[BUG] @ file picker doesn't support navigating into subdirectories

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

When using @ to reference files in the prompt, the autocomplete only shows top-level files and folders. There is no way to drill into a folder to select a file inside it.

• Typing @docs/ manually after selecting the folder does not trigger autocomplete for files within that folder
• The autocomplete does not match nested filenames either — e.g. typing @report or @helper does not find files inside subdirectories
• The only workaround is typing the full path manually (e.g. @docs/report.pdf), which defeats the purpose of the picker

Environment

• OS: Linux (Ubuntu, kernel 6.17.0)
• Claude Code: CLI

What Should Happen?

• Selecting a folder in the @ autocomplete by tab or enter should drill into it and show its contents for further selection
• Ideally, the autocomplete should also fuzzy-match filenames across all directories, not just top-level entries

Error Messages/Logs

Steps to Reproduce

1. Open Claude Code CLI in a project directory that contains subdirectories with files (e.g. docs/report.pdf, src/utils/helper.py)
2. Type @ in the prompt
3. See folder hints (e.g. docs, src)
4. Select a folder (e.g. docs) from the autocomplete suggestions using one of the following:

• Enter: The folder is selected but only the folder itself is attached — no further file hints appear
• Tab: Same behavior as Enter — the folder is selected with no further navigation into its contents
• Type / after the folder name: The input becomes @/ — the folder name is lost and replaced with just a slash. No files inside the folder are shown

Claude Model

Opus

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.1.100 (Claude Code)

Platform

Anthropic API

Operating System

Ubuntu/Debian Linux

Terminal/Shell

Other

Additional Information

_No response_