
Cargo
- 135 repo stars
- Updated July 21, 2026
- Dave-London/Pare
io.github.Dave-London/cargo is a MCP server that runs cargo build, test, and clippy and returns typed JSON for coding agents.
About
io.github.Dave-London/cargo is an MCP server that runs familiar Rust cargo workflows—build, test, and clippy—and returns the results as structured JSON for AI coding assistants. Developers shipping Rust CLIs, side-project APIs, or embedded tooling often bounce between long rustc output and the chat window; this integration lets Claude Code, Cursor, or Windsurf consume consistent fields for errors, test failures, and lint violations instead of guessing at terminal formatting. It is a phase-specific developer integration: install it when Rust is part of your stack and you want the agent inside the edit-compile-test loop. It does not manage crates.io publishing, cross-compilation matrices, or production deploys by itself; pair it with your existing Makefile or CI and optionally the Pare docker or git servers for broader automation. Best results assume a working Rust toolchain on the host and a project that already builds with cargo. Advanced users benefit most when clippy is part of their daily quality bar.
- Wraps cargo build, cargo test, and cargo clippy into typed JSON responses
- Reduces agent hallucination on rustc and clippy message formatting
- stdio MCP via @paretools/cargo npm package (v0.7.1)
- Fits Rust CLIs, agents, and performance-sensitive backend services
- Shares Pare repo patterns with build, docker, and git MCP servers
Cargo by the numbers
- Data as of Jul 24, 2026 (Skillselion catalog sync)
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| repo stars | ★ 135 |
|---|---|
| Package | @paretools/cargo |
| Transport | STDIO |
| Auth | None |
| Last updated | July 21, 2026 |
| Repository | Dave-London/Pare ↗ |
What it does
Expose Rust cargo build, test, and clippy results to your agent as structured JSON so you can fix compile and lint issues faster.
Who is it for?
Best when you're building Rust backends or CLIs and want cargo build, test, and clippy wired into MCP-enabled agents.
Skip if: JavaScript-only stacks with no Rust toolchain, or teams that prefer pure terminal cargo with no agent mediation.
What you get
Cargo results land as structured JSON so your agent can triage errors, suggest patches, and re-run build or test commands with fewer round trips.
- JSON summaries of cargo build success or failure
- Structured test and clippy output for agent-driven remediation
By the numbers
- Server version 0.7.1
- npm package @paretools/cargo with stdio MCP transport
- Documented operations: cargo build, test, and clippy
README.md
Pare
Reliable, structured CLI output for AI agents — no more parsing fragile terminal text.
Pare provides MCP servers that wrap common developer tools (git, npm, docker, test runners, etc.) and return clean, schema-validated JSON instead of raw terminal text. Agents get typed data they can act on directly, without brittle string parsing.
The Problem
Parsing CLI output is fragile. Raw terminal text includes ANSI escape codes, decorative headers, progress bars, locale-specific formatting, and platform differences that break agent workflows in subtle ways. An agent that works fine with git status on macOS may fail on Windows because the output format changed. A test runner's summary line might shift between versions, silently breaking a regex.
Pare eliminates this entire class of errors by returning schema-validated JSON with consistent field names, regardless of platform, tool version, or locale. As a bonus, structured output is significantly smaller — agents use fewer tokens per tool call:
| Tool Command | Raw Tokens | Pare Tokens | Reduction |
|---|---|---|---|
docker build (multi-stage, 11 steps) |
373 | 20 | 95% |
git log --stat (5 commits, verbose) |
4,992 | 382 | 92% |
npm install (487 packages, warnings) |
241 | 41 | 83% |
vitest run (28 tests, all pass) |
196 | 39 | 80% |
cargo build (2 errors, help text) |
436 | 138 | 68% |
pip install (9 packages, progress bars) |
288 | 101 | 65% |
cargo test (12 tests, 2 failures) |
351 | 190 | 46% |
npm audit (4 vulnerabilities) |
287 | 185 | 36% |
Token estimates use ~4 chars/token. The biggest savings appear on verbose commands (builds, installs, tests). For simpler tools like
eslintortsc, the main advantage is reliable structured data — agents can use typed JSON directly rather than parsing strings.
How It Works
Each Pare tool returns two outputs:
content— human-readable text, for MCP clients that display itstructuredContent— typed, schema-validated JSON, ready for agents to process
This uses MCP's structuredContent and outputSchema features to provide type-safe, validated data that agents can rely on without custom parsing.
Example: git status
Raw git output (~118 tokens):
On branch main
Your branch is ahead of 'origin/main' by 2 commits.
(use "git push" to publish your local commits)
Changes to be committed:
(use "git restore --staged <file>..." to unstage)
modified: src/index.ts
new file: src/utils.ts
Changes not staged for commit:
(use "git add <file>..." to update what will be committed)
(use "git restore <file>..." to discard changes in working directory)
modified: README.md
Untracked files:
(use "git add <file>..." to include in what will be committed)
temp.log
Pare structured output (~59 tokens):
{
"branch": "main",
"upstream": "origin/main",
"ahead": 2,
"staged": [
{ "file": "src/index.ts", "status": "modified" },
{ "file": "src/utils.ts", "status": "added" }
],
"modified": ["README.md"],
"deleted": [],
"untracked": ["temp.log"],
"conflicts": [],
"clean": false
}
50% fewer tokens. Zero information lost. Fully typed. Savings scale with output verbosity — test runners and build logs see 80–92% reduction.
Available Servers (28 packages, 240 tools)
Install only the servers relevant to your stack — most projects need just 2–4. The full catalog covers a wide range of ecosystems so Pare works wherever you do.
| Category | Servers | Tools | Wraps |
|---|---|---|---|
| Version Control | git, github | 55 | git, gh |
| Languages & Packages | npm, python, cargo, go, deno, bun, nix, dotnet, ruby, swift, jvm | 101 | npm, pip, cargo, go, deno, bun, nix, dotnet, gem, swift, gradle, maven |
| Build, Lint & Test | build, lint, test, cmake, bazel | 23 | tsc, esbuild, vite, webpack, eslint, prettier, biome, vitest, pytest, jest |
| Infrastructure | docker, k8s, infra, security, remote | 40 | docker, kubectl, helm, terraform, ansible, trivy, ssh |
| Utilities | search, http, make, process, db | 21 | ripgrep, fd, curl, make, just, psql, mysql, redis, mongosh |
Tool Schemas — detailed response examples and field descriptions for every tool. See also Tool Response Examples for quick JSON samples.
Quick Setup
# 1. Configure MCP servers (non-interactive)
npx @paretools/init --client claude-code --preset web
# 2. Add agent rules to your project
# (append to existing CLAUDE.md, or copy if new)
cat node_modules/@paretools/init/rules/CLAUDE.md >> CLAUDE.md
# 3. Restart your client session
# 4. Validate
npx @paretools/init doctor
Available presets: web, python, rust, go, jvm, dotnet, ruby, swift, mobile, devops, full
Setup Guides by Client
| Claude Code | Claude Desktop | Cursor |
| VS Code / Copilot | Windsurf | Cline / Roo Code |
| OpenAI Codex | Gemini CLI | Zed |
| Continue.dev |
Full Quickstart Guide — presets, ecosystem mapping, validation
Manual Configuration — config paths and formats for all clients
Agent Integration Guide — rule files, hooks, CLI-to-MCP mapping
Configuration
Tool Selection
By default, every Pare server registers all of its tools. If a server exposes tools you don't need — or you want to limit which tools are available to an agent — you can filter them with environment variables.
Per-server filter — restrict a single server's tools:
# Only register status and log in the git server
PARE_GIT_TOOLS=status,log npx @paretools/git
Universal filter — restrict tools across all servers:
# Only register these specific tools across any server
PARE_TOOLS=git:status,git:log,npm:install npx @paretools/git
Disable all tools — set the env var to an empty string:
PARE_GIT_TOOLS= npx @paretools/git # no tools registered
| Env Var | Scope | Format | Example |
|---|---|---|---|
PARE_TOOLS |
All servers | server:tool,... |
git:status,npm:install |
PARE_{SERVER}_TOOLS |
One server | tool,... |
status,log,diff |
Rules:
- No env var = all tools enabled (default)
PARE_TOOLS(universal) takes precedence over per-server vars- Server names use uppercase with hyphens replaced by underscores (e.g.,
PARE_MY_SERVER_TOOLS) - Whitespace around commas is ignored
Common patterns:
# Read-only git (no push, commit, add, checkout)
PARE_GIT_TOOLS=status,log,diff,branch,show
# Minimal npm
PARE_NPM_TOOLS=install,test,run
# Only specific tools across all servers
PARE_TOOLS=git:status,git:diff,npm:install,test:run
In JSON MCP config, set via the env key:
{
"mcpServers": {
"pare-git": {
"command": "npx",
"args": ["-y", "@paretools/git"],
"env": {
"PARE_GIT_TOOLS": "status,log,diff,show"
}
}
}
}
Troubleshooting
| Issue | Solution |
|---|---|
npx not found / ENOENT on Windows |
Use cmd /c npx wrapper (see your client's setup guide) |
| Slow first start | Run npx -y @paretools/git once to cache, or install globally: npm i -g @paretools/git |
| Node.js version error | Pare requires Node.js >= 20 |
| NVM/fnm PATH issues | Use absolute path to npx: e.g., ~/.nvm/versions/node/v22/bin/npx |
| MCP connection timeout | Set MCP_TIMEOUT=30000 for Claude Code, or increase initTimeout in client config |
| Too many tools filling context | Use tool selection env vars to limit tools, or only install the servers you need |
Contributing
Each server is a self-contained package. See CONTRIBUTING.md for the full guide.
License
Recommended MCP Servers
How it compares
Structured cargo MCP wrapper, not rust-analyzer UI and not a generic brainstorming skill.
FAQ
Who is io.github.Dave-London/cargo for?
Rust-focused developers and small teams using AI agents who need reliable, JSON-shaped feedback from cargo build, test, and clippy.
When should I use io.github.Dave-London/cargo?
Use it while implementing or refactoring Rust crates when compile errors, failing tests, or clippy warnings block progress and you want the agent to drive the fix loop.
How do I add io.github.Dave-London/cargo to my agent?
Install @paretools/cargo from npm, register the stdio MCP server in your client config, and verify rustup, cargo, and your project build on the same machine.