| 1 | # Worktree Reference |
| 2 | |
| 3 | ### Worktree Awareness |
| 4 | |
| 5 | Squad and all spawned agents may be running inside a **git worktree** rather than the main checkout. All `.squad/` paths (charters, history, decisions, logs) MUST be resolved relative to a known **team root**, never assumed from CWD. |
| 6 | |
| 7 | **Two strategies for resolving the team root:** |
| 8 | |
| 9 | | Strategy | Team root | State scope | When to use | |
| 10 | |----------|-----------|-------------|-------------| |
| 11 | | **worktree-local** | Current worktree root | Branch-local — each worktree has its own `.squad/` state | Feature branches that need isolated decisions and history | |
| 12 | | **main-checkout** | Main working tree root | Shared — all worktrees read/write the main checkout's `.squad/` | Single source of truth for memories, decisions, and logs across all branches | |
| 13 | |
| 14 | **How the Coordinator resolves the team root (on every session start):** |
| 15 | |
| 16 | 0. **Check config.json overrides first** — read `.squad/config.json` in the current directory (or at the git root): |
| 17 | - If `teamRoot` is set → Team root = that path. **STOP — do not walk further.** |
| 18 | - If `stateLocation` is `"external"` → Resolve external AppData path. Team root = external path. **STOP.** |
| 19 | - Otherwise → continue to step 1. |
| 20 | 1. **Check CWD first** — does `.squad/` exist in the current working directory? |
| 21 | - **Yes** → Team root = CWD. This handles monorepos where `.squad/` lives in a subfolder. |
| 22 | 2. If not, run `git rev-parse --show-toplevel` to get the current worktree root. |
| 23 | 3. Check if `.squad/` exists at that root (fall back to `.ai-team/` for repos that haven't migrated yet). |
| 24 | - **Yes** → use **worktree-local** strategy. Team root = current worktree root. |
| 25 | - **No** → use **main-checkout** strategy. Discover the main working tree: |
| 26 | ``` |
| 27 | git worktree list --porcelain |
| 28 | ``` |
| 29 | The first `worktree` line is the main working tree. Team root = that path. |
| 30 | 4. The user may override the strategy at any time (e.g., *"use main checkout for team state"* or *"keep team state in this worktree"*). |
| 31 | |
| 32 | **Passing the team root to agents:** |
| 33 | - The Coordinator includes `TEAM_ROOT: {resolved_path}` in every spawn prompt. |
| 34 | - Agents resolve ALL `.squad/` paths from the provided team root — charter, history, decisions inbox, logs. |
| 35 | - Agents never discover the team root themselves. They trust the value from the Coordinator. |
| 36 | |
| 37 | **Cross-worktree considerations (worktree-local strategy — recommended for concurrent work):** |
| 38 | - `.squad/` files are **branch-local**. Each worktree works independently — no locking, no shared-state races. |
| 39 | - When branches merge into main, `.squad/` state merges with them. The **append-only** pattern ensures both sides only added content, making merges clean. |
| 40 | - A `merge=union` driver in `.gitattributes` (see Init Mode) auto-resolves append-only files by keeping all lines from both sides — no manual conflict resolution needed. |
| 41 | - The Scribe commits `.squad/` changes to the worktree's branch. State flows to other branches through normal git merge / PR workflow. |
| 42 | |
| 43 | **Cross-worktree considerations (main-checkout strategy):** |
| 44 | - All worktrees share the same `.squad/` state on disk via the main checkout — changes are immediately visible without merging. |
| 45 | - **Not safe for concurrent sessions.** If two worktrees run sessions simultaneously, Scribe merge-and-commit steps will race on `decisions.md` and git index. Use only when a single session is active at a time. |
| 46 | - Best suited for solo use when you want a single source of truth without waiting for branch merges. |
| 47 | |
| 48 | ### Worktree Lifecycle Management |
| 49 | |
| 50 | When worktree mode is enabled, the coordinator creates dedicated worktrees for issue-based work. This gives each issue its own isolated branch checkout without disrupting the main repo. |
| 51 | |
| 52 | **Worktree mode activation:** |
| 53 | - Explicit: `worktrees: true` in project config (squad.config.ts or package.json `squad` section) |
| 54 | - Environment: `SQUAD_WORKTREES=1` set in environment variables |
| 55 | - Default: `false` (backward compatibility — agents work in the main repo) |
| 56 | |
| 57 | **Creating worktrees:** |
| 58 | - One worktree per issue number |
| 59 | - Multiple agents on the same issue share a worktree |
| 60 | - Path convention: `{repo-parent}/{repo-name}-{issue-number}` |
| 61 | - Example: Working on issue #42 in `C:\src\squad` → worktree at `C:\src\squad-42` |
| 62 | - Branch: `squad/{issue-number}-{kebab-case-slug}` (created from base branch, typically `main`) |
| 63 | |
| 64 | **Dependency management:** |
| 65 | - After creating a worktree, link `node_modules` from the main repo to avoid reinstalling |
| 66 | - Windows: `cmd /c "mklink /J {worktree}\node_modules {main-repo}\node_modules"` |
| 67 | - Unix: `ln -s {main-repo}/node_modules {worktree}/node_modules` |
| 68 | - If linking fails (permissions, cross-device), fall back to `npm install` in the worktree |
| 69 | |
| 70 | **Reusing worktrees:** |
| 71 | - Before creating a new worktree, check if one exists for the same issue |
| 72 | - `git worktree list` shows all active worktrees |
| 73 | - If found, reuse it (cd to the path, verify branch is correct, `git pull` to sync) |
| 74 | - Multiple agents can work in the same worktree concurrently if they modify different files |
| 75 | |
| 76 | **Cleanup:** |
| 77 | - After a PR is merged, the worktree should be removed |
| 78 | - `git worktree remove {path}` + `git branch -d {branch}` |
| 79 | - Ralph heartbeat can trigger cleanup checks for merged branches |
| 80 | |
| 81 | ### Pre-Spawn: Worktree Setup |
| 82 | |
| 83 | When spawning an agent for issue-based work (user request references an issue number, or agent is working on a GitHub issue): |
| 84 | |
| 85 | **1. Check worktree mode:** |
| 86 | - Is `SQUAD_WORKTREES=1` set in the environment? |
| 87 | - Or does the project config have `worktrees: true`? |
| 88 | - If neither: skip worktree setup → agent works in the main repo (existing behavior) |
| 89 | |
| 90 | **2. If worktrees enabled:** |
| 91 | |
| 92 | a. **Determine the worktree path:** |
| 93 | - Parse issue number from context (e.g., `#42`, `issue 42`, GitHub issue assignment) |
| 94 | - Calculate path: `{repo-parent}/{repo-name}-{issue-number}` |
| 95 | - Example: Main repo at `C:\src\squad`, issue #42 → `C:\src\squad-42` |
| 96 | |
| 97 | b. **Check if worktree already exists:** |
| 98 | - Run `git worktree list` to see all active worktrees |
| 99 | - If the worktree path already exists → **reuse it**: |
| 100 | - Verify the branch is correct (should be `squad/{issue-number}-*`) |
| 101 | - `cd` to the worktree path |
| 102 | - `git pull` to sync latest changes |
| 103 | - Skip to step (e) |
| 104 | |
| 105 | c. **Create the worktree:** |
| 106 | - Determine branch name: `squad/{issue-number}-{kebab-case-slug}` (derive slug from issue title if available) |
| 107 | - Determine base branch (typically `main`, check default branch if needed) |
| 108 | - Run: `git worktree add {path} -b {branch} {baseBranch}` |
| 109 | - Example: `git worktree add C:\src\squad-42 -b squad/42-fix-login main` |
| 110 | |
| 111 | d. **Set up dependencies:** |
| 112 | - Link `node_modules` from main repo to avoid reinstalling: |
| 113 | - Windows: `cmd /c "mklink /J {worktree}\node_modules {main-repo}\node_modules"` |
| 114 | - Unix: `ln -s {main-repo}/node_modules {worktree}/node_modules` |
| 115 | - If linking fails (error), fall back: `cd {worktree} && npm install` |
| 116 | - Verify the worktree is ready: check build tools are accessible |
| 117 | |
| 118 | e. **Include worktree context in spawn:** |
| 119 | - Set `WORKTREE_PATH` to the resolved worktree path |
| 120 | - Set `WORKTREE_MODE` to `true` |
| 121 | - Add worktree instructions to the spawn prompt (see template below) |
| 122 | |
| 123 | **3. If worktrees disabled:** |
| 124 | - Set `WORKTREE_PATH` to `"n/a"` |
| 125 | - Set `WORKTREE_MODE` to `false` |
| 126 | - Use existing `git checkout -b` flow (no changes to current behavior) |