git-worktree

name	git-worktree
description	Internal helper for public workflows that need an isolated git worktree for parallel feature work or PR review; use only when delegated by `spec-work`, `spec-code-review`, or another public workflow.
user-invocable	false
allowed-tools	Bash(bash *worktree-manager.sh*)

Worktree Isolation

Detect whether the current checkout is already isolated, then create a worktree under .worktrees/<branch> only when creation is still needed. The bundled script adds branch-specific setup that git worktree add alone does not handle:

• Does not copy .env* files by default; --copy-env is an explicit opt-in for workflows that need local env files
• Trusts mise/direnv configs, with branch-aware safety rules so review branches do not auto-grant trust to untrusted .envrc content
• Adds .worktrees to .gitignore if not already ignored
• Does not modify the main repo checkout — from-branch is fetched, not checked out

Step 0: Detect existing isolation

Before creating anything, invoke the bundled script with detect --json through the same bash -c wrapper whose command text includes exec bash ...worktree-manager.sh:

bash -c 'if [ -n "${CLAUDE_SKILL_DIR:-}" ]; then exec bash "$CLAUDE_SKILL_DIR/scripts/worktree-manager.sh" "$@"; fi; exec bash "$(git rev-parse --show-toplevel)"/"skills/git-worktree/scripts/worktree-manager.sh" "$@"' _ detect --json

The output is the deterministic facts contract git-worktree-detect.v1:

{
  "schema_version": "git-worktree-detect.v1",
  "state": "ordinary-checkout | linked-worktree | submodule | unknown",
  "reason_code": "same-git-dir | linked-worktree | submodule-superproject | not-git-repo | git-query-failed | output-contract-failed",
  "worktree_root": "<absolute path or null>",
  "main_worktree_root": "<absolute path or null>",
  "git_dir": "<resolved absolute path or null>",
  "common_dir": "<resolved absolute path or null>",
  "branch": "<current branch or null>"
}

state=ordinary-checkout and state=submodule mean creation may proceed if the workflow still needs isolation. For state=submodule, the new worktree is created under the submodule's own working tree (<submodule-root>/.worktrees/<branch>), not the superproject. state=linked-worktree means the current checkout is already isolated; report worktree_root and branch, then work in place instead of creating another worktree. state=unknown or any non-zero detect exit means stop and report reason_code; do not fall back to raw git worktree add.

The script computes this by comparing resolved absolute --absolute-git-dir and resolved absolute --git-common-dir. Equal paths are an ordinary checkout. Different paths plus non-empty --show-superproject-working-tree are a submodule. Different paths plus empty superproject output are an existing linked worktree.

detect --json requires node on PATH to serialize the facts. When node is missing the command still prints a parseable state=unknown/reason_code=output-contract-failed object and exits non-zero, so a consumer always gets a structured reason_code rather than empty output.

Creating a worktree

Invoke the bundled script through a bash -c wrapper whose command text includes exec bash ...worktree-manager.sh. On Claude Code, ${CLAUDE_SKILL_DIR} resolves to the skill's own runtime directory across marketplace-cached installs and local plugin development. In source or non-Claude runtime contexts, use the repo-root fallback path so generated Codex assets can rewrite it to the installed skill directory. This shape intentionally matches the narrow allowed-tools pattern.

bash -c 'if [ -n "${CLAUDE_SKILL_DIR:-}" ]; then exec bash "$CLAUDE_SKILL_DIR/scripts/worktree-manager.sh" "$@"; fi; exec bash "$(git rev-parse --show-toplevel)"/"skills/git-worktree/scripts/worktree-manager.sh" "$@"' _ create [--copy-env] <branch-name> [from-branch]

Defaults:

• from-branch defaults to origin's default branch (or main if that cannot be resolved)
• The new branch is created at origin/<from-branch> (or the local ref if the remote is unavailable)
• .env* files are not copied unless --copy-env is passed

Examples:

bash -c 'if [ -n "${CLAUDE_SKILL_DIR:-}" ]; then exec bash "$CLAUDE_SKILL_DIR/scripts/worktree-manager.sh" "$@"; fi; exec bash "$(git rev-parse --show-toplevel)"/"skills/git-worktree/scripts/worktree-manager.sh" "$@"' _ create feat/login
bash -c 'if [ -n "${CLAUDE_SKILL_DIR:-}" ]; then exec bash "$CLAUDE_SKILL_DIR/scripts/worktree-manager.sh" "$@"; fi; exec bash "$(git rev-parse --show-toplevel)"/"skills/git-worktree/scripts/worktree-manager.sh" "$@"' _ create fix/email-validation develop
bash -c 'if [ -n "${CLAUDE_SKILL_DIR:-}" ]; then exec bash "$CLAUDE_SKILL_DIR/scripts/worktree-manager.sh" "$@"; fi; exec bash "$(git rev-parse --show-toplevel)"/"skills/git-worktree/scripts/worktree-manager.sh" "$@"' _ create --copy-env feat/local-env

After creation, switch to the worktree with cd .worktrees/<branch-name>.

The create command consumes the same detection function before creating .worktrees/<branch> or running git worktree add. It refuses linked-worktree, unknown, not-git-repo, git-query-failed, and output-contract-failed states so this helper cannot create nested or invisible worktrees by bypassing Step 0.

Env File Opt-In

Use --copy-env only when the workflow explicitly needs local environment files in the new worktree. The opt-in path copies .env* files except .env.example, .env.template, and .env.sample, prints only file names, backs up pre-existing destination files, and appends .env-copy.log with timestamp, source path, destination path, byte size, and an 8-character content fingerprint. The log does not include file contents and is added to the worktree git exclude file.

Even when env files were copied intentionally, downstream staging must still treat them as denied by default. A batch may stage an env file only when the task/implementation unit declares the exact env path in expected_side_effects and explicitly states that changing that env file is intended.

Other worktree operations

Use git directly — no wrapper is needed and none is provided:

git worktree list                          # list worktrees
git worktree remove .worktrees/<branch>    # remove a worktree
cd .worktrees/<branch>                     # switch to a worktree
cd "$(git rev-parse --show-toplevel)"      # return to main checkout

Do not manually copy .env* files as a default setup step. If an existing worktree needs env files, recreate it with --copy-env or copy files manually only after a human explicitly opts in and records the same file-name-only audit information.

Dev tool trust behavior

When mise or direnv configs are present, the script attempts to trust them so hooks and scripts do not block on interactive prompts. Trust is baseline-checked against a reference branch:

• Trusted base branches (main, develop, dev, trunk, staging, release/*): the new worktree's configs are compared against that branch; unchanged configs are auto-trusted. direnv allow is permitted.
• Other branches (feature branches, PR review branches): configs are compared against the default branch; direnv allow is skipped regardless, because .envrc can source files that direnv does not validate.

Modified configs are never auto-trusted. The script prints the manual trust command to run after review.

When to create a worktree

Create a worktree when:

• Reviewing a PR while keeping the main checkout free for other work
• Running multiple features in parallel without branch-switching overhead
• Keeping the default branch free of in-progress state

Do not create a worktree for single-task work that can happen on a branch in the main checkout, and never create one when Step 0 reports state=linked-worktree.

Integration

spec-work and spec-code-review offer this skill as an option. When the user selects "worktree" in those flows, run Step 0 first. If isolation already exists, proceed in place. Otherwise invoke create through the same ${CLAUDE_SKILL_DIR} branch plus source/runtime fallback shown above, using a meaningful branch name derived from the work description (e.g., feat/crowd-sniff, fix/email-validation). Avoid auto-generated names like worktree-jolly-beaming-raven that obscure the work.

Troubleshooting

"Worktree already exists": the path is already in use. Either switch to it (cd .worktrees/<branch>) or remove it (git worktree remove .worktrees/<branch>) before recreating.

"Cannot remove worktree: it is the current worktree": cd out of the worktree first, then git worktree remove.

Dev tool trust was skipped: the script prints the manual command. Review the config diff (git diff <base-ref> -- .envrc), then run the printed command from the worktree directory.