mcp: RT-326 cleanup

[m4ttheweric]

Cleans up the follow-ups the docs lane and the #504 review found in the mattstack MCP server, so every tool says what it does and the two remaining gaps are closed.

Permissions (lib/setup/base-permissions.ts)

• Removes Bash(rt chat tail *), which matches no verb, from BASE_PERMISSIONS, its JSDoc and AGENTS.md
• Drops rt chat tail from rt skills check's kept-on-Bash forms (lib/skills/mcp-lint.ts) and rt skills audit's prompt

Descriptions

• rt_verb no longer calls itself read-only and names the writes agent-safe verbs make, including skills sync's pull, commit and push
• gate_ask points at the gate_answer tool instead of rt gate answer --by pane
• git_push and branch_sync state their real refusals, and that branch_sync pushes only when the reset or rebase changed the branch
• agentSafe JSDoc matches the AGENTS.md bar

Behavior

• Daemon chat:sign-out deletes the session's chat session file, on the no-presence path too
• herd_start refuses in a herd worker pane (HERD_JOB set), before any daemon call
• Adds a read-only whoami tool: session id, pane, the chat handle the chat_* tools act as, and herd identity

Docs

• AGENTS.md's tool roster names whoami-tool.ts
• website/docs/guides/mcp.mdx carries the new git_push and branch_sync wording, the herd_start worker refusal and a whoami entry

Verification: bun run test 11293 pass, 7 fail (flavor-takeover, setup-connect and logdy-config, all passing in isolation: 55/55); lib/mcp lib/daemon lib/setup 4181 pass; e2e/tests/mcp-serve.test.ts 6/6 against a fresh build; tsc, picker:check and repo purity clean.

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Summary by CodeRabbit

• New Features
  • Added an identity check that reports available session and herd details, with a sign-in hint when no chat session is found.
• Bug Fixes
  • Signing out now clears saved session data, including when no active presence is recorded.
  • Starting a herd from a worker pane is now refused.
• Documentation
  • Clarified Git sync and push behavior, refusal cases, and identity information available through MCP tools.
  • Updated guidance for answering form gates and clarified that agent-safe actions may have side effects.

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Reviewing files that changed from the base of the PR and between f7e0bae and 696debe.

📒 Files selected for processing (1)

• lib/daemon/__tests__/chat-handlers.test.ts

🚧 Files skipped from review as they are similar to previous changes (1)

• lib/daemon/tests/chat-handlers.test.ts

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📝 Walkthrough

Walkthrough

The MCP roster adds a whoami identity tool and rejects herd_start calls from worker panes. Chat sign-out deletes the session file. MCP tool descriptions, agent-safe guidance, baseline permissions, skill linting, tests, and documentation are also updated.

Changes

MCP tools

Layer / File(s)	Summary
Add and publish the whoami tool lib/mcp/whoami-tool.ts, lib/mcp/tools.ts, AGENTS.md, lib/mcp/__tests__/whoami-tool.test.ts, lib/mcp/__tests__/tools.test.ts, e2e/tests/mcp-serve.test.ts, website/docs/guides/mcp.mdx	whoami returns session, pane, chat, and herd details from the server environment and chat session file without a daemon call. The MCP roster and tool documentation include it, and tests cover its output and publication.
Reject herd creation from worker panes lib/mcp/herd-tools.ts, lib/mcp/__tests__/herd-tools.test.ts, website/docs/guides/mcp.mdx	herd_start returns IN_WORKER when HERD_JOB is set, before input validation or dependency calls. A test and the Herd guide reflect this behavior.
Update MCP tool instructions lib/mcp/tools.ts, lib/mcp/__tests__/tools.test.ts, lib/mcp/git-tools.ts, website/docs/guides/mcp.mdx	The gate_ask, rt_verb, git_push, and branch_sync descriptions provide revised instructions and refusal conditions. Tests and the MCP guide reflect the changes.

Chat sign-out

Layer / File(s)	Summary
Delete the session file during sign-out lib/daemon/handlers/chat.ts, lib/daemon/__tests__/chat-handlers.test.ts	chat:sign-out calls deleteChatSession before checking for a presence row. Tests cover file removal with and without a presence row and an unsafe session ID.

Agent-safe and shell permission guidance

Layer / File(s)	Summary
Revise agent-safe and shell permission guidance lib/command-tree.ts, AGENTS.md, commands/skills-audit.ts, lib/setup/base-permissions.ts, lib/setup/__tests__/base-permissions.test.ts, lib/setup/__tests__/steps-c.test.ts, lib/skills/mcp-lint.ts, lib/skills/__tests__/mcp-lint.test.ts	The agentSafe documentation describes eligible calls and path-flag requirements. Baseline permissions and skill linting remove rt chat tail; tests and guidance reflect these changes.

Priority: ⬇️ Low

Estimated code review effort: 3 (Moderate) | ~25 minutes

Change: Feature

Sequence Diagram(s)

sequenceDiagram
  participant MCPClient
  participant whoamiTool
  participant ProcessEnvironment
  participant WhoamiDeps_session
  MCPClient->>whoamiTool: call whoami
  whoamiTool->>ProcessEnvironment: read session, pane, and herd identifiers
  whoamiTool->>WhoamiDeps_session: look up chat session
  WhoamiDeps_session-->>whoamiTool: return session or null
  whoamiTool-->>MCPClient: return identity details

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Merge Risk: ⚪ Minimal · up to 696de

No actionable merge-blocking issue was established; this change is mergeable after normal checks.

Security Architecture Review

Security architecture risk: 🔵 Low · up to f7e0b

The new identity tool reports the current session rather than accepting a request for another session, and the herd change restricts worker actions. Sign-out cleanup improves the usual path, but its behavior when file deletion fails and the surrounding runtime access controls are not fully established.

Retained concerns
No architecture-level concerns identified.

Security review details

Security Blast Radius

• inferred — The new direct disclosure is limited in the inspected handler to the MCP server’s own session, pane, chat, and herd identity. The effective exposure of that server to callers was not established.

Trust Boundaries and Controls

• observed — herd_start rejects a process with HERD_JOB set before input validation, repository resolution, or the daemon start call. whoami derives identity from server-side state rather than an MCP argument.

Resilience and Maintainability Implications

• observed — The file-deletion helper suppresses errors, while the daemon’s no-presence sign-out path returns success after calling it. This limits what that success response proves about session-file cleanup.

Hardening Proposals

• proposed — If successful sign-out is intended to guarantee removal of the session-file identity, make deletion failure observable and define retry or recovery behavior for interruption between file deletion and presence sign-out.

🚥 Pre-merge checks | ✅ 3 | ❌ 1 | ❓ 1

❌ Failed checks (1 warning, 1 inconclusive)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 25.00% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 8 functions across 16 files.	Write docstrings for the functions missing them to satisfy the coverage threshold.
Title check	❓ Inconclusive	The title identifies the MCP area and the RT-326 work, but "cleanup" is too broad to describe the primary behavior, permission, and documentation changes.	Replace "cleanup" with a concise summary of the main change, such as "mcp: add whoami and tighten tool permissions".

✅ Passed checks (3 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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lib/daemon/__tests__/chat-handlers.test.ts

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at Module._compile (node:internal/modules/cjs/loader:1830:14)
at Object..js (node:internal/modules/cjs/loader:1961:10)
at Module.load (node:internal/modules/cjs/loader:1553:32)
at Module._load (node:internal/modules/cjs/loader:1355:12)
at wrapModuleLoad (node:internal/modules/cjs/loader:255:19)
at loadCJSModuleWithModuleLoad (node:internal/modules/esm/translators:326:3)
at ModuleWrap. (node:internal/modules/esm/translators:231:7)
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Actionable comments posted: 1

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Inline comments:
In @lib/daemon/__tests__/chat-handlers.test.ts:
- Line 1288: Update the traversal-test fixture around escapePath to use an
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📥 Commits

Reviewing files that changed from the base of the PR and between 14f9488 and f7e0bae.

📒 Files selected for processing (19)

• AGENTS.md
• commands/skills-audit.ts
• e2e/tests/mcp-serve.test.ts
• lib/command-tree.ts
• lib/daemon/__tests__/chat-handlers.test.ts
• lib/daemon/handlers/chat.ts
• lib/mcp/__tests__/herd-tools.test.ts
• lib/mcp/__tests__/tools.test.ts
• lib/mcp/__tests__/whoami-tool.test.ts
• lib/mcp/git-tools.ts
• lib/mcp/herd-tools.ts
• lib/mcp/tools.ts
• lib/mcp/whoami-tool.ts
• lib/setup/__tests__/base-permissions.test.ts
• lib/setup/__tests__/steps-c.test.ts
• lib/setup/base-permissions.ts
• lib/skills/__tests__/mcp-lint.test.ts
• lib/skills/mcp-lint.ts
• website/docs/guides/mcp.mdx

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• lib/skills/mcp-lint.ts

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