Structured Outputs on the Claude Developer Platform (API) (www.claude.com)

Anthropic’s Claude Developer Platform now offers "structured outputs" in public beta for Sonnet 4.5 and Opus 4.1 (Haiku 4.5 coming soon), letting developers force API responses to exactly match a provided JSON schema or tool definition. By validating outputs at the model layer, Claude guarantees that generated responses conform to your schema or tool spec, removing a common source of runtime failures — malformed JSON, missing fields, or incorrect types — that can break downstream integrations like image data extraction, agent orchestration, or external API calls. Technically, structured outputs work two ways: include a JSON schema in the API request to get a schema-conformant JSON response, or register tool specifications so Claude’s outputs automatically match tool input formats. The feature promises no hit to model performance while reducing retries, simplifying error handling, and lowering the need for custom failover logic. That reliability is particularly valuable for production agents and pipelines where a single formatting error can cascade into broader failures. Documentation with supported JSON schema types, examples, and best practices is available on the developer site; ecosystem partners such as OpenRouter highlight the feature’s importance for stable, agentic AI workflows.