Router contract changes
Read the nearest AGENTS.md for every touched subtree and
tools/agent/docs/change-surfaces.md for the affected contract.
Keep the request-facing entrypoint, isolated recipe, signal/projection inputs, decision or algorithm, and selected backend/plugin behavior consistent. Update canonical config, generated or schema-derived artifacts, and user-visible docs only where that contract changes.
Run make check first. Use make verify DOMAIN=<domain> for the affected
integration contract, or make verify PROFILE=<profile> when behavior crosses
the deployment boundary. A pure refactor does not need new E2E coverage.