envy-mcp-hello

A tiny public MCP server backed by an Envy-managed Modal sandbox. It exposes one hello environment and the standard Envy MCP tools:

create_sandbox · kill_sandbox · bash · read · write · edit · glob · grep

This example pins the current FastMCP 4 prerelease (4.0.0b3) so the public deployment exercises the v4 server and client protocol.

Deploy it

1. Create a Modal token in the modal-labs workspace.

2. In this GitHub repository, add these Actions secrets under Settings → Secrets and variables → Actions:

   • MODAL_TOKEN_ID

   • MODAL_TOKEN_SECRET

3. Push to main, or run Deploy MCP server manually from the Actions tab.

The workflow installs Envy from the public aaazzam/envy repository, runs the declaration test, and deploys the modal_app in devboxes.py to Modal.

The deployed MCP URL is:

https://modal-labs-aaazzam-dev--envy-mcp-hello-serve.modal.run/mcp

The endpoint is intentionally public for experimentation. Do not put secrets or private source code in the hello sandbox.

Related MCP server: Modal MCP

Try it

Point an MCP client at the URL and call:

1. create_sandbox with environment: "hello"

2. write /tmp/hello/message.txt with hello from MCP

3. read, edit, bash, glob, or grep against that file

4. read /tmp/hello/README.md or run /tmp/hello/hello.py

5. kill_sandbox when finished

The sandbox is ephemeral, uses /tmp/hello as its working directory, and is seeded with a small README.md and hello.py hello-world fixture.

Local validation

With Python and the MCP extra installed:

python -m unittest discover -s tests

Live Modal integration is deliberately not part of the GitHub Action. The Action deploys the public control plane; sandbox creation happens when an MCP client calls create_sandbox.