trialmatch-mcp-bridge

A local stdio↔HTTPS bridge for Claude Desktop (THI-882). Deliberately not the real MCP server — no tool logic here at all. It does PKCE + local-loopback login against Cognito, caches a refresh token, and relays every MCP call from Desktop to the AgentCore Gateway over HTTPS with Authorization: Bearer <token> attached. The actual tools live in ../src/trialmatch_criteria_mcp/, deployed to AgentCore Runtime behind that Gateway.

Setup

Published to PyPI — this is the recommended way to run it, no repo access or git credentials needed at all:

uvx trialmatch-mcp-bridge --login   # one-time interactive sign-in; opens your browser

This matters beyond convenience: some MCP hosts run their server subprocesses in a sandbox that can't reach your normal git credentials — confirmed live, Claude Desktop (an MSIX/Windows-Store packaged app) runs in an AppContainer that can't access the interactive user's gh-configured git credential helper, so a git+https:// dependency against this (private) repo fails there even though it works fine from a plain terminal on the same machine. A public PyPI package has no credential step to fail.

Alternative, if you're already working in a local clone of this repo:

cd bridge
uv sync
uv run trialmatch-mcp-bridge --login

Either way, this caches a refresh token at ~/.trialmatch-mcp/credentials.json (0600). Subsequent runs refresh silently — you shouldn't need --login again unless the refresh token itself expires or is revoked.

Claude Desktop / Claude Code configuration

Add to claude_desktop_config.json (Desktop) or .mcp.json (Code):

{
  "mcpServers": {
    "trialmatch-criteria": {
      "command": "uvx",
      "args": ["trialmatch-mcp-bridge"]
    }
  }
}

Or, from a local clone:

{
  "mcpServers": {
    "trialmatch-criteria": {
      "command": "uv",
      "args": ["run", "--directory", "/absolute/path/to/TrialMatch-Criteria-MCP/bridge", "trialmatch-mcp-bridge"]
    }
  }
}

(Or point command at the installed trialmatch-mcp-bridge console script directly if you've installed this package outside a uv-managed venv.)

Not Claude Code's built-in remote-MCP OAuth support (/mcp add <gateway-url> or .mcp.json's "type": "http" + oauth block) — that connects directly to the Gateway and lets Claude Code do its own OAuth against Cognito, which currently hits a known Claude Code bug (anthropics/claude-code#35846): Cognito's discovery document doesn't advertise code_challenge_methods_supported (it supports PKCE S256 fine, it just doesn't list it there), and Claude Code's token exchange breaks as a result. This bridge sidesteps that entirely by doing PKCE itself, confirmed working.

Publishing

Automatic, via .github/workflows/ci.yml's publish-bridge job — no manual version bump, no git tags, no stored PyPI token (uses PyPI's OIDC "Trusted Publishing"). On a merge to main that touches bridge/**: bumps the PATCH version (computed from PyPI's own current "latest", not from anything in this repo) and publishes it.

Gated behind the pypi GitHub Environment (repo Settings → Environments → pypi), which has a deployment-branch policy restricting it to main only — per PyPI's own Trusted Publishing guidance, a dedicated environment for the publishing workflow is "strongly encouraged, especially if your repository has maintainers with commit access who shouldn't have PyPI publishing access." (No pre-release/dev-version channel — deliberately kept to just this one path; testing a specific in-progress change is simpler done straight from a local clone, see Setup above, than by publishing and pinning a throwaway version.)

One-time setup (already done, noted here in case the project is ever re-created):

1. Create the pypi GitHub Environment with a deployment-branch policy restricting it to main (done via gh api repos/Third-Opinion/TrialMatch-Criteria-MCP/environments/pypi, no UI needed — see git history for the exact call).
2. A PyPI account with access registers a pending trusted publisher at https://pypi.org/manage/account/publishing/ for project trialmatch-mcp-bridge, owner Third-Opinion, repo TrialMatch-Criteria-MCP, workflow ci.yml, environment name pypi.

Test

uv run pytest
uv run ruff check . && uv run ruff format --check .
uv run mypy src

Unit tests mock the Cognito token endpoint and the loopback callback — no browser or real Cognito pool needed to run them. A real end-to-end test still needs an actual browser login once (--login), since PKCE Authorization Code flow is inherently interactive by design.