feat(files): preview text files from outside the workspace, and stop routing them at a viewer that cannot read them

A .json/.log/.yaml/code path outside the session workspace was refused as an
unsupported type, and clicking one in the terminal made it worse: text goes to
the log viewer, which spawns `tail -f` and allows only the workspace, /var/log
and ~/logs, so it answered "Path must be within working directory or allowed
log directories" while the same path clicked in the response viewer previewed
fine. Two surfaces, two answers, for a file the session can already cat.

- TEXT_ATTACHMENT_EXTENSIONS IS EDITABLE_EXTENSIONS (config/file-editing.ts),
  not a second curated list that would drift from it. The rule reads: if the
  viewer would open a file for editing inside the workspace, the same file
  outside it can be read. The suffix was never the confidentiality gate here,
  the path guard is (sensitive-file blocklist, /root and /etc trees, realpath
  before the check), and it still runs on every registration.
- Widening what can be READ must not widen what can RUN. html/htm join svg in
  serveRawFile's download-only branch, so markup is never served with a
  renderable type on our own origin; other text goes out as inert
  text/plain; charset=utf-8 with nosniff, matching what the path picker does.
  The preview reads through fetch(), which ignores the disposition, so a
  clicked .html still shows its source.
- ~/.codeman*/state.json joins isSensitivePath. It persists
  SessionState.envOverrides and the env allowlist admits key-shaped names
  (GEMINI_API_KEY, CLAUDE_CODE_*), so it can hold a live credential. Same
  treatment as hook-secret and users.json, and the rest of the tree stays
  attachable.
- The terminal sends an out-of-workspace path to the preview instead of the log
  viewer. In-workspace text keeps the tail viewer, which is the point of it, and
  file-stream-manager's allowlist is untouched: no `tail -f` on arbitrary host
  paths.
- The by-id text preview is bounded like the workspace one: a Range request for
  the first 512KB (a real partial read, not a discarded 50MB download) plus a
  500-line cap, with the footer saying so.

Verified on an isolated instance: a 1.1MB external log opens in ~1.8s showing
500 lines with "showing first 500 lines" in the footer; json, yaml and code
preview; an .html carrying a script tag renders as source and does not execute;
.svg is still refused; a terminal click on an external .yaml opens the preview
with no log viewer and no attachment card; an in-workspace .log still opens the
streaming tail viewer.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

CLAUDE.md

@@ -230,7 +230,7 @@ Codeman is a Claude Code session manager with web interface and autonomous Ralph
 
 **Attachments** (live external document references; all wiring in `file-routes.ts`): a **registry** maps a stable `attachmentId` to a realpath-resolved, extension-allowlisted absolute path, so browser requests never carry arbitrary absolute paths. ⚠️ The **magic-link scanner** (`codeman://attach?...` in terminal output) is **prompt-injectable**, so its scan path is force-confined to the session workspace; a hostile prompt could otherwise exfiltrate arbitrary host files over SSE. The security gate is an extension **allowlist**, not a blocklist. `document-conversion-limiter.ts` caps converter spawns globally: without it, N large docs detected at once fork N multi-minute processes, which is a resource-exhaustion vector. → [architecture-invariants#attachments](docs/architecture-invariants.md#attachments)
 
-**File-path links (terminal + chat)**: a path an agent prints is clickable on BOTH surfaces and opens the file-preview overlay. ⚠️ ONE pattern (`FILE_PATH_LINK_PATTERN` / `absoluteFilePathPattern()` in constants.js) feeds the xterm link provider AND the response viewer's `_linkifyFilePaths()`; a fresh instance per call, since `lastIndex` is per-object state. The chat linkifier walks TEXT NODES with DOM APIs (the source is model output; never rebuild sanitized markup as a string) and skips subtrees already inside an `<a>`. ⚠️ **An out-of-workspace path is served through the ATTACHMENT routes, not the file routes** — `file-content`/`file-raw` are workspace-confined and 404 exactly the paths agents print most (a `/tmp` capture, Claude's scratchpad), so `openFilePreview()` registers such a path via `POST /api/sessions/:id/attachments` with **`notify: false`** (suppresses only the `attachment:detected` broadcast — same guard, same routes; without it every click also popped a card announcing the file already on screen) and renders by id. The click is an explicit action on the explicit, Origin-guarded route, which is what distinguishes it from the force-confined magic-link scanner. ⚠️ **Media extensions are single-sourced** (`VIDEO_ATTACHMENT_EXTENSIONS`/`AUDIO_ATTACHMENT_EXTENSIONS` in `attachment-registry.ts`, imported by `file-content`'s classification) so a clip plays the same in or out of the workspace; a player needs all THREE of allowlist + a real `MIME_TYPES` entry (octet-stream renders a dead player) + the range-aware body. The image-watcher keeps its own narrow detection list, so this does not card every video an agent writes. → [architecture-invariants#file-path-links-terminal--response-viewer](docs/architecture-invariants.md#file-path-links-terminal--response-viewer)
+**File-path links (terminal + chat)**: a path an agent prints is clickable on BOTH surfaces and opens the file-preview overlay. ⚠️ ONE pattern (`FILE_PATH_LINK_PATTERN` / `absoluteFilePathPattern()` in constants.js) feeds the xterm link provider AND the response viewer's `_linkifyFilePaths()`; a fresh instance per call, since `lastIndex` is per-object state. The chat linkifier walks TEXT NODES with DOM APIs (the source is model output; never rebuild sanitized markup as a string) and skips subtrees already inside an `<a>`. ⚠️ **An out-of-workspace path is served through the ATTACHMENT routes, not the file routes** — `file-content`/`file-raw` are workspace-confined and 404 exactly the paths agents print most (a `/tmp` capture, Claude's scratchpad), so `openFilePreview()` registers such a path via `POST /api/sessions/:id/attachments` with **`notify: false`** (suppresses only the `attachment:detected` broadcast — same guard, same routes; without it every click also popped a card announcing the file already on screen) and renders by id. The click is an explicit action on the explicit, Origin-guarded route, which is what distinguishes it from the force-confined magic-link scanner. ⚠️ **Media extensions are single-sourced** (`VIDEO_ATTACHMENT_EXTENSIONS`/`AUDIO_ATTACHMENT_EXTENSIONS` in `attachment-registry.ts`, imported by `file-content`'s classification) so a clip plays the same in or out of the workspace; a player needs all THREE of allowlist + a real `MIME_TYPES` entry (octet-stream renders a dead player) + the range-aware body. ⚠️ **`TEXT_ATTACHMENT_EXTENSIONS` IS `EDITABLE_EXTENSIONS`** (never a second list): if the viewer would edit it inside the workspace, it can be read outside. Widening READ must never widen RUN, so `html`/`htm` joined `svg` in `serveRawFile`'s download-only branch, other text goes out as inert `text/plain`+`nosniff`, and `~/.codeman*/state.json` joined `isSensitivePath` (it persists `envOverrides`, which can hold `GEMINI_API_KEY`). ⚠️ The terminal sends an **out-of-workspace** path to the preview instead of the log viewer (that one spawns `tail -f` and reaches only workspace + `/var/log` + `~/logs`); in-workspace text keeps the tail viewer and `file-stream-manager`'s allowlist is untouched. The image-watcher keeps its own narrow detection list, so none of this cards every file an agent writes. → [architecture-invariants#file-path-links-terminal--response-viewer](docs/architecture-invariants.md#file-path-links-terminal--response-viewer)
 
 **Filesystem path picker** (Link Existing "Browse" + the mobile keyboard's `📁 Path` key): lazy one-directory browsing via `GET /api/filesystem/browse`, with `GET /api/filesystem/preview` for the tapped file. Inserts the path **without** Enter, so the prompt is never submitted; the sibling `⌫ All` key clears only the unsent prompt and must never send the agent's `/clear`. ⚠️ This is a **second file-serving surface and inherits neither the attachment confinement nor its ownership scoping** — it allowlists Home, `CASES_DIR`, `/mnt/d` and `CODEMAN_FILE_PICKER_ROOTS`, blocks sensitive trees, and rejects symlink escapes **after** `realpath`. ⚠️ The optional `sessionId` is an ownership boundary that must be `canAccessOwned`-checked by hand (it does not go through `findSessionOrFail`), and in multi-user mode a non-admin gets only their own `userSpacePath` as a root: per-user spaces live INSIDE `homedir()`, so a `Home` root exposes every other user's workspace. Previews go through the same global conversion limiter, and Markdown/TXT/JSON are served as inert `text/plain`. → [architecture-invariants#filesystem-path-picker](docs/architecture-invariants.md#filesystem-path-picker)
 

docs/architecture-invariants.md

@@ -130,7 +130,11 @@ A file path an agent prints is a link on both surfaces it can appear on, and cli
 
 **The chat linkifier walks text nodes.** `_linkifyFilePaths()` builds anchors with `createElement`/`textContent` on the rendered subtree, never by rebuilding sanitized markup as a string — the source is model output. Subtrees already inside an `<a>` are skipped (marked autolinks URLs; a nested anchor would swallow the click), and the anchor's text is the path verbatim so "copy code" still yields what the agent printed. `test/response-viewer-file-links.test.ts` pins both properties.
 
-**Out-of-workspace paths go through the attachment routes, not the file routes.** `file-content`/`file-raw` resolve against `workingDir` and 404 anything that escapes it, which is correct and unchanged — but the paths agents most often print (a `/tmp` capture, Claude's own scratchpad, another checkout) are exactly that, so clicking one used to report "File not found" for a file sitting on disk. `openFilePreview()` now detects the case (`_isExternalPreviewPath`, a string compare for ROUTING only; the real decision stays server-side) and registers the path via `POST /api/sessions/:id/attachments` first, rendering by id. ⚠️ That registration passes `notify: false`, which suppresses ONLY the `attachment:detected` broadcast — the guard, the registry entry and the by-id routes are identical either way. Without it every click also popped an attachment card announcing the file already filling the screen. ⚠️ The click is an explicit user action on the **explicit, Origin-guarded** registration route, which is why it may cross the workspace boundary at all; the passive magic-link scanner stays force-confined. A type outside `SUPPORTED_ATTACHMENT_EXTENSIONS` (`.svg`, `.bmp`, `.json`, `.log`, code files) is refused with a message naming what IS previewable, rather than the registry's own policy term.
+**Out-of-workspace paths go through the attachment routes, not the file routes.** `file-content`/`file-raw` resolve against `workingDir` and 404 anything that escapes it, which is correct and unchanged — but the paths agents most often print (a `/tmp` capture, Claude's own scratchpad, another checkout) are exactly that, so clicking one used to report "File not found" for a file sitting on disk. `openFilePreview()` now detects the case (`_isExternalPreviewPath`, a string compare for ROUTING only; the real decision stays server-side) and registers the path via `POST /api/sessions/:id/attachments` first, rendering by id. ⚠️ That registration passes `notify: false`, which suppresses ONLY the `attachment:detected` broadcast — the guard, the registry entry and the by-id routes are identical either way. Without it every click also popped an attachment card announcing the file already filling the screen. ⚠️ The click is an explicit user action on the **explicit, Origin-guarded** registration route, which is why it may cross the workspace boundary at all; the passive magic-link scanner stays force-confined. A type outside `SUPPORTED_ATTACHMENT_EXTENSIONS` (`.svg`, `.bmp`) is refused with a message naming what IS previewable, rather than the registry's own policy term.
+
+⚠️ **The terminal routes an out-of-workspace path to the preview, not the log viewer.** The log viewer spawns `tail -f` and allows only the workspace, `/var/log` and `~/logs`, so an external `.log`/`.json`/code path answered `Path must be within working directory or allowed log directories` while the SAME path clicked in the response viewer previewed fine. `activate()` now checks `_isExternalPreviewPath` alongside `previewsInFileViewer`. In-workspace text keeps the tail viewer, which is the point of it (live follow); nothing widened `file-stream-manager`'s allowlist, so no `tail -f` is spawned on an arbitrary host path.
+
+**Text reuses the edit-mode allowlist; markup stays download-only.** `TEXT_ATTACHMENT_EXTENSIONS` IS `EDITABLE_EXTENSIONS` (`config/file-editing.ts`) rather than a second curated list that would drift from it: if the viewer would open a file for editing inside the workspace, the same file outside it can be read. The justification for widening is that the agent in the session can already `cat` any of these and the picker already previews them, so the suffix was never the confidentiality gate; the path guard is (sensitive-file blocklist, `/root` and `/etc` trees, realpath first). ⚠️ Two consequences had to be handled at the same time: `~/.codeman*/state.json` joined `isSensitivePath` (it persists `SessionState.envOverrides`, and the env allowlist admits key-shaped names like `GEMINI_API_KEY`, so it can hold a live credential), and `html`/`htm` joined `svg` in `serveRawFile`'s **download-only** branch so that widening what can be READ never widens what can RUN on our own origin. Text with no dedicated MIME entry goes out as inert `text/plain; charset=utf-8` + `nosniff`, matching the picker. The by-id text preview is bounded like the workspace one: a `Range` request for the first 512KB (a real partial read, not a discarded 50MB download) plus a 500-line cap, with the footer saying so.
 
 **Media is single-sourced across the two preview paths.** `VIDEO_ATTACHMENT_EXTENSIONS` / `AUDIO_ATTACHMENT_EXTENSIONS` live in `attachment-registry.ts` and are imported by `file-content`'s media classification, so a clip plays identically whether it is in the workspace or reached by id from outside it. They diverged first: the workspace path had its own inline sets and the registry allowlist had no media at all, so a video an agent wrote to `/tmp` was refused as an unsupported type while the same file inside the repo played. ⚠️ Three things have to line up for a player rather than a dead frame: the extension in the allowlist, a **real MIME entry** in `MIME_TYPES` (a `<video>` refuses to decode `application/octet-stream`, which presents as a player that renders and then does nothing), and the range-aware body (`serveRawFile` → `sendFileBody`) that makes the scrub bar work. `getAttachmentType()` returns the `video`/`audio` members of `AttachmentDetectedType` for them; the attachment card has no per-type CSS and its thumbnail falls back to the type label, since `generateFirstPageThumbnail` has no media branch and answers 204. ⚠️ The image-watcher keeps its OWN narrow detection list (`png/pdf/docx/pptx`), so this does not start popping cards for every video an agent writes.
 

src/attachment-registry.ts

@@ -11,6 +11,7 @@ import { realpathSync } from 'node:fs';
 import fs from 'node:fs/promises';
 import { basename, extname, isAbsolute } from 'node:path';
 import { isBlockedAttachmentPath, loadAttachmentGuardConfig } from './config/attachment-guard.js';
+import { EDITABLE_EXTENSIONS } from './config/file-editing.js';
 import { validateSessionFilePath } from './web/route-helpers.js';
 import type { AttachmentDetectedEvent, AttachmentDetectedType } from './types.js';
 
@@ -34,6 +35,22 @@ export const AUDIO_ATTACHMENT_EXTENSIONS: ReadonlySet<string> = new Set([
   'opus',
 ]);
 
+/**
+ * Plain-text extensions, REUSING the File Viewer's edit-mode allowlist rather
+ * than curating a second list that would drift from it. The rule reads: if the
+ * viewer would open that file for editing inside the workspace, the same file
+ * outside it can be read here. `svg` and `env` are absent from that list by
+ * design and stay absent here.
+ *
+ * Why widen at all: the agent in the session can already `cat` any of these,
+ * and every path-shaped surface (the picker, the workspace viewer) can already
+ * show them. Refusing a `.log` an agent just wrote to `/tmp` bought no
+ * confidentiality, it only made the click fail. The confidentiality gate is the
+ * path guard that still runs on every registration (sensitive-file blocklist,
+ * `/root` and `/etc` trees, realpath before the check), not the file's suffix.
+ */
+export const TEXT_ATTACHMENT_EXTENSIONS: ReadonlySet<string> = EDITABLE_EXTENSIONS;
+
 const SUPPORTED_ATTACHMENT_EXTENSIONS = new Set([
   'png',
   'jpg',
@@ -47,6 +64,7 @@ const SUPPORTED_ATTACHMENT_EXTENSIONS = new Set([
   'txt',
   ...VIDEO_ATTACHMENT_EXTENSIONS,
   ...AUDIO_ATTACHMENT_EXTENSIONS,
+  ...TEXT_ATTACHMENT_EXTENSIONS,
 ]);
 
 export type AttachmentSource = 'detected' | 'external';
@@ -135,7 +153,9 @@ export function getAttachmentType(extension: string): AttachmentDetectedType {
   if (normalized === 'pdf') return 'pdf';
   if (normalized === 'pptx') return 'presentation';
   if (normalized === 'md') return 'markdown';
-  if (normalized === 'txt') return 'text';
+  // Everything else in the text family reads as text, including code and
+  // config: the card and the preview both treat it as a plain-text file.
+  if (normalized === 'txt' || TEXT_ATTACHMENT_EXTENSIONS.has(normalized)) return 'text';
   return 'document';
 }
 

src/web/public/panels-ui.js

@@ -15,6 +15,11 @@
 
 const AWAY_DIGEST_LAST_VIEWED_KEY = 'codeman-away-digest-last-viewed';
 const FILE_BROWSER_SHOW_HIDDEN_KEY = 'codeman:fileBrowserShowHidden';
+// Bounds for the by-id text preview, mirroring what the workspace text preview
+// already does server-side (500 lines). The byte cap rides a Range request, so
+// a huge log is a partial read rather than a download the viewer throws away.
+const TEXT_PREVIEW_MAX_BYTES = 512 * 1024;
+const TEXT_PREVIEW_MAX_LINES = 500;
 const AWAY_DIGEST_SECTIONS = [
   ['needsAttention', 'Needs Attention'],
   ['completed', 'Completed'],
@@ -3284,7 +3289,7 @@ Object.assign(CodemanApp.prototype, {
       if (/unsupported/i.test(reason)) {
         const ext = (filePath.split('.').pop() || '').toLowerCase();
         return {
-          error: `Cannot preview .${ext} from outside the session workspace (images, video, audio, PDF, Office documents, Markdown and text only).`,
+          error: `Cannot preview .${ext} from outside the session workspace (images, video, audio, PDF, Office documents and text files only).`,
         };
       }
       return { error: reason };
@@ -3363,10 +3368,24 @@ Object.assign(CodemanApp.prototype, {
         bodyEl.innerHTML = `<iframe src="${escapeHtml(`${base}/preview`)}" title="${escapeHtml(filePath)}"></iframe>`;
       } else {
         try {
-          const res = await fetch(`${base}/raw`);
+          // Bounded like the workspace text preview: a Range for the first
+          // chunk (the route is range-aware, so this is a real partial read,
+          // not a 50MB download thrown away) and a line cap on top. An agent's
+          // log can be enormous, and rendering all of it into one <pre> is how
+          // you lock up the tab on the file you wanted to glance at.
+          const res = await fetch(`${base}/raw`, { headers: { Range: `bytes=0-${TEXT_PREVIEW_MAX_BYTES - 1}` } });
           if (!res.ok) throw new Error('Failed to load attachment');
           const text = await res.text();
-          bodyEl.innerHTML = `<pre><code>${escapeHtml(text)}</code></pre>`;
+          const clippedByBytes = res.status === 206 && text.length >= TEXT_PREVIEW_MAX_BYTES;
+          const lines = text.split('\n');
+          const clippedByLines = lines.length > TEXT_PREVIEW_MAX_LINES;
+          const shown = clippedByLines ? lines.slice(0, TEXT_PREVIEW_MAX_LINES).join('\n') : text;
+          bodyEl.innerHTML = `<pre><code>${escapeHtml(shown)}</code></pre>`;
+          this.filePreviewContent = shown;
+          if (clippedByLines || clippedByBytes) {
+            const note = clippedByLines ? `showing first ${TEXT_PREVIEW_MAX_LINES} lines` : 'showing the start of the file';
+            footerEl.textContent = `${footerEl.textContent} (${note})`;
+          }
         } catch (err) {
           bodyEl.innerHTML = `<div class="binary-message">Error: ${escapeHtml(err.message)}</div>`;
         }

src/web/public/terminal-ui.js

@@ -1457,7 +1457,16 @@ Object.assign(CodemanApp.prototype, {
               // already renders images, PDFs, documents and media inline — and it
               // now reaches files outside the workspace too, which is where an
               // agent's screenshots and scratchpad captures actually land.
-              if (previewsInFileViewer(text)) {
+              //
+              // Text goes to the log viewer, which follows a file that is still
+              // being written — but ONLY where it can actually read: it spawns
+              // `tail -f` and allows the workspace, /var/log and ~/logs, so an
+              // out-of-workspace path there answered "Path must be within
+              // working directory or allowed log directories" while the SAME
+              // path clicked in the response viewer previewed fine. The preview
+              // reads those through the guarded attachment routes, so external
+              // paths route there and the two surfaces agree.
+              if (previewsInFileViewer(text) || self._isExternalPreviewPath(text, self.activeSessionId)) {
                 self.openFilePreview(text, self.activeSessionId);
                 return;
               }

src/web/routes/file-routes.ts

@@ -30,6 +30,7 @@ import {
   buildFileThumbnailRoute,
   isSupportedAttachmentExtension,
   registerExternalAttachment,
+  TEXT_ATTACHMENT_EXTENSIONS,
   VIDEO_ATTACHMENT_EXTENSIONS,
   type AttachmentRecord,
 } from '../../attachment-registry.js';
@@ -193,10 +194,16 @@ async function serveRawFile(
       );
     return;
   }
-  if (download || extension === 'svg') {
+  // Markup is download-only: served with a renderable type on our own origin it
+  // would be stored XSS. SVG was always here; HTML/HTM join it now that the text
+  // family is servable, so widening what can be READ never widened what can RUN.
+  // The preview overlay reads these through `fetch()`, which ignores the
+  // disposition, so a clicked .html still shows its source.
+  const markupOnly = extension === 'svg' || extension === 'html' || extension === 'htm';
+  if (download || markupOnly) {
     reply.header(
       'Content-Type',
-      extension === 'svg' ? 'application/octet-stream' : MIME_TYPES[extension] || 'application/octet-stream'
+      markupOnly ? 'application/octet-stream' : MIME_TYPES[extension] || 'application/octet-stream'
     );
     reply.header('Content-Disposition', buildContentDisposition('attachment', fileName));
     reply.header('X-Content-Type-Options', 'nosniff');
@@ -204,6 +211,17 @@ async function serveRawFile(
     return;
   }
 
+  // Plain text with no dedicated MIME entry (code, config, logs, csv, xml) goes
+  // out as inert text/plain rather than the octet-stream fallback, matching what
+  // the path picker already does. Never a type the browser would execute.
+  if (!MIME_TYPES[extension] && TEXT_ATTACHMENT_EXTENSIONS.has(extension)) {
+    reply.header('Content-Type', 'text/plain; charset=utf-8');
+    reply.header('Content-Disposition', buildContentDisposition('inline', fileName));
+    reply.header('X-Content-Type-Options', 'nosniff');
+    sendFileBody(reply, resolvedPath, stat.size, rangeHeader);
+    return;
+  }
+
   reply.header('Content-Type', MIME_TYPES[extension] || 'application/octet-stream');
   reply.header('Content-Disposition', buildContentDisposition('inline', fileName));
   reply.header('X-Content-Type-Options', 'nosniff');

src/web/sensitive-path.ts

@@ -80,6 +80,12 @@ const SENSITIVE_PATTERNS: RegExp[] = [
   /\/\.claude\/\.credentials\.json$/,
   /\/\.codeman[^/]*\/hook-secret$/,
   /\/\.codeman[^/]*\/users\.json$/,
+  // Codeman's own state file. Named once `.json` became previewable outside the
+  // workspace: `SessionState.envOverrides` persists whatever the user set for a
+  // session, and the env allowlist admits key-shaped names (`GEMINI_API_KEY`,
+  // `CLAUDE_CODE_*`), so this file can hold a live credential. Same reasoning
+  // as the two entries above, and it leaves the rest of ~/.codeman attachable.
+  /\/\.codeman[^/]*\/state\.json$/,
 ];
 
 /**

test/routes/file-routes-attachment-path-guard.test.ts

@@ -438,6 +438,124 @@ describe('file-routes attachment path guard (COD-53)', () => {
     });
   });
 
+  // ===== Text family (code, config and logs outside the workspace) =====
+  // The agent in the session can already `cat` these, so refusing the click
+  // bought no confidentiality. The gate that matters is the path guard, which
+  // still runs, and markup must not become executable just because it is now
+  // readable.
+  describe('text attachments', () => {
+    it.each([
+      ['/tmp/run.log', 'log'],
+      ['/tmp/data.json', 'json'],
+      ['/tmp/conf/app.yaml', 'yaml'],
+      ['/tmp/src/index.ts', 'ts'],
+      ['/tmp/export.csv', 'csv'],
+    ])('registers %s as a text attachment', async (path, extension) => {
+      mockedStat.mockResolvedValue({ size: 40, isFile: () => true, mtimeMs: 5 } as never);
+      const res = await harness.app.inject({
+        method: 'POST',
+        url: `/api/sessions/${harness.ctx._sessionId}/attachments`,
+        payload: { path, notify: false },
+      });
+
+      expect(res.statusCode).toBe(200);
+      const body = JSON.parse(res.body);
+      expect(body.data.extension).toBe(extension);
+      expect(body.data.attachmentType).toBe('text');
+    });
+
+    it('serves a text file with no dedicated MIME as inert text/plain', async () => {
+      const content = Buffer.from('boot ok\nstarted\n');
+      mockedStat.mockResolvedValue({ size: content.length, isFile: () => true, mtimeMs: 5 } as never);
+      mockedCreateReadStream.mockReturnValue(Readable.from([content]) as never);
+
+      const reg = await harness.app.inject({
+        method: 'POST',
+        url: `/api/sessions/${harness.ctx._sessionId}/attachments`,
+        payload: { path: '/tmp/run.log', notify: false },
+      });
+      const rawRes = await harness.app.inject({
+        method: 'GET',
+        url: `/api/sessions/${harness.ctx._sessionId}/attachments/${JSON.parse(reg.body).data.attachmentId}/raw`,
+      });
+
+      expect(rawRes.statusCode).toBe(200);
+      expect(rawRes.headers['content-type']).toBe('text/plain; charset=utf-8');
+      expect(rawRes.headers['x-content-type-options']).toBe('nosniff');
+    });
+
+    it('keeps HTML download-only so readable never means executable', async () => {
+      // Serving markup with a renderable type on our own origin is stored XSS.
+      // The preview reads it through fetch(), which ignores the disposition, so
+      // a clicked .html still shows its source.
+      const content = Buffer.from('<script>alert(1)</script>');
+      mockedStat.mockResolvedValue({ size: content.length, isFile: () => true, mtimeMs: 5 } as never);
+      mockedCreateReadStream.mockReturnValue(Readable.from([content]) as never);
+
+      const reg = await harness.app.inject({
+        method: 'POST',
+        url: `/api/sessions/${harness.ctx._sessionId}/attachments`,
+        payload: { path: '/tmp/report.html', notify: false },
+      });
+      const rawRes = await harness.app.inject({
+        method: 'GET',
+        url: `/api/sessions/${harness.ctx._sessionId}/attachments/${JSON.parse(reg.body).data.attachmentId}/raw`,
+      });
+
+      expect(rawRes.headers['content-type']).toBe('application/octet-stream');
+      expect(String(rawRes.headers['content-disposition'])).toContain('attachment');
+    });
+
+    it('answers a byte range for text so a huge log is a partial read', async () => {
+      const content = Buffer.from('0123456789abcdef');
+      mockedStat.mockResolvedValue({ size: content.length, isFile: () => true, mtimeMs: 5 } as never);
+      mockedCreateReadStream.mockReturnValue(Readable.from([content.subarray(0, 8)]) as never);
+
+      const reg = await harness.app.inject({
+        method: 'POST',
+        url: `/api/sessions/${harness.ctx._sessionId}/attachments`,
+        payload: { path: '/tmp/big.log', notify: false },
+      });
+      const rawRes = await harness.app.inject({
+        method: 'GET',
+        url: `/api/sessions/${harness.ctx._sessionId}/attachments/${JSON.parse(reg.body).data.attachmentId}/raw`,
+        headers: { range: 'bytes=0-7' },
+      });
+
+      expect(rawRes.statusCode).toBe(206);
+      expect(rawRes.headers['content-range']).toBe(`bytes 0-7/${content.length}`);
+    });
+
+    it.each([
+      ['/home/someone/.config/gh/hosts.yml', 'forge token'],
+      ['/home/someone/project/.env.json', 'dotenv'],
+      ['/home/someone/.codeman/state.json', 'codeman state (can hold envOverrides secrets)'],
+      ['/home/someone/deploy/credentials.yaml', 'generic credentials'],
+      ['/etc/codeman/dump.log', 'blocked tree'],
+    ])('still refuses %s (%s) now that text is servable', async (path) => {
+      mockedStat.mockResolvedValue({ size: 40, isFile: () => true, mtimeMs: 5 } as never);
+      const res = await harness.app.inject({
+        method: 'POST',
+        url: `/api/sessions/${harness.ctx._sessionId}/attachments`,
+        payload: { path, notify: false },
+      });
+
+      expect(res.statusCode).toBe(403);
+    });
+
+    it('still refuses a type outside the family', async () => {
+      mockedStat.mockResolvedValue({ size: 40, isFile: () => true, mtimeMs: 5 } as never);
+      const res = await harness.app.inject({
+        method: 'POST',
+        url: `/api/sessions/${harness.ctx._sessionId}/attachments`,
+        payload: { path: '/tmp/drawing.svg', notify: false },
+      });
+
+      expect(res.statusCode).toBe(400);
+      expect(JSON.parse(res.body).error).toMatch(/unsupported/i);
+    });
+  });
+
   // ===== Quiet registration (click-to-preview) =====
   // The file-preview overlay registers a clicked out-of-workspace path to mint
   // an id it can render by. It is already putting the file on screen, so the

test/sensitive-path.test.ts

@@ -73,6 +73,12 @@ describe('isSensitivePath', () => {
       ['codeman hook secret', `${HOME}/.codeman/hook-secret`],
       ['codeman user table', `${HOME}/.codeman/users.json`],
       ['codeman hook secret on a named instance', `${HOME}/.codeman-beta/hook-secret`],
+      // state.json persists SessionState.envOverrides, and the env allowlist
+      // admits key-shaped names (GEMINI_API_KEY, CLAUDE_CODE_*), so it can hold
+      // a live credential. Named once .json became previewable from outside the
+      // workspace.
+      ['codeman state file', `${HOME}/.codeman/state.json`],
+      ['codeman state file on a named instance', `${HOME}/.codeman-beta/state.json`],
     ];
 
     it.each(blocked)('blocks the %s', (_label, path) => {
@@ -88,6 +94,7 @@ describe('isSensitivePath', () => {
       // The publish skill and the review-card loop attach from these trees, so
       // only their named secret members are blocked, never the whole tree.
       ['a codeman screenshot', `${HOME}/.codeman/screenshots/shot.png`],
+      ['a codeman lifecycle log', `${HOME}/.codeman/session-lifecycle.jsonl`],
       ['a claude transcript', `${HOME}/.claude/projects/proj/session.jsonl`],
       ['a claude team inbox', `${HOME}/.claude/teams/alpha/inboxes/bob.json`],
       // isUnderTree-style separator awareness: a sibling name that merely starts