LiteLLM Structured Output Fails for Anthropic Models on Bedrock Converse

What this error means

BedrockException - The model returned the following errors: output_config.format: Extra inputs are not permitted is a LiteLLM failure pattern reported for developers trying to fix structured output json schema errors when using anthropic models via litellm on aws bedrock converse api. Based on the imported evidence, treat this as a tool-specific troubleshooting page rather than a generic API error.

Why this happens

Open issue on BerriAI/litellm. Responses API structured output fails on Bedrock Converse for Anthropic models with ‘Extra inputs are not permitted’ error. Affects production AI pipelines using LiteLLM as gateway.

Common causes

• Structured output is critical for AI app development. When LiteLLM’s bedrock/converse integration fails with Anthropic models, developers lose JSON schema enforcement — a core feature for production AI pipelines.
• Open issue on BerriAI/litellm. Responses API structured output fails on Bedrock Converse for Anthropic models with ‘Extra inputs are not permitted’ error. Affects production AI pipelines using LiteLLM as gateway.

Quick fixes

1. Confirm the exact error signature matches BedrockException - The model returned the following errors: output_config.format: Extra inputs are not permitted.
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: Open issue on BerriAI/litellm. Responses API structured output fails on Bedrock Converse for Anthropic models with ‘Extra inputs are not permitted’ error. Affects production AI pipelines using LiteLLM as gateway.

Related errors

• LiteLLM bedrock structured output
• Anthropic bedrock converse JSON schema error
• LiteLLM output_config.format error

FAQ

What should I check first?

Start with the exact BedrockException - The model returned the following errors: output_config.format: Extra inputs are not permitted 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 - The model returned the following errors: output_config.format: Extra inputs are not permitted.