# Targeted JSON contract negative fixture composer

Build-time release reference. Runtime readiness, deployment, payment settlement and external indexing are not evaluated here. Prices are proposed; this file cannot authorize execution or payment.

Compose invalid payloads from a caller-supplied valid seed with one structural edit, an exact target assertion and the complete bounded failed-assertion set.

Release: 0.29.0. Built: 2026-10-06T15:38:00Z.

## Choose for
- generate targeted negative request payloads from a valid JSON seed and supported schema
- compose one-edit contract violations with checked constraint isolation

## Outside this profile
- Target rejection guarantees, expected HTTP status, fuzz attacks or a mutation-testing score
- A valid seed is missing or incompatible with the supported structural schema
- Arbitrary JSON Schema, formats, regexes, references, combinators, nested objects or nested arrays
- Executing target tests, fetching services, running supplied code or proving security

Proposed nominal USD 0.005 per successful call; payer fees excluded. No verified runtime availability.

- [Exact release contract](/reference/services/json-contract-negative-cases.json)
- [Input schema](/reference/schemas/json-contract-negative-cases.input.json)
- [Output schema](/reference/schemas/json-contract-negative-cases.output.json)
- [Fixed example](/reference/examples/json-contract-negative-cases.json)
- [Complete HTML reference](/discover/tools/json-contract-negative-cases)