The read tool's 'did you mean' feature suggests similarly named folders outside the project worktree, leaking directory information that should be gated by the external_directory permission.

Steps to reproduce:

1. Create a folder on the desktop (outside worktree)
2. Use the read tool with a slightly misspelled path pointing to that folder
3. The tool returns 'File not found' but suggests the actual folder name as a 'did you mean' alternative

Expected: The read tool should not access or list contents of directories outside the worktree.

Actual: Directory entries from outside the worktree are exposed.