fix(daemon): allow token-authenticated remote MCP clients

[Faiyajz]

What & why

Fixes #218.

Remote MCP clients configured with a valid bearer token were rejected when they sent a public or reverse-proxy
Host header. The MCP transport applied its loopback Host allowlist before bearer-token validation, which
conflicted with the documented token-authenticated remote deployment model.

This change makes the bearer token the authorization boundary for remote MCP traffic while retaining the
browser-origin protection that prevents browser-driven access.

Changes

• Permit token-authenticated MCP requests with non-loopback Host headers.
• Continue rejecting requests that include an Origin header in both open and token-authenticated modes.
• Retain the loopback Host allowlist when no API token is configured.
• Add regression coverage for valid and invalid bearer tokens with a remote Host.
• Update REST API and self-hosting documentation to describe the resulting policy accurately.

Testing

• Targeted daemon suite: tests/unit/daemon/http-server.test.ts (38/38)
• TypeScript check: tsc --noEmit
• Added regression tests for the changed authorization behavior
• Full npm test suite: attempted, but unrelated failures occurred in tests/unit/tools/find- similar.test.ts in this environment

Checklist

• Follows Conventional Commits
• Focused change with no unrelated refactoring
• I have read CONTRIBUTING.md and agree to its contribution terms

Summary by CodeRabbit

• Bug Fixes

  • Refined MCP request security checks to reject browser-originated requests consistently.
  • Improved bearer-token authentication behavior for remote MCP connections.
  • Preserved Host allowlisting protections when operating without token authentication.
  • Remote MCP clients using valid bearer tokens can now connect with their normal Host header.

• Documentation

  • Updated REST API and self-hosting guidance to reflect the revised MCP authentication and proxy behavior.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro Plus

Run ID: f7e556ed-adf1-4a8f-a9f6-085ce25bb4f4

📥 Commits

Reviewing files that changed from the base of the PR and between 180ac3d and 939fc09.

📒 Files selected for processing (4)

• docs/rest-api.md
• docs/self-hosting.md
• src/daemon/http-server.ts
• tests/unit/daemon/http-server.test.ts

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📝 Walkthrough

Walkthrough

MCP transport authentication now rejects browser-originated requests first, validates bearer tokens before Host checks in token mode, and retains loopback Host allowlisting in open mode. Tests and self-hosting documentation cover remote token-authenticated clients and the updated restrictions.

Changes

MCP transport authentication

Layer / File(s)	Summary
MCP guard ordering and documentation src/daemon/http-server.ts, docs/rest-api.md, docs/self-hosting.md	MCP requests reject Origin headers first, validate bearer tokens before Host checks in token mode, and apply the Host allowlist in open mode; related documentation reflects these rules.
MCP authentication test coverage tests/unit/daemon/http-server.test.ts	Tests cover open-mode Host rejection, valid token access with a remote Host, invalid token rejection, and shared MCP request setup.

Estimated code review effort: 3 (Moderate) | ~20 minutes

Suggested reviewers: knockoutez

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title is concise and accurately reflects the main change: allowing token-authenticated remote MCP clients.
Linked Issues check	✅ Passed	The code changes match #218 by checking bearer tokens before host allowlisting in token mode, while keeping origin blocking and open-mode host restrictions.
Out of Scope Changes check	✅ Passed	The docs and tests support the MCP auth fix and do not introduce unrelated scope.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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