[aw-failures] Design Decision Gate: increase max-turns for ADR generation path #27470

Problem Statement

The Design Decision Gate workflow fails with terminal_reason: max_turns whenever a PR triggers ADR generation (i.e., has ≥100 business-logic additions and the implementation label). The workflow's current max_turns=5 budget is structurally insufficient for the ADR write+push execution path.

Affected Workflows & Run IDs

• Workflow: Design Decision Gate (claude engine)
• Failed runs:
  • §24698134887 — PR Add configurable agentic engine driver script support #27453 copilot/configure-agentic-engine-driver
  • §24697778261 — PR Add experimental OpenCode engine support, smoke workflow, and reassign LLM gateway ports #27466 copilot/add-support-agentic-engine-opencode
• Comparator (success, no-ADR path): §24697555895

Root Cause

The "ADR required" execution path needs a minimum of 6 turns:

1. Read adr-prefetch-summary.json + design-gate-config.yml (parallel)
2. Read pr.json + pr.diff (parallel)
3. Check existing ADRs in docs/adr/
4. mkdir -p docs/adr
5. Write the ADR file locally
6. push_to_pull_request_branch + call safeoutputs

With max_turns=5, step 6 is never reached. In run §24698134887, the ADR was written locally at turn 5 but the push was never attempted. In run §24697778261, even the write was cut off mid-turn.

Both failures produced empty agent_output.json ({"items":[]}), causing the safe_outputs job to be skipped and the workflow to exit with code 1.

Proposed Remediation

Option A (Recommended — lowest risk): Increase max-turns from 5 to 7 in the Design Decision Gate workflow configuration. This gives a 2-turn buffer for the ADR path without affecting the no-ADR path (which uses only 4 turns).

Option B: Move mkdir -p docs/adr to a deterministic pre-agent shell step, freeing one turn in the agent budget.

Option C: Combine the Write + push_to_pull_request_branch into a single agent action using a shell script step, reducing the turn count needed.

Success Criteria

• Design Decision Gate succeeds (exit 0) on PRs with implementation label and ≥100 business-logic additions
• ADR file is committed to the PR branch
• safeoutputs is called with a non-empty result
• No regression on the no-ADR path (PRs below threshold continue to complete in ≤5 turns)

Related

• Parent investigation: [aw-failures] Failure Investigation Report — 2026-04-21 (6h window) #27469
• Stale predecessor (different root cause, now closed): [aw] Design Decision Gate 🏗️ failed #27405

Generated by [aw] Failure Investigator (6h) · ● 609K · ◷

• expires on Apr 28, 2026, 1:21 AM UTC