AGZ Rust MCP: Open source developer tool

AGZ Rust MCP

What it does

Bounded Cargo validation: check, build, clippy, test, doc and fmt (check mode) targets, with structured diagnostics.
Validation across a feature, target and toolchain matrix; test and regression comparison.
Verifies a crate name and exact version in the registry and fetches the documentation for that version.
Rust Analyzer navigation for symbols, references, definitions, implementations and hierarchies (advisory).
Returns a verified edit package for rename and refactor; it does not write to the source.
Produces compiler-guided repair candidates for a failing revision.

Limits

What it does not do

Knowing the limits up front avoids surprises.

It does not write to source files; applying rename and refactor results is up to you.
It is not an operating-system sandbox: build scripts, tests and proc macros can run with the permissions of the server account. Use a container or OS sandbox for stronger isolation.
Rust Analyzer and audit results are advisory; Cargo and rustc are the authority.
A successful check does not count as permission or evidence for a later request.
It is published as open source; there is no separate support commitment.

Details

In detail

Tools

The server offers 20 tools in four groups.

Group	Tools	What they do
Validation and evidence	check, profile, verify, audit, explain	Bounded Cargo validation; rebuild and runtime comparison; feature, target and toolchain matrix; bounded static source audit; explanation of macro expansion, unmet trait obligations and cfg activation.
Crate documentation and context	crate_lookup, docs, context, api	Verifies a crate name and exact version; exact-version Rust documentation; a task-focused, revision-bound context capsule; resolving an API signature or type-checking candidate code in an isolated copy.
Rust Analyzer navigation	symbol, references, definition, symbols, implementations, hierarchy	Code navigation; results are advisory.
Edits and workflow that do not write to source	rename, refactor, change, repair, work	Verified edit package (not applied); a revision-bound changeset in the server's scratch area; compiler-guided repair candidates; running a work item with explicit gates and single-use handoffs.

Installation

Install from crates.io:

Terminal

rustup toolchain install 1.88.0
cargo install agz-rust-mcp --locked
agz-rust-mcp --version

To build from source, clone the repository from GitHub; the folder is named rust-mcp:

Terminal

cd rust-mcp
cargo +1.88.0 build --release -p agz-rust-mcp --locked
./target/release/agz-rust-mcp --version

Prebuilt archives are available for Linux x86_64, macOS arm64 and Windows x86_64, and Linux x86_64 also has an install script. On other platforms, use an archive, cargo install or a source build.

Connecting a client

The repository has configuration examples for ZCode, OpenCode, OpenCode2 and Codex. The client starts the server as a local process. OpenCode example:

opencode.json

{
  "$schema": "https://opencode.ai/config.json",
  "mcp": {
    "rust": {
      "type": "local",
      "command": ["agz-rust-mcp"],
      "enabled": true,
      "timeout": 120000
    }
  }
}

Configuration

Settings are read in this order of precedence: command line, AGZ_RUST_MCP_* environment variables (section separator __, for example AGZ_RUST_MCP_GATE__HARD_TIMEOUT_MS=600000), a TOML file passed with --config, and defaults. Main keys: server.allow_roots, server.allow_dependency_roots, gate.scope (workspace, shadow, affected), gate.cache (auto, project, isolated), rust_analyzer.workspace_code and docs.fallback.

Processes are controlled with a process group on Unix and a Job Object on Windows, and are stopped on timeout. Default limits: gate.hard_timeout_ms 600000, repair.wall_time_ms 120000, work.wall_time_ms 600000; results are at most 49152 bytes.

Trust limits

Cargo and rustc are the authority; Rust Analyzer and audit results are advisory.
On a path escape or an unverifiable symlink the operation fails closed; client roots can narrow access but cannot widen it.
rust_analyzer.workspace_code defaults to deny.

Skill packs

The repository includes four skill packs that work offline: agz-rust-workflow, agz-rust-repair, agz-rust-refactor and agz-rust-performance.

Contribute

How to contribute

Open an issue

Write the problem in the Issues section of the relevant repository. The version, your operating system and the steps that reproduce the problem are enough.

AGZ Rust MCP issues

Report a vulnerability privately

Do not post security findings in public issues. The reporting route and scope are on the security page.

Security page