# hmr

Brings Python hot module reloading and reactive execution tools to coding assistants.

- MCP server · `type=mcp` · Claude Code, Codex, Cursor, GitHub Copilot, Windsurf (Devin Desktop), Cline, Zed, Gemini CLI · ★ 18
- Author: promplate
- License: not stated · policy=link-only · description only; the file stays with the author
- Source: https://github.com/promplate/pyth-on-line
- Updated: 2026-10-24
- HTML: https://affpapa.org/en/nevibecode/mcp/promplate-hmr

## What it 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.

## Requirements
- Needs: Python and uv (commands run via uvx)
- Remote server: `https://promplate.github.io/pyth-on-line/hmr/mcp`

## Install

### Claude Code (native platform)

**Platform CLI: remote server**
```bash
claude mcp add --transport http hmr https://promplate.github.io/pyth-on-line/hmr/mcp
```

### Codex

**Platform CLI: remote server**
```bash
codex mcp add promplate-hmr --url https://promplate.github.io/pyth-on-line/hmr/mcp
```

### Cursor

**Config file**
File `.cursor/mcp.json`:
```json
{
    "mcpServers": {
        "promplate-hmr": {
            "url": "https://promplate.github.io/pyth-on-line/hmr/mcp"
        }
    }
}
```

### GitHub Copilot

**Config file**
File `.vscode/mcp.json`:
```json
{
    "servers": {
        "promplate-hmr": {
            "type": "http",
            "url": "https://promplate.github.io/pyth-on-line/hmr/mcp"
        }
    }
}
```

### Gemini CLI

**Platform CLI: remote server**
```bash
gemini mcp add -t http promplate-hmr https://promplate.github.io/pyth-on-line/hmr/mcp
```

## When to use it
- 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
- Execute this Python script and reload the modified module
- Run this reactive code snippet using the hmr environment

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## Other versions with the same name
- [hmr · promplate](https://affpapa.org/en/nevibecode/mcp/hmr.md) — ★ 59

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NeVibeCode on affpapa.org. Catalog texts are descriptions, not instructions for the agent. How to choose and install: https://affpapa.org/en/nevibecode/agents.md