Change Contract

How a contract defines behavior, file scope, required proof, and the locked baseline.

The Change Contract is the structured source of obligations for an individual delivery. It makes change limits enforceable and links requirements to acceptance criteria and proof.

#What a strict contract represents

Specification: a versioned description of expected behavior.
Requirements and acceptance criteria: traceable links between intent and acceptance.
Change scope: source paths authorized to change.
Test scope: allowed paths for tests captured as proof.
Proof commands: commands and oracles validating development behavior.
Baseline lock: Git state identity and effective policy digest bound to the locked contract.

#Draft and lock

The newer workflow passes a schema-v5 draft to polis start, which produces a locked schema-v6 Change Contract. Compatibility with draft schema v3 to locked schema v4 remains available.

bash

polis start --repo /repo \
  --policy /outside/policy-v3.json \
  --contract /outside/draft-v5.json \
  --out /outside/locked-v6.json

The lock must be established on a clean Git baseline before implementation. Do not rewrite a locked contract to excuse changes that exceeded scope; establish a new legitimate baseline and lock when requirements change.

#Scope is executable

scope.allowed_paths constrains implementation changes. Captured test files must also fall within the designated test scope. Before creating Red tests:

bash

polis check-red-scope --repo /repo \
  --contract /outside/locked-v6.json \
  --path tests/feature_test.go

This accepts paths that do not yet exist, since it validates the proposal rather than file contents. The later capture checks the actual test-only delta.

#Optional commit intent

A schema-v5 draft may include a commit message bound into the locked contract and package. It only creates a commit when the consumer explicitly invokes apply --commit-mode prompt or auto.

#Authoritative schema reference

Contracts have precise serialization, size, validation, and migration rules. Do not treat a partial UI example as a production contract template. Refer to the V6 Specification, versioned schemas, and CLI for valid inputs.