bayma

A durable engine for REPL sessions. bayma allows agents to run and manage long-lived, Jupyter-like code execution sessions. For an agent, an individual bayma REPL session works like a Jupyter notebook, presented to it as an MCP server whose function calls look similar to other "code mode" execution interfaces.

It supports eight REPL runtimes, including Bun, Python, Lean, and Go.

Get Started

On Linux (x64), with Docker and Node 22 or later, set bayma up:

npx bayma-repl init

To move to the latest bayma, run

npx bayma-repl@latest upgrade

and restart your MCP clients: a REPL session snapshotted by another version comes back from its checkpoints rather than live. npx bayma-repl uninstall takes bayma off again, and with --purge, REPL sessions' state too.

Then you can use bayma. Each runtime has a skill, bayma-runtime-*, on how to work in that runtime with bayma. Within a REPL session, an agent executes code in that runtime, including against legacy software. For example, in the C++ runtime, with libardour, it can run a headless digital audio workstation:

npx skills add eaucoin/bayma --skill bayma-runtime-cpp bayma-platform-ardour

or with MLT++, a headless non-linear editor for video:

npx skills add eaucoin/bayma --skill bayma-runtime-cpp bayma-platform-mltpp

Or in the Python runtime, with bpy, it can model, animate, and render 3D scenes in a headless Blender:

npx skills add eaucoin/bayma --skill bayma-runtime-python bayma-platform-bpy

Each of these is a bayma-platform-* skill: one per platform, meaning an application or service an agent drives through its API. The skill shows where that API's reference is, and keeps what the platform needs in its own folder rather than being bundled with bayma.

Within each of the two namespaces, the skills share a similar structure, which makes it easier to add new runtimes and platforms.

Related MCP server: mcp-python-repl

Development

See package.json for the development scripts, Dockerfile for the image, packages/cli for the bayma command npm publishes as bayma-repl, .github/workflows/ for the GitHub Actions workflows, and .agents/skills/development-observability/ for development observability.