workflow-stage-contract

Read the stage goal, owner, variant, and execution mode from the StageContextPackage, then verify required evidence is present, fresh, and trusted. Check worktree readiness and allowed actions before any write or tool operation, and return either a completed evidence envelope or a precise blocker.

An evidence envelope is the typed output a stage produces containing used evidence, assumptions, blockers, confidence, and handoff information. It makes each stage auditable by listing evidence with trust or hash values when available.

Missing required evidence produces a blocker with the exact key and the expected producer stage. Optional missing evidence does not block the workflow; the stage continues and records the assumption if the output remains safe.

A decision-gated question is created when an open question is classified as high or critical risk. Low-risk questions are resolved with a documented default and marked as an assumption instead of blocking the workflow.

The stage must not perform unrelated stages, overwrite evidence owned by another stage, or execute privileged actions directly. Privileged operations are requested through the approved action pipeline, and writes stay within the assigned worktree.