# Execution Mode Policy

Every implementation task declares exactly one execution mode:

- `contract`: freezes planning, template, prompt, documentation, policy, or test-contract evidence without claiming runtime behavior changed.
- `runtime`: changes runtime behavior and must prove that change through Runtime Delta targets, runtime changed paths, and executable validation evidence.
- `hybrid`: changes both contract surfaces and runtime behavior, and must satisfy the runtime evidence gate for the runtime portion.

Contract work is first-class. It may close contract-only acceptance criteria when the implementation summary records frozen contract evidence and avoids runtime claims. Contract work cannot close acceptance criteria that still require runtime implementation.

Runtime and hybrid work are blocked until the closeout evidence includes:

- Runtime Delta target files from the task definition.
- Runtime changed paths in the implementation summary.
- Executable validation evidence for the changed behavior.
- A structured validation exception only when a planned validation command is blocked.

Review and validation findings are evidence-only. They do not authorize repair, metadata mutation, status updates, artifact creation, or inferred runtime acceptance without a separate explicit write-capable command.
