[DOCS] Missing Structured Outputs incompatibility notice in Citations guide

Documentation Type

Missing documentation (feature not documented)

Documentation Location

https://platform.claude.com/docs/en/build-with-claude/citations

Section/Topic

The Feature compatibility section of the Citations guide.

Current Documentation

Under the "Feature compatibility" header, the documentation currently states:

"Citations works in conjunction with other API features including prompt caching, token counting and batch processing."

What's Wrong or Missing?

The documentation is missing a critical warning regarding the strict incompatibility between Citations and Structured Outputs (output_format). While this limitation is clearly documented in the Structured Outputs guide (https://platform.claude.com/docs/en/build-with-claude/structured-outputs), a developer primarily referencing the Citations guide would be led to believe the feature is compatible with other standard API features. Attempting to use both results in a 400 error that is not mentioned here.

Suggested Improvement

Add a prominent "Warning" block within the "Feature compatibility" section of the Citations guide to mirror the warning found in the Structured Outputs documentation.

Suggested Text:

Warning: Citations and Structured Outputs are incompatible Citations cannot be used together with Structured Outputs. If you enable citations on any user-provided document (Document blocks or RequestSearchResultBlock) and also include the output_format parameter, the API will return a 400 error. This is because citations require interleaving citation blocks with text output, which is incompatible with the strict JSON schema constraints of structured outputs.

Impact

High - Prevents users from using a feature

Additional Context

• Link to related documentation: The incompatibility is correctly noted at https://platform.claude.com/docs/en/build-with-claude/structured-outputs#feature-compatibility but is completely absent from the feature-specific page for Citations at https://platform.claude.com/docs/en/build-with-claude/citations.
• Providing this information on both pages prevents developers from architecting RAG solutions that rely on both features simultaneously before discovering the runtime error.