content-type-header-overrides-media-type

Finds a fixed Content-Type header value that disagrees with a request or response content key.

Attribute	Value
Category	Operations
Maturity	Platinum
OpenAPI	Swagger 2.0; OpenAPI 3.0, 3.1, 3.2
Starter	Off
Lenient–Strict	Warning
Complete	Error

Intent

Two conflicting media-type declarations leave Specmatic and other tools needing to choose which one wins.

Flags

• A request Content-Type header parameter with one known value that differs from a request-body content key.
• A response Content-Type header with one known value that differs from a response content key.

The known value may come from a one-value enum, const, default, or example. Media-type comparison is exact.

Does not flag

Matching values, headers without a stable single value, or operations without corresponding content.

See it fail

parameters:
  - name: Content-Type
    in: header
    schema:
      type: string
      enum: [application/xml]
requestBody:
  content:
    application/json:
      schema:
        type: object

The header says XML while the content map says JSON.

Fix it

Prefer one source of truth and remove the header declaration:

requestBody:
  content:
    application/json:
      schema:
        type: object

Configure

profiles:
  default:
    rules:
      extends: [recommended]
      override:
        content-type-header-overrides-media-type: error

Nearby: content-type-header-declared, accept-response-content-type-conflict.