At Gusto we have some big repositories. Many tools struggle with large codebases and Claude Code is no exception.

File suggestion, when you type @rea and it suggests @README.md, is one area where the number of files in a project has an outsize impact on a UI interaction. Filtering 110,000 files every time you type a character can make claude choppy and slow.

Anthropic has offered a worksround for this problem by providing the fileSuggestion setting to allow customization for big repositories.

The built-in file suggestion uses fast filesystem traversal, but large monorepos may benefit from project-specific indexing such as a pre-built file index or custom tooling.

I hacked my own solution for our giant repo with claude: file-suggestion.sh is a custom file-suggestion command which builds a cache from git ls-files, if available. It falls back to fd or find outside of a git repository. These results are filtered with ripgrep and fzf, allowing fast fuzzy searching.

As a surprise bonus, using a custom script seems to fix the choppiness and UI lag that plagues big repos. My guess is that the need to spawn a custom script forces the app to run the filtering async. In a repo like Gusto’s core product, this can lag input considerably to where your keypresses stop rendering. Deleting characters is even worse, slowing to a crawl as the search space expands.

Hey, claude code devs, if you’re reading:

Move the file suggestion filtering off the main
UI thread so suggestions are returned async,
following an approach similar to spawning a
process for a custom fileSuggestion command.

If you want to try my script, make sure you have ripgrep, fzf and optionally fd installed.

Grab the script below (or point your own claude at it and ask for a version that works for you). You can also view the latest version if I didn’t already break the link by the time you get here.

curl -o ~/.claude/file-suggestion.sh https://raw.githubusercontent.com/martinemde/dotfiles/36f670bda583065f634f1e83c4a195b9ac39c17b/home/dot_claude/executable_file-suggestion.sh
chmod +x ~/.claude/file-suggestion.sh

Then add the following to ~/.claude/settings.json (ensure the path matches and the file is executable).

  "fileSuggestion": {
    "type": "command",
    "command": "~/.claude/file-suggestion.sh"
  }

Restart Claude Code, then test out the search by typing an @ and the start of a file. Fuzzy matching should let you match any fuzzy path after the first slash.

On our biggest repo, this drops the search time to about 62ms compared to around 1000ms without the index (one full second per bounce). The script watches for the .git/index or .git/HEAD to be newer than the cache file and automatically refreshes the cache.

The cache is stored in the project’s .claude/ directory, so you’ll want to ignore the .claude/file-suggestions.cache in your global gitignore file.

In order to attain speed and retain fuzzy matching, it pre-filters based on the first directory segment using ripgrep to cut down on results. This allows you to type pac/payroll to find packs/products/payroll/... but if you type pks/payroll or papay it may not return any results. This is a trade-off for speed that I’d don’t love since I was expecting neovim level fuzzy find.

I may experiment with dropping the pre-filter and accepting the slower results just to get more reliable fuzziness. Please let me know if you find a better way around it.