# Legwork [![PyPI](https://img.shields.io/pypi/v/legwork-mcp)](https://pypi.org/project/legwork-mcp/) [![CI](https://github.com/kumarganduri/legwork/actions/workflows/ci.yml/badge.svg)](https://github.com/kumarganduri/legwork/actions/workflows/ci.yml) [![License: MIT](https://img.shields.io/badge/license-MIT-blue)](LICENSE) **Your AI finds the open-source tool it needs on GitHub. Legwork installs it in a sandbox.** https://github.com/user-attachments/assets/9e9b80b5-99ff-4d21-b689-74655418f23d

A real run in Claude Desktop. The 25-second install is sped up; the malware repos' names are masked.

Add Legwork to Claude, Cursor, Codex, opencode or any [MCP](https://modelcontextprotocol.io) client once. When you ask for something your AI has no tool for, it searches GitHub, picks a repo, and asks you to approve installing it. Legwork then checks the code for hidden payloads, builds a working tool for it in a sandbox, tests it, and hands it over. In your home folder it can only read the folders you allow. ```sh claude mcp add legwork -- uvx legwork-mcp hub --allow-read ~/Downloads ``` Then just ask. Four to try first, all from the [public cache](cache/), so they need no API key: - *"Use Legwork to transcribe ~/Downloads/memo.m4a."* Any voice memo, mp3 or video, offline. Best in English and other widely spoken languages; its small built-in model is unreliable for languages like Telugu. - *"Use Legwork to remove the background from ~/Downloads/photo.jpg."* - *"Use Legwork to pull the tables out of ~/Downloads/report.pdf."* - *"Use Legwork to make a QR code for https://github.com/kumarganduri/legwork."* Saying "use Legwork" matters in Claude Desktop: without it, Claude may reach for its own cloud code sandbox, which can't see the files on your computer unless you attach them. Your AI finds the tool ([faster-whisper](https://github.com/SYSTRAN/faster-whisper), [rembg](https://github.com/danielgatis/rembg), [pdfplumber](https://github.com/jsvine/pdfplumber), [qrcode](https://github.com/lincolnloop/python-qrcode)), you approve the install, and about a minute later it does the job. Files a tool makes are copied to `~/Legwork/outputs/`. On macOS, the first time a tool reads Downloads, macOS asks whether `uvx` may access it; allow it once. If something doesn't work, `uvx legwork-mcp doctor` checks your setup. Or build one tool yourself: `uvx legwork-mcp owner/repo` (a model key for repos not in the cache). ## Why not just ask your AI to install it? - **Most repos have no MCP server to install.** Your AI would have to write one on the spot, untested, every time. Legwork writes it once, proves it works with a self-test, and caches it so the next person doesn't pay for it. - **Whatever your AI installs runs with full access to your machine:** your SSH keys, your files, your environment variables. That's how the two malware repos below would have got in. Legwork checks the code for obfuscated payloads first, and every tool it installs runs sandboxed: in your home folder it sees only the folders you grant. - **It works across your tools:** the same install works in Claude Code, Claude Desktop, Cursor, opencode, Codex CLI, Goose and OpenClaw. ## What it did on real repos On 2026-09-26 we ran Legwork against **the 10 most-starred AI repos created on GitHub in the previous week**, taken exactly as search ranked them, with nothing skipped for being hard: | Outcome | Repos | |---|---| | ✅ Built a working MCP server | **3** — an npm CLI, a Python library, a Go binary | | ↩️ Refused, with the right reason | **5** — two Android/macOS apps, a desktop app, a repo with no usage docs, a tool that needs its own API keys | | 🛑 Blocked before install (malware) | **2** | Two of those top-10 "AI tools", about 700 stars each and three days old at the time, carried the same byte-identical obfuscated dropper under different file names. Legwork's pre-install scan refused both in about a second. Nothing from them was installed or run. Stars are not a trust signal. The tripwire has to stay quiet on ordinary code too. Run over the 150 most-starred Python, JavaScript and TypeScript repos on GitHub (2026-10-01), it blocks one: lodash, for a vendored 2009 debugging script that really does run `eval(unescape(...))`. Full write-up, including what failed along the way and what we fixed: [docs/designs/legwork-trending-trial-2026-09-26.md](docs/designs/legwork-trending-trial-2026-09-26.md). **A second, larger run** on the next 22 new trending repos, with two models: **gpt-5 built 12 and refused 10 with reasons, with no crashes**; OpenRouter's free Nemotron built 4. That run also caught two false malware alarms and a gap where only published packages could be installed, both fixed. [Write-up](docs/designs/legwork-trending-trial-2-2026-09-27.md). ## Let your AI find its own tools (hub) `legwork hub` is one MCP server that gives your AI five tools: `find_tools`, `install_tool`, `install_status`, `list_installed_tools` and `use_tool`. ```sh claude mcp add legwork -- uvx legwork-mcp hub --allow-read ~/Downloads ``` For Claude Desktop (macOS), download [legwork.mcpb](https://github.com/kumarganduri/legwork/releases/latest/download/legwork.mcpb) and double-click it. Desktop installs it as an extension and lets you pick the folders tools may read (Downloads by default) and whether they may use the internet, under Settings → Extensions → Legwork → Configure. It runs the released `legwork-mcp` from PyPI, pinned to that release. Or, for Cursor or Claude Desktop without the extension, add this to the MCP config (for Claude Desktop, while the app is quit), with your own user name in the path: a folder that doesn't exist stops the hub from starting. ```json { "mcpServers": { "legwork": { "command": "uvx", "args": ["legwork-mcp", "hub", "--allow-read", "/Users/you/Downloads"] } } } ``` For [opencode](https://opencode.ai), add this to `~/.config/opencode/opencode.json`. opencode runs MCP tools without asking by default, so the `permission` line is what makes it ask you before an install: ```json { "$schema": "https://opencode.ai/config.json", "mcp": { "legwork": { "type": "local", "command": ["uvx", "legwork-mcp", "hub", "--allow-read", "~/Downloads"] } }, "permission": { "legwork_install_tool": "ask" } } ``` - **You approve every install:** your client shows the repo and the folders it asks for. - **The hub's flags are the ceiling.** An install can ask for the folders you allowed or less, never more, and no network unless you started the hub with `--allow-net`. Secret folders (`~/.ssh`, `~/.aws`, ...) are refused outright. - **Installed tools appear by name** (`pdfplumber__extract_tables`), and `use_tool` works in clients that don't refresh their tool list. Installs are remembered across restarts. - **Search results tell your AI what matters:** stars, license, how recently the repo was updated, whether it's in the Legwork cache, whether it already has an MCP server, and a warning on very new repos (the malware we caught was three days old). Descriptions are marked as untrusted text. **37 tools are in the [public cache](cache/) and install in about a minute with no API key**: speech-to-text, OCR, background removal, PDFs and Office files, video, YouTube transcripts, charts, DuckDB and CSV tools, maths and units, and linters and formatters. Each was built, reviewed by hand and tried with a real call before it was added, and pins the version of the package it wraps (its dependencies resolve at install). The cache a release reads is the one tagged with that release, so a change to the cache reaches you only with an upgrade. Others need a model key, and building takes 1–5 minutes. Put the key in `~/.legwork.env` ([three lines](#model-providers), `chmod 600`) and the hub reads it when it needs to build, so the key never goes in your MCP config, where it would sit in plain text. `legwork find "extract tables pdf"` runs the same search from your terminal. - **Tools that use the internet** (YouTube transcripts and downloads, web pages) need the hub started with `--allow-net`; without it they install, then can't connect. - **Files a tool makes** (a trimmed video, a chart, a QR code) are copied to `~/Legwork/outputs//`, and the reply says where; images also come back inline. Your granted folders stay read-only, so a tool can't write next to your files. The copies are never executable, and on macOS they get the same quarantine flag as downloads. `--outputs DIR` puts them elsewhere, `--outputs off` turns copying off. - **GitHub allows 10 searches a minute without a token**, and each `find_tools` uses 2 to 4. Cached tools still show up when GitHub says no. For 30 a minute, add `GITHUB_TOKEN=` to `~/.legwork.env`. ### Other MCP clients Legwork is a standard MCP server over stdio, so any client that runs local MCP servers can use it. What differs is whether the client asks you before it calls a tool. Legwork labels its tools (searching only reads; installing acts), and the clients marked "asks" use those labels. | Client | Tested | Add Legwork | Before an install | |---|---|---|---| | Claude Code | ✅ | `claude mcp add legwork -- uvx legwork-mcp hub --allow-read ~/Downloads` | asks | | Claude Desktop | ✅ | JSON above | asks | | Cursor | ✅ | JSON above | its default Auto-review mode lets an AI decide, and ran installs without asking in our test; to approve every install, set Settings → Agents → Approvals & Execution to Allowlist and leave `install_tool` off the list | | opencode | ✅ 1.18 | JSON above | asks only with the `permission` line above | | Codex CLI | ✅ 0.159 | `codex mcp add legwork -- uvx legwork-mcp hub --allow-read ~/Downloads` | asks | | Goose | ✅ 1.52 | `goose session --with-extension "uvx legwork-mcp hub --allow-read ~/Downloads"` | asks with `GOOSE_MODE=smart_approve`; the default mode doesn't | | OpenClaw | ✅ 2026.9 | `openclaw mcp add legwork --command uvx --arg legwork-mcp --arg hub --arg --allow-read --arg ~/Downloads` | its default full-permission mode doesn't ask | | Gemini CLI, Cline, Zed, Continue, ... | not yet | the same command in the client's MCP config | check the client's settings | In every client, the folders and network you start the hub with stay the ceiling, whether or not the client asks. **Faster starts:** `uvx` downloads Legwork on the first run, which can be slower than some clients wait (Codex allows 10 seconds; add `startup_timeout_sec = 60` under `[mcp_servers.legwork]` in `~/.codex/config.toml`). Or install it once with `uv tool install legwork-mcp` and use the full path that `which legwork` prints, plus `hub ...`, as the command (desktop apps don't see your shell's `PATH`); `uv tool upgrade legwork-mcp` updates it. ## Quick start You need **macOS or Linux** and [uv](https://docs.astral.sh/uv/). Tools in the [public cache](cache/) need nothing else. For any other repo you also need a model key for an OpenAI-compatible chat-completions endpoint (see [Model providers](#model-providers)). Legwork itself is free; the only cost is your own model usage, which is 1–3 calls per build.
Linux: install bubblewrap (and one step on Ubuntu 24.04+) The Linux sandbox is [bubblewrap](https://github.com/containers/bubblewrap): ```sh sudo apt install bubblewrap python3-venv # Debian/Ubuntu sudo dnf install bubblewrap # Fedora ``` Ubuntu 24.04 and later block the user namespaces bubblewrap needs, unless a program's AppArmor profile allows them. Allow them for `bwrap` only (this is what Ubuntu does for Chrome and Flatpak), rather than switching the restriction off system-wide: ```sh sudo tee /etc/apparmor.d/bwrap <<'EOF' abi , include profile bwrap /usr/bin/bwrap flags=(unconfined) { userns, include if exists } EOF sudo apparmor_parser -r /etc/apparmor.d/bwrap ``` If anything's missing, Legwork stops and prints these instructions.
**Tested on every commit:** macOS on Apple silicon and Intel; Ubuntu on x86-64 and ARM64; Fedora; Debian. **Windows:** not supported natively. WSL2 should behave like Ubuntu (install bubblewrap) but hasn't been tested. A repo in the [public cache](cache/) needs no model and no API key: ```sh uvx legwork-mcp jsvine/pdfplumber ``` It installs and tests the cached wrapper in about a minute, then prints the line to connect it: ``` Installed the cached MCP wrapper for jsvine/pdfplumber; it passed its self-test here. What it wraps: Extract text, tables, and low-level page objects from local PDFs using pdfplumber's Python API Connect it to Claude Code: claude mcp add pdfplumber -- ~/.local/bin/uvx legwork-mcp serve jsvine/pdfplumber ``` For any other repo, Legwork has a model write the wrapper (1–5 minutes, 1–3 model calls on your own key; see [Model providers](#model-providers)): ```sh export LEGWORK_LLM_ENDPOINT=https://api.openai.com/v1 export LEGWORK_LLM_API_KEY=... # your own key; never a CLI flag export LEGWORK_LLM_MODEL=gpt-5 uvx legwork-mcp owner/repo ``` It also prints an `mcpServers` block for Claude Desktop, Cursor and other clients. For Claude Desktop, add it to `claude_desktop_config.json` **while the app is quit**: the running app writes its settings back on exit and drops edits it didn't make. For a permanent `legwork` command: `uv tool install legwork-mcp`. **Upgrading:** `uvx` keeps using the version it first downloaded. To get fixes (and the cache that ships with them), use `uvx legwork-mcp@latest` once, or `uv cache clean legwork-mcp`. `legwork doctor` warns when a client is pinned to an old version. **The name:** the package is `legwork-mcp`. `pip install legwork` and `uvx legwork` install an unrelated astronomy package. ## Model providers Any OpenAI-compatible chat-completions endpoint works. Put three lines in `~/.legwork.env` and make it private with `chmod 600 ~/.legwork.env`; Legwork reads it whenever the variables aren't set in your environment (and refuses it if other users can read it): ```sh LEGWORK_LLM_ENDPOINT=https://api.openai.com/v1 LEGWORK_LLM_API_KEY=sk-... LEGWORK_LLM_MODEL=gpt-5 ``` | Provider | `LEGWORK_LLM_ENDPOINT` | `LEGWORK_LLM_MODEL` (tested) | Cost | |---|---|---|---| | OpenAI | `https://api.openai.com/v1` | `gpt-5` | Your API credits | | Anthropic | `https://api.anthropic.com/v1` | `claude-sonnet-5` | Your API credits | | OpenRouter | `https://openrouter.ai/api/v1` | `nvidia/nemotron-3-super-120b-a12b:free` | Free models, rate-limited | | Ollama (local) | `http://127.0.0.1:11434/v1` | `gpt-oss:20b` | Free; 14 GB download, ~16 GB RAM | `LEGWORK_LLM_API_KEY` is your key (for Ollama, any non-empty value). **Ollama:** start it with a larger context window, or it silently cuts Legwork's prompt to ~2,000 tokens and the model never sees the instructions: `OLLAMA_CONTEXT_LENGTH=32768 ollama serve`. Legwork prints this tip when it detects Ollama. **OpenRouter free models** come and go and are often busy (HTTP 429). If one keeps failing, pick another from [their list](https://openrouter.ai/models?max_price=0). **Measured 2026-09-27**, same four repos on each (reverify, golive-skill, AnyJev, phone-harness), counting wrappers built: | Model | Built | Notes | |---|---|---| | gpt-5 | 4 / 4 | all on the first attempt | | Nemotron 3 Super (OpenRouter, free) | 3 / 4 | | | gpt-oss:20b (Ollama, local) | 3 / 4 | slowest: 1–3 min per reply on an M5 | | Claude Sonnet 5 | 1 / 4 | the most cautious: refused three, citing third-party accounts, a paired iPhone, and "a research pipeline" | A refusal isn't a crash: Legwork reports the model's reason and stops without installing anything. ## How it works 0. **Cache.** If the repo is in the [public cache](cache/), Legwork uses that wrapper instead of steps 3–4. It still clones and scans the repo, scans the cached wrapper too, and installs and self-tests it locally; if the self-test fails, it writes a fresh wrapper. `--no-cache` skips the cache. 1. **Fetch.** Checks the repo is public and reachable, then shallow-clones it. 2. **Scan.** Statically scans every Python and JavaScript/TypeScript file for obfuscated payloads: XOR-decoded byte arrays, computed imports, javascript-obfuscator output, `eval` of decoded strings, code hidden off-screen behind whitespace. A hit stops everything before install. 3. **Read.** The README, plus setup docs it links to (`install.md`, `docs/getting-started.md`, …), capped at 50KB with install and usage sections kept first. 4. **Write.** Your model writes the install command and a Python MCP wrapper with a self-test, or refuses with a specific reason: no programmatic entrypoint, needs hardware, needs its own credentials, needs a toolchain the sandbox doesn't have, and so on. 5. **Install**, sandboxed, network on. 6. **Self-test**, sandboxed, network off. A failure goes back to the model and it tries again, up to 3 attempts and 30 minutes. Attempts share one download cache, so a retry doesn't re-download multi-GB dependencies like PyTorch. 7. **Serve.** `legwork serve owner/repo` runs the wrapper as an MCP server over stdio, sandboxed, network off. ## Permissions: locked down unless you say so A served tool **can't read your home folder and has no network** until you grant them. Grant exactly what a tool needs when you add it to your client: ```sh # Build it once (cached: no key needed), then let it read one folder (read-only): uvx legwork-mcp microsoft/markitdown claude mcp add markitdown -- uvx legwork-mcp serve microsoft/markitdown --allow-read ~/Downloads # A tool that fetches web pages: uvx legwork-mcp serve owner/repo --allow-net ``` `--allow-read` is repeatable and always read-only. Some folders can't be granted even on request: `/`, your whole home folder, and a list of known credential locations (`~/.ssh`, `~/.aws`, `~/.config`, `~/.gnupg`, macOS keychains and browser data, Linux keyrings and Firefox profiles, `~/.npmrc`, `~/.pgpass`, `~/.legwork.env`, shell history and startup files, AI clients' configs), and any folder that contains one of those (such as `~/Library`). It's a list, so it can miss a place your setup keeps secrets. **A granted folder is readable in full**, including any `.env` file or key inside it: grant `~/Downloads`, not your code folder. A tool with a folder *and* `--allow-net` could send what it reads to the internet, so grant both only to a tool that needs both. With `--allow-net`, the tool can reach services on this machine (`localhost`) but not local sockets such as your SSH agent or Docker. Outside your home folder, tools can read system locations such as `/usr`, `/opt`, `/etc`, `/tmp`, macOS's per-user temporary folder, `/Users/Shared` and external drives under `/Volumes`, because Python and the libraries they need live there. Don't keep secrets in those places. (On Linux, `/tmp` is a private empty one.) On macOS, the first time a tool reads a protected folder (Downloads, Documents, Desktop), macOS itself asks whether `uvx` may access it. That's the operating system's own privacy check, on top of Legwork's grant; allow it once. ## What "built" means The self-test calls the **simplest** documented command and checks the shape of its result. So "built" means the wrapper starts and its simplest tool works. It does not mean every tool works. In the trial: - golive-skill's wrapper exposes its read-only commands, not its deploy flow, which needs accounts. - AnyJev's decision tool needs a running vLLM server, which the self-test didn't have. The same model writes the wrapper and its self-test, so a wrapper that misread the README can pass its own wrong test. **Cached tools have one more check:** a known answer, a fixed input and the output a person expects from it, which must pass before an entry is added or changed ([#3](https://github.com/kumarganduri/legwork/issues/3)). Tools that must reach the network at run time need `--allow-net`; without it the network is off. ## Risks, stated plainly Legwork runs code you didn't write: the target repo's install steps and a wrapper an LLM wrote from a README a stranger wrote. What contains it: - **Install time is the biggest risk.** Package installs and `install.sh` scripts run with network on, because they have to. The sandbox limits them to their own working folder: no access to your home directory (SSH keys, cloud credentials, dotfiles; system locations such as `/tmp` stay readable), no writes outside the folder, and an environment with none of your variables (including your model key). A malicious package can still misbehave inside that folder and reach the network during install. Legwork records which hosts it reached (`legwork log owner/repo`); see [THREAT_MODEL.md](THREAT_MODEL.md#what-is-recorded) for what that record can miss. - **The scan covers the repo's source, not what installers download.** magpie, for example, installs with the vendor's `curl … | sh`. For downloaded code, the sandbox is the protection. - **Prompt injection is not mitigated.** A README can steer the model into writing a wrapper that does something other than what you asked for. The wrapper still runs sandboxed with network off, which bounds the damage; it doesn't prevent a wrong or misleading tool. - **Linux on architectures other than x86-64 and ARM64:** install code can reach "abstract" Unix sockets (such as an X11 display), because the seccomp filter that blocks Unix sockets during install only covers those two. The run phase has no network and isn't affected. - **macOS can't stop a process that detaches itself.** Each install and self-test is cleaned up when it finishes, but on macOS code that deliberately detaches (`setsid`) can keep running afterwards. It stays in the sandbox (no home folder, no writes outside its own folder) but keeps the install step's network access until you log out. Linux's sandbox stops these too. - **Keep your key file in your home folder** (`~/.legwork.env`, the default). Sandboxed code can't read your home folder, but it can read most places outside it. - **Installs on Linux can reach services on this machine** (`localhost` databases, dev servers): bubblewrap shares the host's network during install. macOS blocks them. Unix sockets are blocked on both. - **Not yet:** `legwork serve` used on its own passes along anything a tool prints by mistake, which can confuse a client (the hub filters it out). - **The scan is an obfuscation tripwire, not a malware scanner.** It catches the hiding patterns seen in real payloads so far, and a determined author can get past it. The sandbox is the protection. The sandbox is `sandbox-exec` on macOS and bubblewrap on Linux, with the same rules on both: the system read-only, your home directory hidden, writes only in the build's own folder, no local sockets (SSH agent, Docker, display servers), only the system services builds need, and network only during install. If the sandbox isn't available, Legwork refuses to run. It never falls back to running unsandboxed. [THREAT_MODEL.md](THREAT_MODEL.md) has the full table of what a tool can reach in each phase, a comparison with Docker and VMs, and every escape found so far with the test that keeps it fixed. ## Commands | Command | What it does | |---|---| | `legwork hub [--allow-read PATH] [--allow-net]` | One MCP server through which your AI finds, installs and uses tools, within the limits you set | | `legwork find "keywords"` | Search GitHub for tools that do something, with facts to choose by | | `legwork owner/repo` | Build a wrapper (also `legwork build`), from the cache when possible. Accepts `owner/repo` or a github.com URL. `--no-cache` always writes a fresh one | | `legwork serve owner/repo` | Run the built wrapper as an MCP server over stdio. Needs no model key. `--allow-read PATH`, `--allow-net` grant access (see Permissions) | | `legwork contribute owner/repo [--out DIR]` | Write the build as a public-cache entry, ready for a PR (below) | | `legwork doctor` | Check this machine is ready: sandbox, cache, key, search limit, client configs. Read-only; prints no keys. Paste it into bug reports | | `legwork show owner/repo` | What a built tool came from: the commit that was scanned, the wrapper's hash, the install command and every package it installed | | `legwork log owner/repo` | A tool's record, written by Legwork outside the sandbox: the hosts each install reached, and what the sandbox blocked while it ran (macOS) | | `legwork clean [owner/repo]` | Free disk space: remove old and failed builds, keep the ones you serve. `--dry-run`, `--all` | Builds live in `~/.legwork` (override with `LEGWORK_HOME`). A failed build saves its full error output to `attempts.log` in its build folder. Each build keeps its own environment, which is several GB for repos that use PyTorch: `legwork clean` removes old and failed builds and keeps the ones you serve (`--dry-run` to preview, `--all` to remove everything). ## Contributing a wrapper `legwork contribute owner/repo` writes `cache/__/` containing `wrapper.py` and `manifest.json`, and prints a PR description. Before writing anything, it: - blocks the entry if the wrapper copies 50+ words in a row from the source repo - re-runs the self-test in the sandbox - blocks the write if any output contains something shaped like an API key, including your own configured key A GPL, AGPL, missing or unrecognized source license is flagged in the manifest and the PR description, but not blocked. If the repo has commits newer than the build or the existing entry, you get a warning. Open the PR yourself; a bad entry is removed with a plain `git revert`. ## Status Early. What's next: - Better multi-tool verification than a single simplest-command self-test. ## Development See [CONTRIBUTING.md](CONTRIBUTING.md). Security reports: [SECURITY.md](SECURITY.md). ```sh uv sync uv run pytest # sandbox tests need macOS, or Linux with bubblewrap ``` `tests/fixtures/ai_data_extractor_payload.py` is a real malicious file with its payload destroyed (every encoded byte randomized, code shape kept), so the scanner is tested against a real technique. Tests only parse it with `ast`; see `tests/fixtures/README.md`. ## License MIT