# Monty (Pydantic)

> MIT in-process Rust Python sandbox — OSS Monty only

**Category:** AI Agents  
**Pricing:** open-source  
**URL:** https://github.com/pydantic/monty  
**GitHub:** https://github.com/pydantic/monty  
**Added:** 2026-10-01

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## The Hook

Monty is Pydantic’s open in-process Rust Python sandbox — run untrusted Python beside the agent without spinning a whole VM SaaS for every eval.

## What's Good

MIT (pydantic/monty). OSS Monty only: `pydantic-monty` / `@pydantic/monty` / crates. Full Monty commercial is a separate product and is not required for the OSS bar. In-process Rust-backed Python sandbox aimed at agent tool runs and eval harnesses.

## The Catch

★8499 in about 41 weeks (~207 a week): judge it on the sandbox shape, not the star count. Vs E2B / AIO Sandbox / CubeSandbox: those are hosted Firecracker seats, broader sandbox/browser/MCP runtimes, or self-hosted RustVMM/KVM density — Monty’s catch is in-process Rust Python sandbox from Pydantic, not a sandbox SaaS seat. Do not confuse OSS Monty packages with Full Monty commercial; pin the MIT crates/npm/PyPI names.

## Verdict

MIT in-process Python sandbox when agents need Pydantic Monty OSS — not E2B/AIO/CubeSandbox cloud or KVM seats; ignore the ★ spike.