| Full Fuzzer Name | ConstAndNotSchemaFieldsFuzzer |
| Log Key | CANSF |
| Description | Violates OpenAPI 3.1 const constraints (by sending a different value of the same type) and OpenAPI 3.0/3.1 not schemas (by sending a value matching the forbidden not schema). |
| Enabled by default? | Yes (included in ci, crash, and full profiles) |
| Target field types | Fields declaring const or not schema constraints |
| Expected result when fuzzed field is required | 4XX |
| Expected result when fuzzed field is optional | 4XX |
| Expected result when fuzzed value is not matching field pattern | 4XX |
| Fuzzing logic | For const fields, mutates the constant value (number + 1, !boolean, or string + "_violatedConst"). For not schemas, resolves the forbidden schema and synthesizes a value matching its const, enum, default, example, minimum, or type. |
| Conditions when this fuzzer will be skipped | When a field does not declare a const or not schema constraint. |
| HTTP methods that will be skipped | None |
| Reporting | Reports error if the server accepts the violated constraint with 2XX or crashes with 5XX; reports success when rejected with 4XX. |