LiteLLM Structured Output Fails for Anthropic Models on AWS Bedrock

What this error means

BedrockException - structured output (JSON schema) does not work correctly for Anthropic models on Bedrock/converse is a LiteLLM failure pattern reported for developers trying to fix structured output / json schema responses failing when using anthropic models via aws bedrock through litellm. Based on the imported evidence, treat this as a tool-specific troubleshooting page rather than a generic API error.

Why this happens

LiteLLM issue #27846 reports structured output (JSON schema) failing on Converse API for Anthropic models on Bedrock. Users get BedrockException instead of valid structured responses.

Common causes

• Developers using LiteLLM’s Responses API with Anthropic Claude models on AWS Bedrock expect structured JSON output but get BedrockException. This breaks production pipelines relying on typed responses.
• LiteLLM issue #27846 reports structured output (JSON schema) failing on Converse API for Anthropic models on Bedrock. Users get BedrockException instead of valid structured responses.

Quick fixes

1. Confirm the exact error signature matches BedrockException - structured output (JSON schema) does not work correctly for Anthropic models on Bedrock/converse.
2. Check the LiteLLM account, local tool state, and provider configuration involved in the failing workflow.
3. Compare the failing environment with a known working setup, then change one configuration value at a time.

Platform/tool-specific checks

• Verify the command, editor, extension, or API client that produced the error.
• Compare local settings with CI, deployment, or editor-level settings when the error appears in only one environment.
• Avoid deleting credentials, local model data, or project settings until the failing scope is clear.

Step-by-step troubleshooting

1. Capture the exact error message and the command, editor action, or request that triggered it.
2. Check whether the failure is account/auth, quota/rate, model/provider, local runtime, or deployment configuration.
3. Review the source evidence below and compare it with your environment.
4. Apply one change at a time and rerun the smallest failing action.
5. Keep the working fix documented for the team or deployment environment.

How to prevent it

• Keep provider/tool configuration documented.
• Record non-secret diagnostics such as tool version, provider name, model name, and command path.
• Add a lightweight check before CI or production workflows depend on the tool.

Sources checked

• https://github.com/BerriAI/litellm/issues/27846

Evidence note: LiteLLM issue #27846 reports structured output (JSON schema) failing on Converse API for Anthropic models on Bedrock. Users get BedrockException instead of valid structured responses.

Related errors

• AWS Bedrock Anthropic model invocation error
• LiteLLM Bedrock Converse API timeout

FAQ

What should I check first?

Start with the exact BedrockException - structured output (JSON schema) does not work correctly for Anthropic models on Bedrock/converse text and the smallest action that reproduces it.

Can I ignore this error?

No. Treat it as a failed LiteLLM workflow until the root cause is understood.

Is this guaranteed to have one fix?

No. The imported evidence supports the troubleshooting path above, but tool behavior can vary by account, plan, version, provider, and local configuration.

How do I know the fix worked?

Rerun the same command, editor action, or request. The fix is working when that action completes without BedrockException - structured output (JSON schema) does not work correctly for Anthropic models on Bedrock/converse.