Dependencies
This page documents all dependencies, their versions, and why each is needed. Update this page when upgrading any crate.
Verified May 2026.
MSRV Policy
Minimum Supported Rust Version: 1.85 (Rust edition 2024).
The MSRV is set in Cargo.toml. It’s tested in CI on every commit. Don’t use language features or standard library APIs introduced after 1.85 without bumping the MSRV and updating this page.
Core Dependencies
| Crate | Version | Purpose |
|---|---|---|
| clap | 4.6 | CLI framework with derive macros and multicall support |
| tree-sitter | 0.25 | AST parsing for chunking, outline, snap, structural search |
| ast-grep-core | 0.42 | Structural pattern search (the --structural mode) |
| safetensors | 0.7 | Load embedding model weights (zero-copy mmap) |
| ndarray | 0.17 | Dense matrix operations for embedding inference |
| sprs | 0.11 | Sparse matrices for BM25 scoring (CSC format) |
| tokenizers | 0.23 | cl100k_base token counting for --budget enforcement |
| similar | 3.1 | Diff computation for prx diff |
| bloomfilter | 3.0 | Bloom filter for prx exists O(1) checks |
| serde | 1.0 | Serialization framework |
| serde_json | 1.0 | JSON output |
| xxhash-rust | 0.8 | Content hashing (xxh3 feature) |
| ignore | 0.4 | .gitignore-aware file walking (from ripgrep) |
| regex | 1.0 | Literal search and identifier extraction |
| thiserror | 2.0 | Typed library errors |
| anyhow | 1.0 | CLI error handling |
Optional Dependencies
These are only linked when the corresponding feature is enabled.
| Crate | Version | Feature | Purpose |
|---|---|---|---|
| rmcp | 1.x | mcp | MCP server (official Anthropic Rust SDK) |
| tokio | 1.x | mcp, watch | Async runtime (only linked for MCP and file watching) |
| notify | 9.0-rc | watch | File watching for prx index --watch |
The core binary without mcp or watch is fully synchronous. No async runtime is linked.
Dev Dependencies
| Crate | Version | Purpose |
|---|---|---|
| assert_cmd | 2.2 | CLI integration testing |
| predicates | 3.x | Assertion helpers for assert_cmd |
| tempfile | 3.x | Temp directories for tests |
| criterion | 0.8 | Benchmarking |
Tree-sitter Grammar Crates
All grammar crates must be compatible with tree-sitter 0.25.x. This version was chosen because it has the broadest grammar crate compatibility — only 1 of 15 grammar crates supports 0.26.x.
| Crate | Version | Language | Notes |
|---|---|---|---|
| tree-sitter-rust | 0.24 | Rust | LANGUAGE const |
| tree-sitter-python | 0.25 | Python | LANGUAGE const |
| tree-sitter-javascript | 0.25 | JavaScript | LANGUAGE const |
| tree-sitter-typescript | 0.23 | TypeScript, TSX | Two separate Language objects: LANGUAGE_TYPESCRIPT, LANGUAGE_TSX |
| tree-sitter-go | 0.25 | Go | LANGUAGE const |
| tree-sitter-java | 0.23 | Java | LANGUAGE const |
| tree-sitter-c | 0.24 | C | LANGUAGE const |
| tree-sitter-cpp | 0.23 | C++ | LANGUAGE const. Also compatible with 0.26. |
| tree-sitter-ruby | 0.23 | Ruby | LANGUAGE const |
| tree-sitter-bash | 0.25 | Bash | LANGUAGE const |
| tree-sitter-json | 0.24 | JSON | LANGUAGE const |
| tree-sitter-toml | 0.20 | TOML | language() function (not a const) |
| tree-sitter-yaml | 0.7 | YAML | Check source for access pattern |
| tree-sitter-html | 0.23 | HTML | LANGUAGE const |
| tree-sitter-css | 0.25 | CSS | LANGUAGE const |
Standard access pattern (14 crates):
#![allow(unused)]
fn main() {
use tree_sitter_rust::LANGUAGE;
let lang: tree_sitter::Language = LANGUAGE.into();
parser.set_language(&lang)?;
}TypeScript (special — two languages):
#![allow(unused)]
fn main() {
use tree_sitter_typescript::{LANGUAGE_TYPESCRIPT, LANGUAGE_TSX};
// Use LANGUAGE_TYPESCRIPT for .ts files
// Use LANGUAGE_TSX for .tsx files
}TOML (special — function, not const):
#![allow(unused)]
fn main() {
let lang = tree_sitter_toml::language();
parser.set_language(&lang)?;
}Why These Choices
clap over structopt: clap 4.x includes derive macros natively. structopt is deprecated.
tree-sitter 0.25 over 0.26: Grammar crate compatibility. Only 1 of 15 grammar crates supports 0.26.x.
safetensors over manual deserialization: Zero-copy mmap, standard format, maintained by HuggingFace.
ndarray over nalgebra: ndarray is the standard for numerical computing in Rust. nalgebra is better for linear algebra but ndarray’s array slicing is more natural for embedding operations.
sprs over manual sparse matrix: sprs is the standard Rust sparse matrix crate. CSC format is optimal for column-wise BM25 queries.
ignore over walkdir: ignore is from ripgrep and handles .gitignore correctly. walkdir doesn’t understand .gitignore.
similar over diff: similar is pure Rust and handles both line-level and character-level diffs. The diff crate is older and less maintained.
xxhash-rust over blake3: xxh3 is faster for content hashing where cryptographic security isn’t needed. blake3 is better for security-sensitive hashing.
thiserror + anyhow over custom error types: thiserror generates boilerplate for typed errors. anyhow is ergonomic for CLI error propagation. Using both is the standard Rust pattern.
Evaluating New Dependencies
Before adding a dependency:
- Check if an existing dependency already provides the functionality.
- Check the crate’s maintenance status (last commit, open issues, downloads).
- Check the MSRV — it must be <= 1.85.
- Check for security advisories via
cargo audit. - Check license compatibility (Apache 2.0 or MIT preferred).
- Add a comment in
Cargo.tomlexplaining why the crate is needed.
Run cargo deny check after adding any dependency. This checks for license compliance, duplicate dependencies, and security advisories.