A deterministic policy-as-code guardrail gate for pull requests: it reviews a diff, blocks on named rule violations (secret leak, SQL-injection, forbidden API, missing tests) with remediation, and seals a signed, offline-verifiable evidence record of the decision. Includes an in-browser "Tamper a finding" control that forges the sealed record and shows the gate catch it three independent ways (content hash, signature, decision-replay).
Fully offline & deterministic — no API keys, no network. 49 tests green.
cd app/backend
pip install fastapi uvicorn cryptography --break-system-packages # if needed
uvicorn sentinel.api:app --port 8000 # API + dashboard at http://127.0.0.1:8000/
cd app/backend && python3 -m pytest -q # 49 passed
Specs in specs/. Built on the open-source Agent Assurance Harness (Ed25519-signed, policy-as-code gate). A scoped proof-of-work demo — all scenarios use synthetic/invented data.