fix(mcp): no file text in sync errors, follow relocated config dirs, docs and Settings polish (#521 review)

Maintainer merge-time fixes for the MCP server sync (opt-in mcpSyncEnabled, synced, default OFF).

M1, parse errors echoed config text (secrets included) into the HTTP response and Settings:
smol-toml's TomlError carries a code frame of the offending lines and V8's JSON "Unexpected
token" errors quote source. Both catch sites now go through describeMcpSyncError(): a parse
failure is reported by line/column only ("not valid TOML (line 3, column 21)", "not valid
JSON"), an errno failure by Node's own message (code, syscall, path), the module's own
messages via a McpConfigError class, anything else as "unexpected error". Tests put a secret
on the broken line (TOML, both JSON message shapes, and a write refused at the re-parse that
would have quoted a copied server's env) and assert it is absent from the result and from the
route's response body; they fail against the old code.

M2, CODEX_HOME / CLAUDE_CONFIG_DIR / XDG_CONFIG_HOME were ignored, so a sync could create a
file the CLI never reads and report success: new optional registry field
capabilities.mcpConfig.relocation { envVar, path } (registry data, no id branch; schema
reuses the env-name and no-traversal path rules). Declared for claude (CLAUDE_CONFIG_DIR,
checked in the 2.1.289 binary), codex (CODEX_HOME), opencode (XDG_CONFIG_HOME) and gemini
(GEMINI_CLI_HOME, gemini-cli paths.ts); antigravity follows $HOME only (agy 1.1.12 has no
relocation var). Resolved from the server process env at call time: absolute moves the file,
empty means unset, anything else reports the target with the new status "skipped" plus the
reason and writes nothing. Dedupe is now by resolved file. When a caller overrides `home`
without passing `env`, process.env is not consulted, and the route tests clear those vars so
a CI runner's XDG_CONFIG_HOME can never aim a write outside the temp HOME.

M3, feature undocumented: CLAUDE.md Key Patterns paragraph (opt-in, admin-only, additive
only, backups, re-parse validation, 0600 for copied secrets, names-only responses with
position-only parse errors, capabilities.mcpConfig and relocation), a Settings-Reference row
in the wiki, and docs/cli-registry.md + docs/api-reference.md updated for relocation, the
"skipped" status and the error policy.

Nits:
- N1 Preview/Sync before Save: the UI remembers the saved value on open and says "Save
  settings to turn MCP sync on first" instead of calling the routes; the 403 message also
  says to turn it on and save.
- N2 non-admins in multi-user mode: _applyMcpSyncAdminGate() hides the whole MCP group, called
  from applyMcpSyncVisibility() and the codeman:me event like the CLI-management gate.
- N3 scope chip says "synced".
- N4 "(1 servers)" pluralised; the unsupported list only names installed CLIs (route test
  pins it with a per-test installed set).
- N5 McpSyncResult / McpSyncTargetResult moved to src/types/mcp-sync.ts (barrel export); only
  the route imported them, so no churn.

Verified with an isolated instance (throwaway HOME, own instance and tmux socket) and
Playwright: chip, save-first message, preview rendering and the admin gate.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

src/config/cli-registry/schema.ts

@@ -28,6 +28,14 @@ const envName = z
   .regex(/^[A-Z_][A-Z0-9_]*$/, 'env var name must be UPPER_SNAKE_CASE')
   .max(64);
 
+/** A relative file path with no traversal or odd characters (MCP sync writes to it). */
+const mcpRelativePath = z
+  .string()
+  .min(1)
+  .max(100)
+  .regex(/^[A-Za-z0-9._-]+(\/[A-Za-z0-9._-]+)*$/)
+  .refine((v) => !v.split('/').includes('..'), 'must not contain ..');
+
 /**
  * A shell-safe bare word: no space, quote, backtick, `$`, `;`, `&`, `|`, `<`, `>`, parens,
  * braces, newline or backslash. Every LITERAL in the launch spec (base command, flag names,
@@ -382,12 +390,7 @@ const capabilitiesSchema = z
     mcpConfig: z
       .object({
         // Home-relative, no traversal: sync writes to this path.
-        path: z
-          .string()
-          .min(1)
-          .max(100)
-          .regex(/^[A-Za-z0-9._-]+(\/[A-Za-z0-9._-]+)*$/)
-          .refine((v) => !v.split('/').includes('..'), 'must not contain ..'),
+        path: mcpRelativePath,
         // Every value must be a known McpConfigFormat (types.ts); mcp-sync.ts's dialect table is
         // keyed by the same type, so an adapter-less format fails to compile there.
         format: z.enum([
@@ -397,6 +400,9 @@ const capabilitiesSchema = z
           'opencode-json',
           'antigravity-json',
         ] as const satisfies readonly McpConfigFormat[]),
+        // The env var the CLI reads to move the file, and the path under it (same no-traversal
+        // rule: sync writes there too). Resolved from the server env at call time, never here.
+        relocation: z.object({ envVar: envName, path: mcpRelativePath }).strict().optional(),
       })
       .strict()
       .optional(),

src/config/cli-registry/stock.ts

@@ -307,7 +307,12 @@ const CLAUDE: CliEntry = {
       'CLAUDE_CONFIG_DIR',
     ],
     gates: { nameFlag: { minVersion: '2.1.224', failClosed: true } },
-    mcpConfig: { path: '.claude.json', format: 'claude-json' },
+    // claude reads `$CLAUDE_CONFIG_DIR/.claude.json` when that is set (checked in 2.1.289).
+    mcpConfig: {
+      path: '.claude.json',
+      format: 'claude-json',
+      relocation: { envVar: 'CLAUDE_CONFIG_DIR', path: '.claude.json' },
+    },
     // Custom Model Endpoint Profiles (docs/custom-model-endpoints-plan.md) — verified by hand against a real
     // llama.cpp server. Claude reads these at process start only, so switching requires a
     // respawn, never a live hot-swap.
@@ -488,7 +493,12 @@ const OPENCODE: CliEntry = {
     ...agentDefaults(),
     altScreen: 'strip-mux-only',
     echo: { policy: 'buffer', anchor: { kind: 'cursor' }, predictProfile: undefined },
-    mcpConfig: { path: '.config/opencode/opencode.json', format: 'opencode-json' },
+    // opencode's global config dir is xdg-basedir's `$XDG_CONFIG_HOME/opencode`.
+    mcpConfig: {
+      path: '.config/opencode/opencode.json',
+      format: 'opencode-json',
+      relocation: { envVar: 'XDG_CONFIG_HOME', path: 'opencode/opencode.json' },
+    },
     // Verified by hand against a real llama.cpp server. Reuses the SAME env var opencode's
     // own `env.configContentVar` already declares — the builder in custom-model-injection.ts
     // must merge into whatever opencode config Codeman would otherwise send, not clobber it.
@@ -632,7 +642,11 @@ const CODEX: CliEntry = {
     // `dangerouslyBypassApprovals` on the wire), so it is the one that would have caught a
     // regression; `schema.ts` now rejects a name that is not a declared param.
     privilegedParams: [{ param: 'bypassApprovals', clampTo: false }],
-    mcpConfig: { path: '.codex/config.toml', format: 'codex-toml' },
+    mcpConfig: {
+      path: '.codex/config.toml',
+      format: 'codex-toml',
+      relocation: { envVar: 'CODEX_HOME', path: 'config.toml' },
+    },
     // Verified by hand against a real llama.cpp server. Written to an isolated CODEX_HOME
     // so the user's real ~/.codex/config.toml is never touched.
     customModelInjection: {
@@ -734,7 +748,12 @@ const GEMINI: CliEntry = {
     // MATERIALIZE a config (not just touch an already-sent one) or a non-granted owner who
     // sends no geminiConfig at all would still get yolo for free.
     privilegedParams: [{ param: 'approvalMode', clampTo: 'auto_edit', materializeWhenAbsent: true }],
-    mcpConfig: { path: '.gemini/settings.json', format: 'gemini-json' },
+    // gemini-cli's `homedir()` returns `GEMINI_CLI_HOME` when set (packages/core/src/utils/paths.ts).
+    mcpConfig: {
+      path: '.gemini/settings.json',
+      format: 'gemini-json',
+      relocation: { envVar: 'GEMINI_CLI_HOME', path: '.gemini/settings.json' },
+    },
     // Web-researched, unverified — needs a restart to pick up (CLI reads these at process
     // start). Confirm the exact model-override env var name against the installed
     // gemini-cli version before shipping.
@@ -814,6 +833,7 @@ const ANTIGRAVITY: CliEntry = {
     // Like codex: an ABSENT config already defaults safe (no bypass flag), so only a
     // SENT config needs the flag forced off — nothing is materialized.
     privilegedParams: [{ param: 'dangerouslySkipPermissions', clampTo: false }],
+    // No relocation var: `agy` 1.1.12 resolves `~/.gemini/config` from $HOME only.
     mcpConfig: { path: '.gemini/config/mcp_config.json', format: 'antigravity-json' },
     // No known CLI/env/config mechanism — Antigravity's own docs describe a GUI-only
     // custom-endpoint setting and explicitly say it "cannot currently" become the core

src/config/cli-registry/types.ts

@@ -530,8 +530,15 @@ export interface CliCapabilities {
    * `path` is relative to the home directory. `format` names the file dialect the sync
    * adapter reads and writes. Absent = no known/verified MCP config file, so the CLI is
    * skipped by sync rather than guessed at.
+   *
+   * `relocation` names the env var the CLI itself reads to move that file (codex's
+   * `CODEX_HOME`, claude's `CLAUDE_CONFIG_DIR`, opencode's `XDG_CONFIG_HOME`). When the SERVER
+   * process env (what the CLIs Codeman spawns inherit) sets it to an absolute directory, the
+   * file is `<that dir>/<relocation.path>` instead; set to anything else, the target is
+   * reported `skipped` rather than written somewhere the CLI never reads. Absent = the file
+   * only follows `$HOME`.
    */
-  mcpConfig?: { path: string; format: McpConfigFormat };
+  mcpConfig?: { path: string; format: McpConfigFormat; relocation?: { envVar: string; path: string } };
   /**
    * How this CLI is pointed at a user-supplied custom OpenAI-compatible
    * endpoint (local, e.g. llama.cpp, or cloud, e.g. Azure AI Foundry) — the