When using OpenClaw to access Claude models through MixRoute API, you may encounter the “invalid beta flag” error. This guide provides complete diagnosis and fix solutions.
Problem Overview
Error Symptoms
The “invalid beta flag” error may manifest in several ways, but the crucial evidence is always in the Gateway logs and the resolved provider route. Your OpenClaw assistant may return:- Blank responses: No content returned
- Generic upstream 400 errors: HTTP 400 status code
- Provider-specific validation messages: Detailed error information from the provider
Error Format
"beta_features": [].Diagnosis Methods
Quick Diagnosis Commands
Run the following command sequence to diagnose the problem:Error Classification
- By Route Type
- By Error Cause
Fix Solutions
Solution Selection Guide
Custom Proxy
Direct Anthropic
Amazon Bedrock
Google Vertex
Detailed Fix Steps
Solution 1: Custom Proxy or Relay Fix
Keep the proxy, but stop pretending it is native Anthropic unless it is. Use an explicit provider id, set the correct API shape, and remove unsupported beta headers.Custom Proxy Configuration Example
Custom Proxy Configuration Example
- Confirm the API shape supported by the proxy
- Remove unsupported
anthropic-betaheader - Verify model id matches provider configuration
Solution 2: Direct Anthropic Long-context Fix
If you intentionally need 1M context, use direct Anthropic and confirm your credential is eligible. If you only enabled it because an old guide told you to, remove it.Direct Anthropic Configuration Example
Direct Anthropic Configuration Example
- Confirm whether you really need 1M context
- Check if credentials support long-context beta
- Verify model eligibility
Solution 3: Amazon Bedrock Fix
Use the Bedrock provider, not a direct Anthropic provider with AWS credentials pasted into the wrong place.Bedrock Configuration Checklist
Bedrock Configuration Checklist
AWS_REGIONorAWS_DEFAULT_REGIONenvironment variables- AWS credential chain availability
- Model access permissions in the target region
- Discovery permissions:
bedrock:ListFoundationModels,bedrock:ListInferenceProfiles
Solution 4: Google Vertex or Gemini-style Routes Fix
Keep the Google-owned auth flow and model route separate from direct Anthropic assumptions.Vertex AI Fix Steps
Vertex AI Fix Steps
- Keep Google authentication flow
- Remove explicit beta header
- Verify active provider route:
- Confirm model id matches provider route
Solution 5: Configuration Damage or Old Install Fix
When the error appears after an update or hand edit, assume the config may be stale or partially clobbered.Configuration Diagnosis Commands
Configuration Diagnosis Commands
Quick Fix Steps
Custom Anthropic-compatible proxy
models.providers entry and remove any hard-coded beta header unless your proxy explicitly supports it:Direct Anthropic 1M context
Bedrock
Prevention
Best Practices
Plan your provider route
Use built-in providers
openclaw onboard and provider docs first. Built-in providers own their auth and model picker behavior. Custom models.providers entries are for overrides, local runtimes, and proxies, not a replacement for every supported provider.Validate before going live
Document the route owner
Stay updated
Verification Checklist
openclaw config validate to confirm configuration is validopenclaw gateway status to confirm Gateway is running normallymodels.providers.<id>.headers for unsupported beta headersopenclaw --version is the latest versionFAQ
Applied the fix but still see the error?
Applied the fix but still see the error?
anthropic/... will not affect a relay/... or amazon-bedrock/... route. Then run openclaw config validate and inspect models.providers.<id>.headers for explicit anthropic-beta.Error appeared after an OpenClaw update?
Error appeared after an OpenClaw update?
openclaw --version, run openclaw doctor, and compare your active provider entry with the current provider docs.Can I use some beta features but not others?
Can I use some beta features but not others?
params.context1m: true on supported Anthropic Opus/Sonnet models only when the credential is eligible. For proxy or managed routes, do not add beta headers unless that route’s docs explicitly support them.Why does my friend's setup work without these changes?
Why does my friend's setup work without these changes?
Is this a bug in OpenClaw or the SDK?
Is this a bug in OpenClaw or the SDK?
Will this issue be fixed in future versions?
Will this issue be fixed in future versions?
How do I know if I'm using a beta feature without realizing it?
How do I know if I'm using a beta feature without realizing it?
anthropic-beta, context1m, and provider-specific params under agents.defaults.models. Then inspect the resolved model route with openclaw models status. A beta feature only matters if it is attached to the route actually handling the request.