GitHub App pdd-issue/sync can run on Gemini when Opus was intended

[Serhan-Asad]

Summary

A pdd-issue workflow for #1120 ran through the Gemini/Google path even though the intended model for the work was Opus. The run produced PR #1126, then launched a follow-up pdd sync job, but the sync had to be stopped manually once the wrong model path was noticed.

Evidence

• Source issue: Add /pdd budget control comments for GitHub App runs #1120
• PR created by the run: feat: PDD enhancement for #1120 #1126
• Change job: 2TDCfjwAWMaPZw0rqHy3
• Follow-up sync job: Sr7jY3XEyUpATiOACRkx
• Sync job log showed hardened Gemini CLI env setup for Sr7jY3XEyUpATiOACRkx.
• Hidden workflow state for the change run reported model_used: "google".
• User stop comment on Add /pdd budget control comments for GitHub App runs #1120: “This execution used the Gemini path, but the intended model for this work was Opus.”
• Firestore marked the sync job failed/stopped by user after that comment.
• PR feat: PDD enhancement for #1120 #1126 was closed after the stop.

Expected behavior

When a GitHub App-triggered PDD run is intended to use Opus, the full workflow should consistently use Opus, including any automatic follow-up pdd sync work. If the requested model cannot be honored, PDD should fail early before spending on a long run or creating a PR.

Actual behavior

The workflow ran on the Gemini/Google path and launched a follow-up sync on that path. This made the output untrusted and required manual termination.

Impact

• Wasted run time and cost.
• PR output cannot be trusted for review/merge.
• Automatic follow-up sync can continue on the wrong backend unless manually stopped.

Acceptance criteria

• GitHub App label/settings resolution preserves the intended model/provider for pdd-issue and follow-up sync jobs.
• Startup/progress comments clearly disclose the selected model/provider before meaningful work starts.
• If Opus is requested but unavailable or not selected, the run fails early with a clear issue comment.
• Tests cover model/provider resolution for pdd-issue plus pdd-opus, including automatic follow-up sync job creation.