Bug

claude-opus-4.6 is listed in DEFAULT_MODEL_IDS in extensions/github-copilot/models-defaults.js (v2026.4.29), but GitHub Copilot's API has dropped the model from its supported list. Any request to github-copilot/claude-opus-4.6 returns:

{
  \"error\": {
    \"message\": \"The requested model is not supported.\",
    \"code\": \"model_not_supported\",
    \"param\": \"model\",
    \"type\": \"invalid_request_error\"
  }
}

OpenClaw's failure handling treats this 400 model_not_supported as a provider-level failure, marks the entire github-copilot profile in cooldown, and cascades the user's fallback chain through every other model — even though only opus-4.6 is the unsupported one.

Reproduction

$ openclaw --version
OpenClaw 2026.4.29 (a448042)

$ openclaw agent --agent main --model github-copilot/claude-opus-4.6 --message \"ping\"
EMBEDDED FALLBACK: Gateway agent failed; running embedded agent: ...

gateway.err.log:

[agent/embedded] embedded run failover decision: stage=assistant decision=fallback_model reason=format from=github-copilot/claude-opus-4.6 rawError=400 {\"error\":{\"message\":\"The requested model is not supported.\",\"code\":\"model_not_supported\",\"param\":\"model\",\"type\":\"invalid_request_error\"}}
[agent/embedded] auth profile failure state updated: profile=sha256:... provider=github-copilot reason=format window=cooldown

In my logs over a 7-day window:

• 34 model_not_supported rejections, all for claude-opus-4.6
• Each one triggered a provider-wide cooldown that cascaded to subsequent calls (haiku-4.5, sonnet-4.6, opus-4.7), which then logged No available auth profile for github-copilot (all in cooldown or unavailable) — making it look like every Copilot model was broken.

Root cause

extensions/github-copilot/models-defaults.js:

const DEFAULT_MODEL_IDS = [
    \"claude-haiku-4.5\",
    \"claude-opus-4.5\",
    \"claude-opus-4.6\",   // <-- no longer in Copilot's catalog
    \"claude-opus-4.7\",
    \"claude-sonnet-4\",
    \"claude-sonnet-4.6\",
    \"claude-sonnet-4.5\",
    ...
];

opus-4.6 was a valid Copilot Claude model when this list was authored but Copilot's offering rotates. The list is stale.

Two issues, really

1. Stale catalog defaults. claude-opus-4.6 (and possibly claude-opus-4.5, claude-sonnet-4, claude-sonnet-4.5 — would need to verify on a fresh Copilot account) should be removed or made conditional on a runtime catalog probe.

2. Disproportionate failure handling. A single model_not_supported response for one model should not cooldown the entire provider profile. model_not_supported is a per-model concern, not a per-profile one. Suggest classifying this rejection differently (model-level cooldown only) so the fallback chain can still try other models on the same provider.

Suggested fix

Short-term (catalog): Drop claude-opus-4.6 from DEFAULT_MODEL_IDS. Add a comment that this list is best-effort and intentionally conservative.

Better (catalog): Probe Copilot's /v1/models (or the equivalent) at agent init and dynamically populate the model list rather than hardcoding.

Failure handling: Special-case code: \"model_not_supported\" in the auth-state cooldown logic to mark just the model unavailable on this provider, not the whole provider profile. Pseudocode:

if (errorCode === \"model_not_supported\") {
    markModelUnsupportedForProvider(provider, modelId);
    // do NOT cooldown the provider profile
} else {
    standardProviderCooldown(...);
}

Severity

Combines with #75348 (eager_input_streaming) to make Copilot effectively unusable for Anthropic models on v2026.4.29 and silently bills paid providers in the fallback chain. A user reported ~$5/day OpenRouter costs traced to this chain reaction.