hmr · promplate — Claude Code MCP server: what it does, how to install
Brings Python hot module reloading and reactive execution tools to coding assistants.
claude mcp add --transport http hmr https://promplate.github.io/pyth-on-line/hmr/mcpWhat hmr does
The server provides an environment for running Python interactively with hot module reloading. Modified files refresh immediately without restarting the entire runtime. It keeps active variables intact during iterative testing.
It connects over HTTP directly to a hosted GitHub Pages endpoint, which requires an active internet connection to function. The implementation relies on the hmr library and the Pyodide runtime from the Pythonline project.
What it helps with
- reload Python modules on the fly without resetting runtime state
- execute interactive Python scripts inside Pyodide
- debug reactive Python functions through agent tools
Example prompts for the agent
- Execute this Python script and reload the modified module
- Run this reactive code snippet using the hmr environment
How to install hmr
Platform CLI: remote server
claude mcp add --transport http hmr https://promplate.github.io/pyth-on-line/hmr/mcpPlatform CLI: remote server
codex mcp add promplate-hmr --url https://promplate.github.io/pyth-on-line/hmr/mcpConfig file
{
"mcpServers": {
"promplate-hmr": {
"url": "https://promplate.github.io/pyth-on-line/hmr/mcp"
}
}
}Config file
{
"servers": {
"promplate-hmr": {
"type": "http",
"url": "https://promplate.github.io/pyth-on-line/hmr/mcp"
}
}
}Platform CLI: remote server
gemini mcp add -t http promplate-hmr https://promplate.github.io/pyth-on-line/hmr/mcpStep by step, with commands for each platform: How to add an MCP server to Claude Code, Codex, Cursor, VS Code, Gemini CLI and more
Questions about hmr
How to install hmr in Claude Code?
Run claude mcp add --transport http hmr https://promplate.github.io/pyth-on-line/hmr/mcp in your terminal.
What does the hmr MCP server do?
It equips the assistant with tools for hot module reloading and reactive Python evaluation via Pyodide.
What transport endpoint does this server use?
It communicates over HTTP pointing to https://promplate.github.io/pyth-on-line/hmr/mcp.
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