Validate Contracts

HARD GATE — Do NOT deploy or migrate data without running validate-contracts first. Silent data divergence between system boundaries causes the hardest-to-debug production bugs.

HARD GATE — Contract files MUST be version-controlled alongside code. Outdated contracts are worse than no contracts. If a contract hasn't been reviewed in 30 days, flag it as stale.

Validate that data structures stay in sync across system boundaries — front-end vs back-end, API responses vs expected schemas, config files vs code assumptions, migration output vs target shape.

Contract types

Mode	What it catches	When to use
Schema	API response shape mismatches	Before every deploy, after API changes
Key-set	Missing/unexpected keys across two data sources	Translation files, configs, enum definitions
Shape	Column type or format violations	After migrations, before consuming exports

Contract file convention

All contract files live in specs/contracts/ as YAML. See REFERENCE.md for extended examples.

Key-set example

# specs/contracts/i18n-keys.yaml
sources:
  reference: src/locales/en.json
  target: src/messages/en.json
mode: subset

Process

1. Define contract

Create a YAML file in specs/contracts/ following the schema for the mode.

2. Run validation

bash scripts/validate-contracts.sh specs/contracts/<contract>.yaml

The runner auto-detects key-set contracts (sources: block). Schema and shape modes are documented in REFERENCE.md for consumer projects.

3. Read the report

PASS: key-set contract
# or
FAIL: key-set — N keys in reference missing from target

JSON Lines output for CI is planned for schema/shape modes; key-set failures exit non-zero.

4. Fix divergence

• Missing keys → add to target source
• Type mismatches → update schema or fix producer
• Shape violations → fix migration or consumer

5. Re-validate

bash scripts/validate-contracts.sh specs/contracts/<contract>.yaml

Verify arc

Part of ★ VERIFY ★: verify-work → validate-contracts → smoke-test → run-evals → audit-code

Verify

→ verify: test -x scripts/validate-contracts.sh && bash scripts/validate-contracts.sh --self-test && grep -q 'validate-contracts.sh' skills/validate-contracts/SKILL.md && echo OK