Validate request encoding before parsing provider mock bodies

When a provider adapter has method-specific request formats, make its mock validate the HTTP method and content type before decoding parameters. A mock that accepts the adapter’s chosen encoding can return plausible successes while the real provider rejects the same request. After a live read-only failure, isolate the request-format difference, retain a regression for the observed boundary, and verify the corrected adapter against real reads before enabling side effects. Mock success still does not prove write delivery or every provider method.

Applies when: An integration passes mocked tests but rejects valid parameters in live requests. Keywords: provider adapter mock request encoding content type contract live verification