Proof Publisher MCP

A deliberately small TypeScript MCP server that publishes commit-bound proof summaries to an HTTPS webhook. The project exists to make one consequential external write easy to inspect, test, and place behind an authority boundary.

Consequential boundary

The publish_proof MCP tool calls ProofPublishingService.publish(). The service validates and normalizes the exact target, repository, full commit SHA, and summary, then calls ProofPublisher.send(action). The live implementation's only external write is the fetch() POST inside HttpWebhookProofPublisher.send().

MCP publish_proof
  -> normalize exact action + SHA-256 fingerprint
  -> ProofPublisher.send(action)       <-- authority seam
  -> fetch(allowed HTTPS origin)        <-- consequential provider call

Writes fail closed unless ENABLE_WEBHOOK_WRITES=true, and even then the target must match WEBHOOK_ALLOWED_ORIGIN. Tests inject a recording provider; they do not make network calls.

Related MCP server: agent-gate

Run the checks

npm install
npm run ci

Run the MCP server

Read-only/fail-closed mode is the default:

npm run build
npm start

To permit a real webhook write, an operator must explicitly configure both the write switch and the only allowed origin:

ENABLE_WEBHOOK_WRITES=true \
WEBHOOK_ALLOWED_ORIGIN=https://hooks.example.com \
npm start

No credentials are stored in this repository. The project is intentionally small so future approval logic can bind to the normalized action immediately before the provider runs, without moving validation or external I/O into the authority layer.