PRODUCTION SCENARIO
A research tool sends document blocks with citations enabled and also sets output_config.format to a JSON schema so the answer parses cleanly. Every request now fails with a 400 error.
What explains the failure?
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Show answer and explanation
Answer: Citations and structured outputs cannot be used in the same request
The citations page states that enabling citations on any user-provided document together with output_config.format returns a 400, because citations interleave citation blocks with text and that conflicts with strict JSON schema constraints. The developer must pick one feature per request.
Official Source: https://platform.claude.com/docs/en/build-with-claude/citations ↗