Claude Code Merge Queue 🚦

The local, zero-cost merge queue for parallel Claude Code agents. Several agents land, build, and test at the same time — this serializes it so push races, redundant heavy builds, and shared-resource test flakiness can't happen.

⚡ Quickstart

npm install --save-dev claude-code-merge-queue   # or: pnpm add -D / yarn add -D / bun add -d
npx claude-code-merge-queue init

Contents

• ⚙️ Configuration
• 🆚 vs. GitHub's Merge Queue
• 🧰 What's in the box
• 🚨 The emergency hatch
• 🔍 Know the limits
• 📄 License

⚙️ Configuration

Everything lives in one file — see examples/claude-code-merge-queue.config.mjs for every field with comments. The short version:

export default {
  branchPrefix: "lane/",               // lane/1, lane/2, ...
  worktreeSuffix: "-lane-",            // ../your-repo-lane-1
  portBase: 3000,                      // lane n gets portBase + n
  integrationBranch: "main",           // where agents land — see below
  productionBranch: null,              // set this for a two-stage model — see below
  protectedBranches: [],               // extra branches beyond the two above; most repos need none
  regenerableFiles: [],                // files a build tool rewrites — never block a rebase on these
  symlinks: [".env", ".env.local", "node_modules"],
  buildOutputDirs: ["dist", "build", ".next"], // preview never copies these onto your checkout
  checkCommand: "npm run check",       // what actually gates a landing — see below
  checksRequired: true,                // false = deliberately run with none; see below
};

A malformed config (empty branch names, a negative port, productionBranch equal to integrationBranch, ...) fails loud with every problem listed, the moment any command loads it — not a mysterious failure three steps later.

🆚 vs. GitHub's Merge Queue

| | GitHub Merge Queue | Claude Code Merge Queue | |---|---|---| | Private repo | Enterprise Cloud only | Any plan, any repo | | Cost per landing | GitHub Actions minutes, every queue attempt | $0 — runs on your own machine | | Requires | A pull request | Nothing — direct rebase + push |

Same idea — serialize landings, test before merge, keep history clean — run locally instead of in someone else's billed cloud.

🧰 What's in the box

| Command | What it does | |---|---| | claude-code-merge-queue hook worktree-create | A Claude Code WorktreeCreate hook. Plugs Claude Code Merge Queue's numbered lanes into Claude's native worktree creation. | | claude-code-merge-queue build-lock -- <cmd> | Runs <cmd> — your build — serialized across every lane, machine-wide. | | claude-code-merge-queue land | Rebases and pushes your lane onto the integration branch through a FIFO queue, so two lanes are never mid-push at once. Agents run this themselves. | | claude-code-merge-queue sync | Fast-forwards your main checkout so a dev server actually sees what just landed — and re-installs dependencies if the lockfile changed. | | claude-code-merge-queue promote | Ships the integration branch to production. Human-only — never in an agent's instructions, never automated. | | claude-code-merge-queue preview | Instantly mirrors a lane's live working tree — uncommitted changes included — onto the main checkout, so you can look at it without a build. | | claude-code-merge-queue port | Prints a lane's dev-server port, derived from its own directory name. | | claude-code-merge-queue prune | Removes already-landed sibling lane worktrees on demand. |

A pre-push hook makes land non-optional: a direct git push straight to the integration branch is rejected, with the actual command to run instead, and the same hook runs checkCommand before allowing a landing through — no checkCommand configured means every push fails by default. There's a way out for every block (see 🚨 The emergency hatch), but it takes naming the specific branch, not a generic flag.

📝 What init writes

• claude-code-merge-queue.config.mjs — integrationBranch and checkCommand auto-detected.
• CLAUDE.md (or appends to yours) — tells Claude Code to land its own work once green, without being asked.
• .claude/settings.json — the WorktreeCreate hook wired in, without touching anything else already there.
• .husky/pre-push — created or appended to, if you already have Husky. If you don't, init tells you rather than silently writing to the untracked .git/hooks/pre-push.
• package.json scripts — land, sync, promote, preview, preview:restore, skipping any you've already defined yourself.
• claude-code-merge-queue-preflight.mjs — a self-contained safety net that runs before land/sync, so a stale branch fails with a real diagnosis instead of a bare command not found.

🚨 The emergency hatch

Every blocked push — the integration branch, productionBranch, anything in protectedBranches — has a real way through it. One env var, no prompts, no second factor to remember:

CLAUDE_CODE_MERGE_QUEUE_EMERGENCY_PUSH=1 git push origin HEAD:main

This is a convention, not a hard guarantee: it stops mistakes and stray pushes, not an adversarial agent that sets the var itself.

🔍 Know the limits

• No human reviews any of this before it lands. checkCommand passing is the only gate — a real test suite and echo ok look identical to this tool. Want a human on every change? This is missing that step on purpose.
• Locks are crash-safe by PID liveness, not a timeout. kill -9 anything mid-claim and the next process notices the PID is dead and reclaims it — no stale locks, no timeout to tune.
• One machine, not a fleet. The FIFO queue lives in local temp storage — two machines landing at once just get git's ordinary non-fast-forward rejection.
• Not a security boundary. Every guardrail here stops mistakes and convention drift, not an adversarial agent — shell access always means git push --no-verify or editing the config on purpose.
• A slow checkCommand is a real throughput ceiling. The FIFO lock holds for its entire duration — a 3–4 minute suite caps you well under 20 landings/hour.
• Rebase conflicts abort, they never guess. git rebase --abort on any conflict, working tree left clean — CLAUDE.md tells the agent to resolve it and re-run land.

📄 License

MIT. Fork it, rename it, argue with the config shape — that's the point.