Git worktree isolation for Claude Code: context injection and parent project access prevention.

When Claude Code runs inside a git worktree, it can accidentally read or modify files from the parent project directory. This plugin prevents that by:

1. Injecting context at session start to inform Claude which path is the worktree and which is off-limits.
2. Blocking file access to the parent project path via a PreToolUse hook.

Session starts
  │
  ▼
SessionStart: worktree-context.ts
  ├── Not a worktree → no-op
  └── Worktree detected → inject additionalContext
        "Use: /path/to/worktree  Do NOT access: /path/to/parent"
                                            │
                                            ▼
                              Claude Code tool call (Read/Edit/Grep/…)
                                            │
                                            ▼
                            PreToolUse: deny-parent-access.ts
                              ├── Path is safe → pass through
                              └── Path is under parent project → deny

The hook uses two strategies:

Note: The hook provides best-effort isolation. It is not a complete security boundary. Bash commands are not intercepted.

1. Start the interactive claude shell:

   claude

2. Within the shell, add the marketplace and install the plugin:

   /plugin marketplace add pleaseai/claude-code-plugins
   /plugin install worktree@pleaseai

Alternatively, install directly from the command line (with optional --scope: user | project | local):

claude plugin marketplace add pleaseai/claude-code-plugins --scope project
claude plugin install worktree@pleaseai --scope project

cd plugins/worktree
bun test

# SessionStart — worktree detected
echo '{"cwd":"/path/to/project/.claude/worktrees/my-branch"}' | bun run hooks/worktree-context.ts

# PreToolUse — path denied (parent project access)
echo '{
  "tool_name": "Read",
  "tool_input": {"file_path": "/path/to/project/src/secret.ts"},
  "cwd": "/path/to/project/.claude/worktrees/my-branch"
}' | bun run hooks/deny-parent-access.ts

# PreToolUse — path allowed (worktree path)
echo '{
  "tool_name": "Read",
  "tool_input": {"file_path": "/path/to/project/.claude/worktrees/my-branch/src/safe.ts"},
  "cwd": "/path/to/project/.claude/worktrees/my-branch"
}' | bun run hooks/deny-parent-access.ts

MIT