[aw-failures] Fix Auto-Triage Issues: replace unsupported `gpt-4.1-mini` model pin with supported model

[github-actions]

The Auto-Triage Issues workflow has been failing on every scheduled run today (9+ failures since 03:50 UTC) because gpt-4.1-mini is not supported on the current Copilot subscription tier. The fix is a one-line frontmatter change that has been documented since the first failure but has not been applied.

Evidence

Run ID	Time (UTC)	Error
§24815619962	03:49	400 The requested model is not supported.
§24821911567	07:09	400 The requested model is not supported.
§24833344626	11:46	400 The requested model is not supported.
§24833728558	11:55	400 The requested model is not supported.
§24833763586	11:56	400 The requested model is not supported.
§24834113424	12:04	400 The requested model is not supported.
§24836089306	12:48	400 The requested model is not supported.

Driver log pattern (identical across all runs):

copilot-driver: isModelNotSupportedError=true
model not supported — not retrying (the requested model is unavailable for this subscription tier)

Zero turns executed; zero tokens consumed. This is a pure configuration failure, no inference cost, no retries.

Root Cause

The Auto-Triage Issues workflow frontmatter specifies model: gpt-4.1-mini, which is not available for the current Copilot subscription tier. The copilot-driver detects this as a non-retriable error and exits immediately.

Proposed Fix

Update the Auto-Triage Issues workflow frontmatter:

# Before
engine: copilot
model: gpt-4.1-mini

# After — option A: use supported model
engine: copilot
model: gpt-5-mini

# After — option B: remove pin and use engine default
engine: copilot

The system prompt in §24836089306 was 18,342 bytes — lightweight enough for gpt-5-mini without cost concern.

Success Criteria

• Auto-Triage Issues workflow completes without 400 The requested model is not supported
• Next scheduled run after the frontmatter change succeeds
• Tracked issue [aw] Auto-Triage Issues failed #27958 can be closed

References

• Tracking issue: [aw] Auto-Triage Issues failed #27958
• Parent group: [aw-failures] [aw] Failure Investigator (6h) - Issue Group #27730
• Latest failed run audit: §24836089306

Generated by [aw] Failure Investigator (6h) · ● 250K · ◷

• expires on Apr 30, 2026, 1:17 PM UTC