pydantic-monty-runtime

The monty command-line binary for the Monty sandboxed Python interpreter.

Installing the wheel puts the compiled binary in the environment's scripts directory.

You normally don't install this directly — the pydantic-monty metapackage pulls it in alongside the Python bindings, which need it to spawn worker subprocesses. Install it on its own to get just the CLI, or to supply the binary to an existing pydantic-monty-client install:

bash

uv add pydantic-monty-runtime
# or
pip install pydantic-monty-runtime

Or to install the monty binary as a tool

bash

uv tool install pydantic-monty-runtime
monty --help

Usage

monty — start an interactive REPL
monty file.py — run a Python file
monty -c "<code>" — run a program passed as a string (like python -c)
-i / --interactive — run the file or -c program in a REPL session (like python -i)
-t / --type-check — type check (powered by ty) before executing
--type-check-format — diagnostic format: full (default), concise, json, github and the other ty formats (requires --type-check)
-m / --mount /host/path::/virtual/path[::mode[::write_limit_bytes]] — mount a host directory into the sandbox (ro, rw, or overlay)
--max-memory 10MB, --max-duration 0.5, --max-recursion-depth, --gc-interval, --max-suspensions — sandbox resource limits

Worker mode

monty subprocess runs the binary as a wire-protocol child: framed protobuf requests on stdin, framed events on stdout. This is how pydantic-monty runs sandboxed code with crash isolation, and is meant to be driven by a parent process, not by hand.

The wheels are built from the monty-runtime crate; see its readme for cargo features, telemetry, and the rest of the Rust-side detail.