Bridge modes
Boundary modes are not only a test helper. They are the same routing model used by the Bridge for local/remote development.
Mode table
| Mode | Behavior |
|---|---|
| live | Call the real implementation / deployed boundary |
| mock | Serve contract-conformant fakes (examples / effect mocks) |
| bridge | Fork only the tagged session’s traffic to a local implementation; must pass contract check before activation |
| replay | Serve recorded outputs; no original dependency required |
| shadow | Candidate receives traffic; output compared and never returned to callers |
| fault | Inject failures for a session only |
Session scoping
Fault and bridge modes are session-tagged. Break a dependency for tyler/chaos without taking down production traffic for everyone else.
payments.fault({ message: "simulated outage", session: "tyler/chaos" });
await payments.call(charge, { session: "tyler/chaos" }); // fails for you
await payments.call(charge); // fine for othersContract gate on bridge activation
A bridge that would carry traffic must satisfy the BoundaryContract first. Failures surface as typed contract errors — not silent skew.
Recording
Recording stays on: interactions become specification-by-example traces and training material (with lane-origin events excluded from baseline promotion by default).