/${quickStartData.sessionId}`, {
+      const deleteRes = await fetch(`${baseUrl}/api/sessions/${quickStartData.data.sessionId}`, {
         method: 'DELETE',
       });
       const deleteData = await deleteRes.json();
       expect(deleteData.success).toBe(true);
 
       // Verify session is gone
-      const getRes = await fetch(`${baseUrl}/api/sessions/${quickStartData.sessionId}`);
+      const getRes = await fetch(`${baseUrl}/api/sessions/${quickStartData.data.sessionId}`);
       const getData = await getRes.json();
       expect(getData.error).toContain('not found');
     });
@@ -87,7 +87,7 @@ describe('Session Cleanup', () => {
         });
         const data = await res.json();
         expect(data.success).toBe(true);
-        sessionIds.push(data.sessionId);
+        sessionIds.push(data.data.sessionId);
       }
 
       // Delete all sessions
@@ -103,7 +103,7 @@ describe('Session Cleanup', () => {
       const listRes = await fetch(`${baseUrl}/api/sessions`);
       const sessions = await listRes.json();
       for (const id of sessionIds) {
-        expect(sessions.find((s: any) => s.id === id)).toBeUndefined();
+        expect(sessions.data.find((s: any) => s.id === id)).toBeUndefined();
       }
     }, 60000); // Extended timeout for multi-session test
   });
@@ -129,19 +129,19 @@ describe('Session Cleanup', () => {
       expect(sessionData.success).toBe(true);
 
       // Start interactive with respawn
-      const interactiveRes = await fetch(`${baseUrl}/api/sessions/${sessionData.session.id}/interactive-respawn`, {
+      const interactiveRes = await fetch(`${baseUrl}/api/sessions/${sessionData.data.session.id}/interactive-respawn`, {
         method: 'POST',
       });
       const interactiveData = await interactiveRes.json();
       expect(interactiveData.success).toBe(true);
 
       // Verify respawn is running
-      const respawnRes = await fetch(`${baseUrl}/api/sessions/${sessionData.session.id}/respawn`);
+      const respawnRes = await fetch(`${baseUrl}/api/sessions/${sessionData.data.session.id}/respawn`);
       const respawnData = await respawnRes.json();
-      expect(respawnData.enabled).toBe(true);
+      expect(respawnData.data.enabled).toBe(true);
 
       // Delete session
-      await fetch(`${baseUrl}/api/sessions/${sessionData.session.id}`, {
+      await fetch(`${baseUrl}/api/sessions/${sessionData.data.session.id}`, {
         method: 'DELETE',
       });
 
@@ -149,10 +149,10 @@ describe('Session Cleanup', () => {
       await new Promise((resolve) => setTimeout(resolve, 500));
 
       // Verify respawn controller is cleaned up (enabled: false when controller doesn't exist)
-      const respawnAfterRes = await fetch(`${baseUrl}/api/sessions/${sessionData.session.id}/respawn`);
+      const respawnAfterRes = await fetch(`${baseUrl}/api/sessions/${sessionData.data.session.id}/respawn`);
       const respawnAfterData = await respawnAfterRes.json();
       // The respawn endpoint returns enabled: false when there's no controller
-      expect(respawnAfterData.enabled).toBe(false);
+      expect(respawnAfterData.data.enabled).toBe(false);
     });
   });
 
@@ -172,16 +172,16 @@ describe('Session Cleanup', () => {
       expect(createData.success).toBe(true);
 
       // Stop the scheduled run
-      const stopRes = await fetch(`${baseUrl}/api/scheduled/${createData.run.id}`, {
+      const stopRes = await fetch(`${baseUrl}/api/scheduled/${createData.data.run.id}`, {
         method: 'DELETE',
       });
       const stopData = await stopRes.json();
       expect(stopData.success).toBe(true);
 
       // Verify status is stopped
-      const getRes = await fetch(`${baseUrl}/api/scheduled/${createData.run.id}`);
+      const getRes = await fetch(`${baseUrl}/api/scheduled/${createData.data.run.id}`);
       const getData = await getRes.json();
-      expect(getData.status).toBe('stopped');
+      expect(getData.data.status).toBe('stopped');
     });
   });
 });
@@ -211,7 +211,7 @@ describe('Resource Management', () => {
     // Get initial session count (may have restored sessions from other tests)
     const initialRes = await fetch(`${baseUrl}/api/sessions`);
     const initialSessions = await initialRes.json();
-    const initialCount = initialSessions.length;
+    const initialCount = initialSessions.data.length;
 
     const iterations = 5;
     const createdSessionIds: string[] = [];
@@ -228,10 +228,10 @@ describe('Resource Management', () => {
       });
       const createData = await createRes.json();
       expect(createData.success).toBe(true);
-      createdSessionIds.push(createData.sessionId);
+      createdSessionIds.push(createData.data.sessionId);
 
       // Delete immediately
-      const deleteRes = await fetch(`${baseUrl}/api/sessions/${createData.sessionId}`, {
+      const deleteRes = await fetch(`${baseUrl}/api/sessions/${createData.data.sessionId}`, {
         method: 'DELETE',
       });
       const deleteData = await deleteRes.json();
@@ -250,11 +250,11 @@ describe('Resource Management', () => {
 
     // None of the sessions we created should still exist
     for (const sessionId of createdSessionIds) {
-      expect(sessions.find((s: { id: string }) => s.id === sessionId)).toBeUndefined();
+      expect(sessions.data.find((s: { id: string }) => s.id === sessionId)).toBeUndefined();
     }
 
     // Session count should be back to initial (or less if some restored sessions were cleaned up)
-    expect(sessions.length).toBeLessThanOrEqual(initialCount);
+    expect(sessions.data.length).toBeLessThanOrEqual(initialCount);
   });
 
   it('should clear terminal buffer after session stop', async () => {
@@ -274,18 +274,18 @@ describe('Resource Management', () => {
     await new Promise((resolve) => setTimeout(resolve, 2000));
 
     // Get terminal buffer before stop - may or may not have content depending on timing
-    const terminalRes = await fetch(`${baseUrl}/api/sessions/${createData.sessionId}/terminal`);
+    const terminalRes = await fetch(`${baseUrl}/api/sessions/${createData.data.sessionId}/terminal`);
     const terminalData = await terminalRes.json();
     // Just verify the property exists
-    expect(terminalData.terminalBuffer).toBeDefined();
+    expect(terminalData.data.terminalBuffer).toBeDefined();
 
     // Delete session
-    await fetch(`${baseUrl}/api/sessions/${createData.sessionId}`, {
+    await fetch(`${baseUrl}/api/sessions/${createData.data.sessionId}`, {
       method: 'DELETE',
     });
 
     // Session should be gone
-    const afterRes = await fetch(`${baseUrl}/api/sessions/${createData.sessionId}/terminal`);
+    const afterRes = await fetch(`${baseUrl}/api/sessions/${createData.data.sessionId}/terminal`);
     const afterData = await afterRes.json();
     expect(afterData.error).toContain('not found');
   });
diff --git a/test/session.test.ts b/test/session.test.ts
index e60c8317..6d8fe084 100644
--- a/test/session.test.ts
+++ b/test/session.test.ts
@@ -32,9 +32,9 @@ describe('Interactive Session Lifecycle', () => {
       const data = await response.json();
 
       expect(data.success).toBe(true);
-      expect(data.session.id).toBeDefined();
-      expect(data.session.workingDir).toBeDefined();
-      expect(data.session.status).toBe('idle');
+      expect(data.data.session.id).toBeDefined();
+      expect(data.data.session.workingDir).toBeDefined();
+      expect(data.data.session.status).toBe('idle');
     });
 
     it('should create session with custom working directory', async () => {
@@ -47,7 +47,7 @@ describe('Interactive Session Lifecycle', () => {
       const data = await response.json();
 
       expect(data.success).toBe(true);
-      expect(data.session.workingDir).toBe('/tmp/test');
+      expect(data.data.session.workingDir).toBe('/tmp/test');
     });
   });
 
@@ -60,14 +60,14 @@ describe('Interactive Session Lifecycle', () => {
         body: JSON.stringify({}),
       });
       const createData = await createRes.json();
-      const sessionId = createData.session.id;
+      const sessionId = createData.data.session.id;
 
       // Get the session
       const response = await fetch(`${baseUrl}/api/sessions/${sessionId}`);
       const data = await response.json();
 
-      expect(data.id).toBe(sessionId);
-      expect(data.status).toBeDefined();
+      expect(data.data.id).toBe(sessionId);
+      expect(data.data.status).toBeDefined();
     });
 
     it('should return error for non-existent session', async () => {
@@ -87,7 +87,7 @@ describe('Interactive Session Lifecycle', () => {
         body: JSON.stringify({}),
       });
       const createData = await createRes.json();
-      const sessionId = createData.session.id;
+      const sessionId = createData.data.session.id;
 
       // Delete the session
       const response = await fetch(`${baseUrl}/api/sessions/${sessionId}`, {
@@ -123,7 +123,7 @@ describe('Interactive Session Lifecycle', () => {
         body: JSON.stringify({}),
       });
       const createData = await createRes.json();
-      const sessionId = createData.session.id;
+      const sessionId = createData.data.session.id;
 
       // Get output
       const response = await fetch(`${baseUrl}/api/sessions/${sessionId}/output`);
@@ -145,14 +145,14 @@ describe('Interactive Session Lifecycle', () => {
         body: JSON.stringify({}),
       });
       const createData = await createRes.json();
-      const sessionId = createData.session.id;
+      const sessionId = createData.data.session.id;
 
       // Get terminal buffer
       const response = await fetch(`${baseUrl}/api/sessions/${sessionId}/terminal`);
       const data = await response.json();
 
-      expect(data).toHaveProperty('terminalBuffer');
-      expect(data).toHaveProperty('status');
+      expect(data.data).toHaveProperty('terminalBuffer');
+      expect(data.data).toHaveProperty('status');
     });
   });
 
@@ -165,7 +165,7 @@ describe('Interactive Session Lifecycle', () => {
         body: JSON.stringify({}),
       });
       const createData = await createRes.json();
-      const sessionId = createData.session.id;
+      const sessionId = createData.data.session.id;
 
       // Start interactive mode
       const response = await fetch(`${baseUrl}/api/sessions/${sessionId}/interactive`, {
@@ -195,7 +195,7 @@ describe('Interactive Session Lifecycle', () => {
         body: JSON.stringify({}),
       });
       const createData = await createRes.json();
-      const sessionId = createData.session.id;
+      const sessionId = createData.data.session.id;
 
       await fetch(`${baseUrl}/api/sessions/${sessionId}/interactive`, {
         method: 'POST',
@@ -225,7 +225,7 @@ describe('Interactive Session Lifecycle', () => {
         body: JSON.stringify({}),
       });
       const createData = await createRes.json();
-      const sessionId = createData.session.id;
+      const sessionId = createData.data.session.id;
 
       await fetch(`${baseUrl}/api/sessions/${sessionId}/interactive`, {
         method: 'POST',
diff --git a/test/sse-events.test.ts b/test/sse-events.test.ts
index 4ee745f8..ea3b1573 100644
--- a/test/sse-events.test.ts
+++ b/test/sse-events.test.ts
@@ -93,7 +93,7 @@ describe('SSE Events', () => {
 
       // Parse and check for init event
       const events = parseSSEEvents(receivedData);
-      const initEvent = events.find(e => e.event === 'init');
+      const initEvent = events.find((e) => e.event === 'init');
 
       expect(initEvent).toBeDefined();
       expect((initEvent?.data as any).sessions).toBeDefined();
@@ -109,7 +109,7 @@ describe('SSE Events', () => {
       // Start listening
       const fetchPromise = fetch(`${baseUrl}/api/events`, {
         signal: controller.signal,
-      }).then(async response => {
+      }).then(async (response) => {
         const reader = response.body?.getReader();
         if (reader) {
           try {
@@ -123,7 +123,7 @@ describe('SSE Events', () => {
       });
 
       // Give time to connect
-      await new Promise(resolve => setTimeout(resolve, 100));
+      await new Promise((resolve) => setTimeout(resolve, 100));
 
       // Create a session
       await fetch(`${baseUrl}/api/sessions`, {
@@ -133,15 +133,17 @@ describe('SSE Events', () => {
       });
 
       // Wait a bit for the event
-      await new Promise(resolve => setTimeout(resolve, 200));
+      await new Promise((resolve) => setTimeout(resolve, 200));
 
       // Stop listening
       controller.abort();
-      try { await fetchPromise; } catch {}
+      try {
+        await fetchPromise;
+      } catch {}
 
       // Parse events
       const events = parseSSEEvents(receivedData);
-      const sessionCreated = events.find(e => e.event === 'session:created');
+      const sessionCreated = events.find((e) => e.event === 'session:created');
 
       expect(sessionCreated).toBeDefined();
       expect((sessionCreated?.data as any).id).toBeDefined();
@@ -151,12 +153,13 @@ describe('SSE Events', () => {
   describe('GET /api/status', () => {
     it('should return full state', async () => {
       const response = await fetch(`${baseUrl}/api/status`);
-      const data = await response.json();
+      const body = await response.json();
 
-      expect(data).toHaveProperty('sessions');
-      expect(data).toHaveProperty('scheduledRuns');
-      expect(data).toHaveProperty('respawnStatus');
-      expect(data).toHaveProperty('timestamp');
+      expect(body.success).toBe(true);
+      expect(body.data).toHaveProperty('sessions');
+      expect(body.data).toHaveProperty('scheduledRuns');
+      expect(body.data).toHaveProperty('respawnStatus');
+      expect(body.data).toHaveProperty('timestamp');
     });
 
     it('should include active sessions', async () => {
@@ -168,9 +171,9 @@ describe('SSE Events', () => {
       });
 
       const response = await fetch(`${baseUrl}/api/status`);
-      const data = await response.json();
+      const body = await response.json();
 
-      expect(data.sessions.length).toBeGreaterThan(0);
+      expect(body.data.sessions.length).toBeGreaterThan(0);
     });
   });
 });
@@ -197,7 +200,7 @@ describe('SSE Event Types', () => {
       // Start listening
       const fetchPromise = fetch(`${baseUrl}/api/events`, {
         signal: controller.signal,
-      }).then(async response => {
+      }).then(async (response) => {
         const reader = response.body?.getReader();
         if (reader) {
           try {
@@ -211,7 +214,7 @@ describe('SSE Event Types', () => {
       });
 
       // Give time to connect
-      await new Promise(resolve => setTimeout(resolve, 100));
+      await new Promise((resolve) => setTimeout(resolve, 100));
 
       // Create a session
       const createRes = await fetch(`${baseUrl}/api/sessions`, {
@@ -222,23 +225,25 @@ describe('SSE Event Types', () => {
       const createData = await createRes.json();
 
       // Delete it
-      await fetch(`${baseUrl}/api/sessions/${createData.session.id}`, {
+      await fetch(`${baseUrl}/api/sessions/${createData.data.session.id}`, {
         method: 'DELETE',
       });
 
       // Wait for events
-      await new Promise(resolve => setTimeout(resolve, 200));
+      await new Promise((resolve) => setTimeout(resolve, 200));
 
       // Stop listening
       controller.abort();
-      try { await fetchPromise; } catch {}
+      try {
+        await fetchPromise;
+      } catch {}
 
       // Parse events
       const events = parseSSEEvents(receivedData);
-      const sessionDeleted = events.find(e => e.event === 'session:deleted');
+      const sessionDeleted = events.find((e) => e.event === 'session:deleted');
 
       expect(sessionDeleted).toBeDefined();
-      expect((sessionDeleted?.data as any).id).toBe(createData.session.id);
+      expect((sessionDeleted?.data as any).id).toBe(createData.data.session.id);
     });
   });
 
@@ -250,7 +255,7 @@ describe('SSE Event Types', () => {
       // Start listening
       const fetchPromise = fetch(`${baseUrl}/api/events`, {
         signal: controller.signal,
-      }).then(async response => {
+      }).then(async (response) => {
         const reader = response.body?.getReader();
         if (reader) {
           try {
@@ -264,7 +269,7 @@ describe('SSE Event Types', () => {
       });
 
       // Give time to connect
-      await new Promise(resolve => setTimeout(resolve, 100));
+      await new Promise((resolve) => setTimeout(resolve, 100));
 
       // Create a case
       const caseName = `test-sse-case-${Date.now()}`;
@@ -275,15 +280,17 @@ describe('SSE Event Types', () => {
       });
 
       // Wait for events
-      await new Promise(resolve => setTimeout(resolve, 200));
+      await new Promise((resolve) => setTimeout(resolve, 200));
 
       // Stop listening
       controller.abort();
-      try { await fetchPromise; } catch {}
+      try {
+        await fetchPromise;
+      } catch {}
 
       // Parse events
       const events = parseSSEEvents(receivedData);
-      const caseCreated = events.find(e => e.event === 'case:created');
+      const caseCreated = events.find((e) => e.event === 'case:created');
 
       expect(caseCreated).toBeDefined();
       expect((caseCreated?.data as any).name).toBe(caseName);
diff --git a/test/sse-subscription-filter.test.ts b/test/sse-subscription-filter.test.ts
index d81afaea..59511d92 100644
--- a/test/sse-subscription-filter.test.ts
+++ b/test/sse-subscription-filter.test.ts
@@ -159,7 +159,7 @@ describe('SSE Subscription Filtering', () => {
       body: JSON.stringify({ workingDir: '/tmp' }),
     });
     const createData = await createRes.json();
-    const sessionId = createData.session.id;
+    const sessionId = createData.data.session.id;
 
     // Wait for events to arrive
     await new Promise((resolve) => setTimeout(resolve, 300));
@@ -210,7 +210,7 @@ describe('SSE Subscription Filtering', () => {
       body: JSON.stringify({ workingDir: '/tmp' }),
     });
     const createData = await createRes.json();
-    const sessionId = createData.session.id;
+    const sessionId = createData.data.session.id;
 
     // Now connect SSE with the session filter
     const controller = new AbortController();
@@ -264,14 +264,14 @@ describe('SSE Subscription Filtering', () => {
       headers: { 'Content-Type': 'application/json' },
       body: JSON.stringify({ workingDir: '/tmp' }),
     });
-    const session1 = (await createRes1.json()).session;
+    const session1 = (await createRes1.json()).data.session;
 
     const createRes2 = await fetch(`${baseUrl}/api/sessions`, {
       method: 'POST',
       headers: { 'Content-Type': 'application/json' },
       body: JSON.stringify({ workingDir: '/tmp' }),
     });
-    const session2 = (await createRes2.json()).session;
+    const session2 = (await createRes2.json()).data.session;
 
     // Connect SSE subscribed ONLY to session1
     const controller = new AbortController();
@@ -331,14 +331,14 @@ describe('SSE Subscription Filtering', () => {
       headers: { 'Content-Type': 'application/json' },
       body: JSON.stringify({ workingDir: '/tmp' }),
     });
-    const session1 = (await createRes1.json()).session;
+    const session1 = (await createRes1.json()).data.session;
 
     const createRes2 = await fetch(`${baseUrl}/api/sessions`, {
       method: 'POST',
       headers: { 'Content-Type': 'application/json' },
       body: JSON.stringify({ workingDir: '/tmp' }),
     });
-    const session2 = (await createRes2.json()).session;
+    const session2 = (await createRes2.json()).data.session;
 
     // Connect SSE subscribed to both sessions
     const controller = new AbortController();
diff --git a/test/types.test.ts b/test/types.test.ts
index 99f64555..0f1b67f0 100644
--- a/test/types.test.ts
+++ b/test/types.test.ts
@@ -368,9 +368,9 @@ describe('types utility functions', () => {
       expect(ApiErrorCode.INTERNAL_ERROR).toBe('INTERNAL_ERROR');
     });
 
-    it('should have 6 error codes', () => {
+    it('should have 9 error codes', () => {
       const codes = Object.values(ApiErrorCode);
-      expect(codes).toHaveLength(6);
+      expect(codes).toHaveLength(9);
     });
   });
 });