chore(probe): draft-payload probe (throwaway, do not merge)

[kyle-sexton]

Throwaway Phase 0b probe for docs/topics/claude-review-lanes/PLAN.md: verifies the ready_for_review payload delivers draft=false. Will be closed unmerged and the branch deleted.

[claude]

Claude finished @kyle-sexton's task in 1m 27s —— View job

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PR Review

• Gather context
• Read changed file
• Review against CLAUDE.md / REVIEW.md guidelines
• Post findings

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Scope: Single added file — .github/workflows/probe-draft.yml

Verdict: No findings. The probe is clean and correctly follows every relevant security constraint.

CLAUDE.md security checklist

Rule	Status
pull_request only — no pull_request_target / workflow_run with secrets	✅
No untrusted checkout ahead of any action step	✅
permissions: {} — zero token grants	✅
No uses: steps → SHA-pinning requirement is N/A	✅
No secrets referenced or echoed	✅
display_report / show_full_output / ACTIONS_STEP_DEBUG not present	✅

Injection safety (REVIEW.md §trust-boundaries-and-injection)

The two context values are routed through env: vars rather than being interpolated directly inside the run block:

env:
  EVENT_ACTION: ${{ github.event.action }}
  PR_DRAFT:     ${{ github.event.pull_request.draft }}
steps:
  - run: |
      echo "action=${EVENT_ACTION}"
      echo "draft=${PR_DRAFT}"

This is the recommended pattern — ${{ }} expressions are expanded at YAML-parse time before the shell sees them, so routing through env vars is the correct injection-safe approach. Both values are also GitHub-owned (an action-name enum and a boolean), not user-controlled strings, so the risk is minimal in any case.

Other observations

• timeout-minutes: 5 is appropriate for a no-op echo job.
• ubuntu-24.04 is a concrete runner label, not ubuntu-latest. ✅
• The workflow's own header comment makes the throwaway intent clear, which is good hygiene even for a probe that's never merged.

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Summary: Nothing to block or nit. The probe is safe, minimal, and purpose-built correctly.

[claude]

Claude finished @kyle-sexton's task in 52s —— View job

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Security Review

• Gather context
• Read changed file
• Analyze for security issues
• Post findings

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No security issues found.

The added workflow (probe-draft.yml) is as minimal a surface as a GitHub Actions workflow can be:

• Safe trigger: Uses pull_request (not pull_request_target or workflow_run with secrets), so fork PRs run with a read-only token and no org secrets — consistent with the repo's security ground rules.
• Empty permissions block (permissions: {}): no GITHUB_TOKEN capability granted.
• No uses: references: zero supply-chain surface.
• No checkout step: no untrusted code ever enters the workspace.
• No secrets or credentials touched.
• Context values are not injection-prone: github.event.action is a server-controlled enum (opened, ready_for_review); github.event.pull_request.draft is a boolean. Both are stored in env vars and expanded as ${VAR} in the shell — the correct pattern even if the values were user-controlled, which they aren't.

Nothing to flag in this lane.

[kyle-sexton]

Probe complete: opened(draft)=true, ready_for_review=false — recorded in docs/topics/claude-review-lanes/PLAN.md Phase 0. Closing unmerged.