Investigate Copilot small model-alias failure in smoke workflow

[Copilot]

The Smoke Copilot Small run fails in the Copilot execution step with model 'small' is unsupported or unrecognized by this AWF version, despite the workflow intentionally using a model alias. This change adds a focused investigation artifact to capture evidence, scope, and next validation paths.

• What was added

  • New troubleshooting doc: docs/troubleshooting/copilot-model-alias-failure-investigation.md
  • Anchors the analysis to the exact failing run/job/step URL.
  • Records the observed failure signature, runtime env evidence, and emitted model alias map context.

• Findings captured

  • engine.model is set to small in workflow source.
  • Runtime passes COPILOT_MODEL=small.
  • AWF config includes alias mapping for small ("small": ["mini"]), but execution still rejects small before successful run.

• Follow-up paths documented

  • Compare behavior across alias (small, mini) vs concrete model (gpt-5-mini) to isolate where alias resolution diverges.
  • Use results to decide between AWF-path upgrade vs smoke workflow model selection adjustment.

engine:
  id: copilot
  model: small

[ERROR] Error: model 'small' is unsupported or unrecognized by this AWF version. Did you mean 'gpt-4'?

[pelikhan]

@copilot investigate what code generates this error message

[Copilot]

@copilot investigate what code generates this error message

Tracked this down in commit 0b3f244.

The message is not generated by code in github/gh-aw itself. In this repo, we generate and run the AWF invocation (pkg/workflow/awf_helpers.go) and set COPILOT_MODEL (pkg/workflow/copilot_engine_execution.go). The exact error string (model 'small' is unsupported or unrecognized by this AWF version...) comes from the external awf runtime (gh-aw-firewall) during that invocation.

[pelikhan]

@copilot find the root cause in the gitilhub/gh-aw-firewall sources

[Copilot]

@copilot find the root cause in the gitilhub/gh-aw-firewall sources

Addressed in commit b3d769a. Root cause is in github/gh-aw-firewall: src/commands/validators/config-assembly.ts validates COPILOT_MODEL via validateCopilotModel() and exits before runtime alias resolution. src/copilot-model.ts only checks a hardcoded SUPPORTED_COPILOT_MODELS set (plus retired aliases), so small is rejected before AWF_MODEL_ALIASES is applied by api-proxy.

[pelikhan]

@copilot refactor models.json to work around this issue so that the execution path avoids the improper checks. Flatten/expand model names.

[Copilot]

@copilot refactor models.json to work around this issue so that the execution path avoids the improper checks. Flatten/expand model names.

Implemented in 0b3a04e.

models.json is now flattened/expanded for Copilot by adding explicit mini and small model entries (mirrored in both pkg/cli/data/models.json and actions/setup/js/models.json) mapped to the gpt-5-mini profile so this execution path no longer depends on late alias resolution.