Contract Testing Specification Builder

Create contract specifications for this service integration:

{{service_interaction}}

Consumer requirements: {{consumer_expectations}}

Define:
1. Request/response schemas with examples
2. Error response contracts (HTTP status, body format)
3. State transitions and provider state setup
4. Headers, authentication, and metadata requirements
5. Edge cases and alternative flows
6. Backward compatibility rules
7. Contract versioning strategy
8. Test scenarios for both provider and consumer sides

Provide Pact or Spring Cloud Contract specifications (JSON/GROOVY).