# hmr

An MCP server that serves the hmr docs — hot module reload and reactive programming for Python — so your agent stops guessing at the API.

- MCP server · `type=mcp` · Claude Code, Codex, Cursor, GitHub Copilot, Windsurf (Devin Desktop), Cline, Zed, Gemini CLI · ★ 59
- Author: promplate
- License: not stated · policy=link-only · description only; the file stays with the author
- Source: https://github.com/promplate/hmr
- Updated: 2026-10-23
- HTML: https://affpapa.org/en/nevibecode/mcp/hmr

## What it does

The server hands your agent the documentation for hmr, a reactive programming engine for Python and a hot-reload tool built on top of it. That covers the core library and the packages around it: `uvicorn-hmr` for ASGI apps, `mcp-hmr` for MCP servers, `hmr-daemon` for refreshing modules in the background.

It runs over HTTP, so there is nothing to install locally. In Claude the whole setup is `claude mcp add --transport http hmr https://pyth-on-line.promplate.dev/hmr/mcp`. Cursor and GitHub Copilot take a JSON block in their config, while Codex and Gemini CLI use their own `mcp add` command with the `http` transport type.

hmr itself tracks dependencies at runtime rather than by static analysis: change a variable and only the modules that depend on it rerun, with app state left intact. Circular dependencies can still misbehave in edge cases, and the author advises caution if your `__init__.py` holds a lot of code.

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

## Install

### Claude Code (native platform)

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

### Codex

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

### Cursor

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

### GitHub Copilot

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

### Gemini CLI

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

## When to use it
- look up hmr behaviour without reading the library source
- compare hmr against `uvicorn --reload` and `watchfiles`
- pick the right ecosystem package for an ASGI or MCP server
- wire Python library docs into an agent over HTTP
- understand how runtime dependency tracking works

## Example prompts
- How does hmr track dependencies between modules at runtime?
- Show me how to run a FastAPI app with `uvicorn-hmr`
- What does hmr do differently from `uvicorn --reload`?

## Similar
- [Serena MCP: the IDE for your agent](https://affpapa.org/en/nevibecode/mcp/serena-mcp-the-ide-for-your-agent.md) — MCP server · ★ 30677
- [Compiler Explorer](https://affpapa.org/en/nevibecode/mcp/compiler-explorer.md) — MCP server · ★ 19148
- [Claude Code Explorer MCP](https://affpapa.org/en/nevibecode/mcp/claude-code-explorer-mcp.md) — MCP server · ★ 6235
- [Tolgee](https://affpapa.org/en/nevibecode/mcp/tolgee.md) — MCP server · ★ 4139
- [jshookmcp](https://affpapa.org/en/nevibecode/mcp/jshookmcp.md) — MCP server · ★ 2061
- [pyscn](https://affpapa.org/en/nevibecode/mcp/pyscn.md) — MCP server · ★ 1096

---
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