Whole-disk file search for macOS: names in about 0.1 ms, typo-tolerant, plus indexed search inside files. A CLI with a small daemon, a Rust crate, or an MCP server for coding agents.

cargo build --release && ./target/release/fsearch install   # -> ~/.local/bin/fsearch
fsearch fsearch main              # find files by name
fsearch 'ext:rs grep:apply_dir'   # search inside files

Or skip the Rust toolchain with a release build for Apple Silicon:

curl -L https://github.com/noahdunnagan/fsearch/releases/latest/download/fsearch-aarch64-apple-darwin.tar.gz | tar xz && ./fsearch install

M4 Mac mini, a home holding the Linux or the Chromium source tree, vs the previous version (b88f4e9). Medians; Linux / Chromium.

The index is a third smaller while holding a third more text: one 3-bit filter per file instead of two, compressed posting lists and paths, and bit-packed name arrays read in place. Grep's first page reads a few more files for it, and the deeper typo search costs a little on names.

fsearch 'readme in:~/Developer'          # inside a folder
fsearch 'type:image size:>5mb mtime:<7d'
fsearch 'ext:rs regex:fn\s+\w+_dir'      # regex inside files
fsearch 'sym:apply_dir'                  # where it's defined
fsearch 'src/**/*.{c,h} !test/ init'     # globs, in or out
fsearch 'git:modified in:~/Developer/app'

Words are fuzzy and forgive a typo at any letter, two in words of 8+ (mian.rs finds main.rs); several words can spell one name. Accented names match however they were stored. Also 'exact, ^prefix, suffix$ and !exclude. Filters: ext: type: kind: in: size: mtime: re: path: grep: regex: sym: limit: and git: (modified staged untracked clean tracked ignored conflict). Content search is smart-case, and regexes match within a line, as in ripgrep.

Text files up to 1 MB, and up to 10 MB inside git repos, minus what git ignores. It leaves out lockfiles, JSON of 100 KB and up, minified or bundled assets, linked git worktrees (their main checkout is indexed), and build-output folders outside repos. To leave out more, list folders in ~/Library/Application Support/FSearch/content-skip.txt, one per line (~ and # comments work). Names are always indexed, and a grep inside a file you name still reads it.

From a terminal with Full Disk Access it indexes everything. As a login item (fsearch install --login), grant ~/.local/bin/fsearch access in System Settings > Privacy & Security, again after each rebuild. Without access it skips protected folders instead of prompting.

JSON lines over ~/Library/Application Support/FSearch/fsearch.sock, or fsearch stdio:

{"q": "fsearch main", "limit": 20, "offset": 20}
{"op": "grep", "pattern": "apply_dir", "in": "~/Developer", "context": 2}
{"q": "main.rs", "boost": true, "near": "~/Developer/app/src/lib.rs", "git": true}
{"op": "open", "path": "~/Developer/app/src/main.rs"}
{"op": "recent", "in": "~/Developer/app"}

open tells it what you opened; "boost": true ranks those higher for a while, near favors files close to the one you're in, and recent lists what you worked on lately. "git": true adds each hit's git status.

For coding agents, fsearch mcp is an MCP server on stdio with find_files, grep and multi_grep.

Or link the crate:

let engine = fsearch::Engine::start(fsearch::Options { dir: fsearch::default_dir(&home), home: home.clone(), skip: None })?;
let hits = engine.search(&fsearch::Query::parse("fsearch main", &home)?)?;

An app and the CLI share one index: the first process owns it, the rest follow.

• Crawls the disk once with getattrlistbulk, then follows FSEvents: changes show up in about 15 ms, and a restart replays only what changed. On a first run, a search in a folder indexes that folder first.
• Names live in one mmap'd file, folder by folder, so in: is a range. A bitmap of each name's letters rules out most names before scoring.
• Content search is a trigram index plus a per-file filter, so a search only reads files likely to match. Identical files are indexed once, and deleted files' entries are compacted away. Matches are read fresh from disk; files edited since the last index sync are read directly.
• The daemon runs with malloc's space-efficient mode, so it gives memory back when idle.