[deep-report] Investigate Design Decision Gate merge-blocking failure/cost hotspot (cross-verified by 3 monitors) #52736

Description

Three independent monitoring agents converged on the same finding this cycle: the merge-blocking Design Decision Gate 🏗️ workflow is failing at a very high rate while still burning significant cost. audit-workflows (#52590) measured a 28.6% failure rate with real token usage but Turns=0 (a driver/engine crash signature, not a logic failure). copilot-session-insights (#52668) independently flagged a set of gate workflows including this one with 0/126 successes across 3 consecutive sampled days ("provenance-inversion" pattern). api-consumption (#52697) independently flagged the same workflow as a top-5 REST API consumer at 7,699 calls across only 9 runs. GitHub issue search shows 10+ historical [aw] Design Decision Gate failed auto-notifications (all individually closed), but no open issue tracks the underlying root cause.

Expected Impact

Identifying and fixing the root cause (likely a Copilot SDK/engine cold-start or driver crash, given the Turns=0 signature also seen elsewhere in the fleet) would restore a merge-blocking gate to reliable operation and cut wasted API/token spend on failed runs.

Suggested Agent

New Agent / audit-workflows follow-up — needs access to the workflow's run logs (agenticworkflows logs) filtered to this workflow, and a diff of recent changes to .github/workflows/design-decision-gate*.md or its shared components.

Estimated Effort

Medium (1-4 hours) — investigation plus a fix once root cause is identified.

Data Source

DeepReport Intelligence Briefing analysis run 2026-08-14, cross-referencing discussions #52590, #52668, #52697.

Generated by 🔬 Deep Report · agent · 279.4 AIC · ⌖ 53.2 AIC · ⊞ 11.4K · ◷

• expires on Aug 16, 2026, 7:14 AM UTC-08:00