Summary

Fixes spurious external_directory permission prompts when running opencode from a subdirectory within a git worktree (e.g., monorepo packages/some-package).

Closes #7758

Root cause: Path containment was checked only against Instance.directory (CWD), not Instance.worktree (git root). Paths within the worktree but outside CWD were incorrectly treated as external.

Related Issues

• [FEATURE]: Add cwd option to createOpencodeServer #3321 - Partially helps: running from subdirectory now allows access to worktree paths without permission prompts
• [FEATURE]:Display warning when agents.md is not accessible #3603 - Partially helps: AGENTS.md at worktree root can be read without permission prompts when running from subdirectory

Changes

• Add Instance.containsPath() method that checks both directory and worktree
• Guard against non-git projects where worktree === "/" to prevent allowing all paths
• Update assertExternalDirectory() helper to use Instance.containsPath()
• Update direct usages in file/index.ts and bash.ts
• Add comprehensive test coverage

Test Plan

bun test test/file/path-traversal.test.ts test/tool/external-directory.test.ts

Tests cover:

• Path inside directory
• Path inside worktree but outside directory (monorepo scenario)
• Path outside both directory and worktree
• Path with .. escaping worktree
• directory === worktree (repo root)
• Non-git project doesn't allow arbitrary paths

{
  "info": {
    "title": "fix external_directory permission in monorepos",
    "agent": "opencode",
    "models": ["claude-opus-4-5"]
  },
  "summary": [
    "user requested fix for issue #7758 and PR creation",
    "agent analyzed external_directory permission bug in monorepo subdirectories",
    "agent added Instance.containsPath() method checking both directory and worktree",
    "agent updated path checks in read.ts, edit.ts, patch.ts, bash.ts, file/index.ts",
    "agent added guard for non-git projects where worktree === '/'",
    "agent created comprehensive test coverage for path containment scenarios",
    "agent committed changes and opened PR #7811",
    "agent ran multi-agent code review with 3 parallel reviewers",
    "reviews confirmed fix addresses root cause correctly with no critical issues"
  ]
}