merge-queue-readiness git:20260708.940bd06A

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---
name: merge-queue-readiness
description: Pre-queue merge-group CI simulation. Triggered before adding a PR to a GitHub merge queue. Prevents merge-queue kick-outs from integration test failures.
---

# Merge Queue Readiness

## Trigger
Before adding the PR to the merge queue (or before the final push if the repo uses a merge queue).

## Protocol
1. **Fetch latest main:** `git fetch origin main`
2. **Create a temporary simulation worktree (do NOT mutate the PR branch).** Use a project-relative path UNDER the swarm worktree base so the path is portable across OSes and its later removal is permitted by the worktree guardrail (paths outside `.swarm-worktrees/` are blocked). Do NOT hardcode `/tmp` — it does not exist on Windows.
   ```
   git worktree add .swarm-worktrees/merge-sim origin/main
   cd .swarm-worktrees/merge-sim
   git merge <pr-branch> --no-edit
   ```
3. **Run integration + unit tests against the merged result:**
   ```
   bun test tests/integration --timeout 120000
   bun test tests/unit --timeout 120000
   ```
   (Use per-file loops for hot modules per AGENTS.md invariant 6)
4. **If failures:** Fix on the PR branch, re-push, re-simulate. Always run the cleanup step (5) before re-simulating or on any exit path — do not leave the simulation worktree behind.
5. **Cleanup (run on EVERY exit path, including failure):** `git worktree remove --force .swarm-worktrees/merge-sim`. If the remove is guardrail-blocked or fails, delete the directory directly and run `git worktree prune`.
6. **Only after simulation passes,** add PR to the merge queue.

## Why this matters
PR-branch CI and merge-group CI test DIFFERENT things:
- PR-branch: tests the PR head commit in isolation
- Merge-group: tests a temporary merge of PR head + latest main

Integration tests that pass on the PR branch may fail in merge-group context due to test interactions exposed by the merged result.

## Root cause
A `swarm ci-simulate` command would automate this (issue #1746 item 5). This playbook is the manual protocol.