Ollama Launch Claude Fails with API Error 400 When CLAUDE_CODE_USE_BEDROCK Is Set

What this error means

API Error (model_name): 400 Bad Request — Bedrock rejects Ollama model name is a Ollama failure pattern reported for developers trying to fix ollama launch claude 400 error when claude_code_use_bedrock is enabled in settings. Based on the imported evidence, treat this as a tool-specific troubleshooting page rather than a generic API error.

Why this happens

Active GitHub issue on ollama/ollama (May 2026). ollama launch claude sets the model name to the pulled local model (e.g., gemma4) but does not override backend routing. When CLAUDE_CODE_USE_BEDROCK=1 is in Claude Code settings.json, requests route to AWS Bedrock which rejects the model name with ‘API Error (gemma4): 400’.

Common causes

• When developers run ollama launch claude to use a local Ollama model with Claude Code, but have CLAUDE_CODE_USE_BEDROCK=1 set in ~/.claude/settings.json, Claude Code routes requests to AWS Bedrock instead of Ollama. Bedrock rejects the local model name (e.g., ‘gemma4’) with a 400 error. This is a subtle configuration conflict that’s hard to diagnose without knowing both tools’ settings interactions.
• Active GitHub issue on ollama/ollama (May 2026). ollama launch claude sets the model name to the pulled local model (e.g., gemma4) but does not override backend routing. When CLAUDE_CODE_USE_BEDROCK=1 is in Claude Code settings.json, requests route to AWS Bedrock which rejects the model name with ‘API Error (gemma4): 400’.

Quick fixes

1. Confirm the exact error signature matches API Error (model_name): 400 Bad Request — Bedrock rejects Ollama model name.
2. Check the Ollama 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/ollama/ollama/issues/16097

Evidence note: Active GitHub issue on ollama/ollama (May 2026). ollama launch claude sets the model name to the pulled local model (e.g., gemma4) but does not override backend routing. When CLAUDE_CODE_USE_BEDROCK=1 is in Claude Code settings.json, requests route to AWS Bedrock which rejects the model name with ‘API Error (gemma4): 400’.

Related errors

• Claude Code model routing not respecting local provider
• AWS Bedrock model name not found error
• CLAUDE_CODE_USE_BEDROCK environment variable conflicts

FAQ

What should I check first?

Start with the exact API Error (model_name): 400 Bad Request — Bedrock rejects Ollama model name text and the smallest action that reproduces it.

Can I ignore this error?

No. Treat it as a failed Ollama 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 API Error (model_name): 400 Bad Request — Bedrock rejects Ollama model name.