Fix OpenClaw Invalid Beta Flag: Find the Rejected Header and Repair Its Route

For an OpenClaw 400 invalid beta flag error, first identify the rejected beta name and the endpoint that received it. If an explicit, optional anthropic-beta header is unsupported on your selected proxy, remove only that setting. If OpenClaw or the proxy generated the header for a feature you need, repair that feature's supported request path instead. Keep the intended model, authentication method, and provider while you establish the cause.

Two older fixes need particular care. Adding beta_features: [] is not a documented universal OpenClaw repair, and setting context1m: false is no longer a general answer. Current OpenClaw documentation says it omits the retired context-1m-2025-08-07 header and automatically uses the native window of listed Claude models with generally available 1M context. OpenClaw's Anthropic provider documentation explains that behavior.

The practical sequence is: capture the failing route and beta values, find where they were added, make one supported change, confirm the Gateway loaded it, and send one short message through the same failing session. Configuration validation alone cannot establish recovery.

Identify the beta rejection before changing configuration

The exact upstream error matters more than a blank reply or generic “API error” in chat. Anthropic documents a 400 invalid_request_error for an invalid beta name or a beta unavailable to your organization. That does not make every 400 a beta problem, or establish that every managed service uses the same error format. See the beta header reference.

An error body can contain this identifying message:

{
  "type": "error",
  "error": {
    "type": "invalid_request_error",
    "message": "invalid beta flag"
  }
}

Record these details for the request that actually failed:

Use local diagnostics on the Gateway host under its service user. Replace research with the affected agent's actual ID:

AGENT_ID=research
openclaw --version
openclaw config file
openclaw config validate
openclaw gateway status
openclaw models status --agent "$AGENT_ID"

In the original chat, use /model status to check the selected route and runtime. Then watch the relevant logs:

openclaw logs --follow

Stop log following with Ctrl+C when you have the error. Do not paste authorization headers, API keys, or private prompts into a support report. If the error does not name a beta, inspect the header names and nonsecret beta values in the affected provider configuration and any authorized proxy diagnostics. The generic message alone does not identify which value to delete.

If the response instead reports a rejected credential or missing authentication header, use the OpenClaw 401 troubleshooting guide. A beta-header edit does not renew a credential.

Find where the header was added

There are three places to investigate. Check them in the order indicated by your actual route:

1. An explicit OpenClaw provider header. Look for models.providers.<id>.headers["anthropic-beta"] in the active configuration. A custom provider may deliberately set several supported betas, so the presence of the key alone is not an error.
2. A feature added by the OpenClaw adapter. Direct Anthropic requests can acquire beta headers through supported features, even when no explicit header exists in the file. Check the selected model's parameters, agent overrides, and enabled session features against the installed version's provider documentation.
3. A relay or middleware rule. If your authored header is absent but a downstream request still contains it, examine the proxy's forwarding or injection configuration. Editing OpenClaw cannot remove a header a later process independently adds.

Current OpenClaw suppresses implicit Anthropic beta headers on non-direct anthropic-messages endpoints: providers other than canonical anthropic, or a custom Anthropic base URL outside the public api.anthropic.com endpoint. It still permits an explicit anthropic-beta header when a proxy needs a supported feature. This distinction is documented under custom provider request shaping. It is not proof that every installed binary or relay implements that behavior.

For example, if your custom provider ID is relay, inspect just its beta header:

HEADER_PATH='models.providers["relay"].headers["anthropic-beta"]'
openclaw config get "$HEADER_PATH"

Change relay to the configured provider ID. Keep the whole path quoted, especially in zsh, so the shell does not interpret its brackets. config get reads a redacted configuration snapshot; it does not inspect the actual outbound HTTP request. The config CLI reference explains those limits.

Anthropic accepts multiple beta values using a comma-separated header or repeated headers. Treat the values as a list: if one is rejected, preserve the others that are both supported and required. Also check the feature's exact name, model, endpoint, organization eligibility, and regional availability. A beta intended for another API operation should not be copied onto every Messages request. Anthropic's beta documentation is the starting point for these checks.

Apply the repair that matches the selected route

Custom proxy: remove only an unsupported optional override

If you have confirmed that the entire explicit header is unnecessary and unsupported on the proxy, back up the active file reported by openclaw config file. Then remove that one authored setting:

HEADER_PATH='models.providers["relay"].headers["anthropic-beta"]'
openclaw config unset "$HEADER_PATH"
openclaw config validate

This example assumes the provider is named relay and that the header exists in the active authored configuration. An absent path makes unset exit with status 1 without changing the file; it does not mean an automatic or proxy-injected header disappeared. Read the command output before continuing. Read-only or Nix-managed configurations must be changed through their configuration owner rather than repeatedly trying a refused write. These behaviors are defined in the config CLI documentation.

If the header contains both required and unsupported values, edit that single header value in the active file to remove only the identified optional value, then validate. Preserve the remaining provider entry, authentication configuration, model catalog, and unrelated headers. A small JSON example from a tutorial should never replace the whole configuration.

If the beta is required, confirm that the proxy supports both the beta and its associated request fields. Repair its documented mapping or ask the proxy owner to resolve the incompatibility. Removing a header while retaining a dependent body field can produce a different 400; removing the feature can silently change the behavior you wanted. Do not represent either outcome as a successful repair of the required feature.

Direct Anthropic: match the rejected flag to its feature

An anthropic-beta header is valid only for the specific documented feature and access conditions. Correct an invalid name or wrong operation first. For a supported beta denied to your organization, establish eligibility or intentionally disable that optional feature; changing the spelling cannot grant access. Anthropic's beta header reference distinguishes these conditions.

Current OpenClaw has feature-generated headers beyond long context. For example, its direct API-key fast mode sends fast-mode-2026-02-01 for supported models, and opt-in server-side compaction sends compact-2026-01-12 with a compaction edit. It also documents automatic request shaping for particular models. These are conditional behaviors, not a list of flags every request should include. Check the corresponding Anthropic provider feature section before changing a parameter.

If the rejection specifically names the fast-mode beta, and you deliberately want standard speed on anthropic/claude-opus-5, the documented optional-feature change is:

openclaw config set 'agents.defaults.models["anthropic/claude-opus-5"].params.fastMode' false
openclaw config validate

Use the affected model ref, and check whether an agent or session setting overrides the default. This example does not disable other beta features. If you need fast mode, resolve its supported route and access instead of treating standard speed as an equivalent result.

For 1M context, discard the old assumption that context1m: true necessarily sends a beta. Current OpenClaw automatically sizes listed GA models, treats that parameter as a no-op on those models, omits the retired context-1m-2025-08-07 header, and drops legacy anthropicBeta entries containing it. Unsupported older models retain their normal window. Native Claude CLI has its own context budget and access conditions. The 1M context section covers these separate cases.

Consequently, setting context1m: false cannot be assumed to fix today's beta rejection or reduce a GA model's native window. If the retired header is actually visible downstream, check the running binary and proxy injection against the documented behavior. A long-context eligibility 429 is a different error and needs its own access or request-size diagnosis.

Amazon Bedrock: preserve the AWS connection and correct its adapter

For AWS-operated Bedrock, use OpenClaw's dedicated amazon-bedrock provider with the AWS SDK credential chain, the intended region, and the appropriate model access. An Anthropic API key is not a replacement for that authentication path. The OpenClaw Bedrock guide documents setup and discovery.

Do not force every Bedrock model into an old Converse configuration. Current OpenClaw documentation includes modern Claude models using the Bedrock Messages API as well as older Converse examples. Check the actual model, endpoint, and supported adapter together.

Also distinguish AWS-operated Amazon Bedrock from Anthropic-operated Claude Platform on AWS. Anthropic's comparison lists the standard anthropic-beta header as unsupported on Bedrock, while Claude Platform on AWS supports it subject to feature restrictions. The AWS location alone does not determine the API contract. See Claude Platform on AWS's API comparison.

If a relay has copied a direct Anthropic header onto a Bedrock request, repair that mapping while keeping the selected AWS route. If the required feature is unavailable through that route, stop and decide whether losing the feature or changing the approved provider is acceptable. A provider switch is a separate deployment choice.

Claude on Vertex AI: verify the Claude integration, not a Gemini setting

Claude on Vertex AI uses Google Cloud authentication and a managed Claude request format. Anthropic's guide places the model in the request URL and uses anthropic_version: "vertex-2023-10-16" in the body. Feature and model availability depend on that integration. See Claude on Vertex AI.

OpenClaw's documented google-vertex provider is part of its Gemini integration. That documentation does not establish a drop-in Claude-on-Vertex configuration. Renaming a Claude provider to google-vertex, or swapping in a Gemini model, does not repair the original Claude feature request. OpenClaw's Google provider page identifies this scope.

For an existing Claude Vertex adapter or proxy, identify its owner and follow its documented Claude mapping. Verify the rejected feature's support on that route before removing it. Do not assume every Vertex beta is prohibited, or replace Google Cloud credentials with an Anthropic key.

If you discover that the connection itself uses the wrong provider or adapter, the OpenClaw model setup guide explains provider selection and custom endpoints. Preserve the original requirements when rebuilding the connection.

Verify loading and a completed request separately

Keep the intended provider and feature requirements while choosing a repair.

First run openclaw config validate. If it fails, repair the reported configuration problem before reloading. An open-ended parameter object can be schema-valid while containing a field the upstream provider rejects, so validation is only the first check. The config CLI reference explicitly separates validation from a Gateway probe.

Next, follow the successful write's reload or restart guidance. A message describing the expected reload behavior is not an acknowledgment that the running Gateway has applied it. If a restart is required, use:

openclaw gateway restart
openclaw gateway status
openclaw logs --follow

Check for a reload or startup failure, the intended service instance, and the same selected route. Use openclaw doctor diagnostically if the installed version, service, or configuration appears inconsistent, and read its findings before applying a repair. doctor --fix is not a universal beta-header remedy or proof of upstream acceptance. The Gateway troubleshooting guide provides the service checks.

Finally, send one short, ordinary message through the original agent and chat session. Confirm that it receives a completed reply from the intended route without the original beta rejection. A fallback reply from another provider does not establish that the repaired route works. If you need the beta feature itself, test that feature after the basic request succeeds; ordinary text success does not prove compaction or another optional feature works. Live requests can consume provider usage or incur charges.

These instructions are based on documented configuration and provider behavior. The command syntax and path examples were checked offline; we did not run a live OpenClaw recovery or a model request for this guide.

Stop making header changes if the same rejection persists after confirmed loading. Capture the exact beta values, provider/model/runtime, endpoint host, version, affected session, and the result of the one scoped change. Give the redacted record to the owner of the layer still adding or rejecting the header. If the error changes to auth, quota, model access, or a dependent body-field error, follow that new condition instead of continuing to strip beta headers.

FAQ

Does beta_features: [] fix every OpenClaw invalid beta flag error?

No. Current OpenClaw documents explicit provider headers and conditional adapter behavior; an empty beta_features array is not a universal documented override. Identify the actual injected header and selected route before changing configuration. The custom provider rules explain implicit suppression and explicit overrides.

Should I disable context1m when I see this error?

Only if the affected runtime and feature documentation establish that it is the relevant setting. For listed GA direct-API models, current OpenClaw treats context1m as a no-op and does not send the retired context beta. Disabling it is not a general repair. The 1M context documentation also distinguishes native CLI budgeting.

Why can the error remain after I remove anthropic-beta from the file?

The running Gateway may not have loaded the change, a different provider or session may be active, or an adapter or proxy may add the header elsewhere. Verify loading and the failing session, then inspect the responsible layer. Removing an absent authored key cannot remove a generated header.

Can I keep some beta features and remove one rejected flag?

Yes, when the selected route supports the remaining features. Anthropic accepts multiple beta values; preserve supported required values and their dependent request fields. If the rejected feature is essential, repair its supported route or access rather than claiming recovery after disabling it. The beta header reference defines the direct API conditions.

Is a healthy Gateway enough to confirm the fix?

No. Gateway health establishes a local service condition. Recovery requires a completed request through the same intended agent, session, provider, and runtime, plus a feature-specific check if the rejected beta was required.