Coordinator

One session plans, briefs, routes and verifies. Workers do the work. Everything the coordinator knows lives in files, so a stopped session resumes from the ledger and a person can read the state at any time.

Rules of the pattern

• State in files. work/ledger.md holds every task: id, task, worker, state, artifact, verification, time. The coordinator writes it before it starts a worker and after it checks the result.
• The coordinator routes and verifies. It writes briefs and checks artifacts. It does the work itself only when the task is smaller than the brief would be.
• Briefs are complete. Each brief names the goal, the files the worker may touch, the files it must read, what done looks like, the checks to run, and what to report. A worker has none of the coordinator's context.
• Verify the artifact. A worker's report says what it did; the file, the commit or the test output shows it. A task moves to done only after the coordinator checks the artifact.
• Caps. At most two or three workers run at once. Workers never start workers of their own; every brief says so. Two workers never write the same files.
• Resume. Every long task leaves a marker in the ledger (state running, the worker, the start time). After a stop, read the ledger, check each running task's artifact, and set it to done, failed or queued before starting anything new.

Steps