Bun Docs MCP

Bun Docs MCP for Zed

Search Bun documentation directly in Zed using the Model Context Protocol (MCP).

Important

Zed started supporting remote MCP servers since https://github.com/zed-industries/zed/pull/39021, released in Zed v0.214.5.
If you encounter issues using this extension, please submit an issue, and use the official remote server directly:

{
  "context_servers": {
    "bun-docs": {
      "url": "https://bun.com/docs/mcp",
      "enabled": true,
      "headers": {},
    },
  },
}

It is unfortunately not (yet) possible for extension authors to provide custom server URLs in the extension manifest.

Features

• 🔍 Search Bun Docs - Query Bun documentation from Zed Assistant
• ⚡ Pure Rust - Native binary with automatic download from GitHub Releases

Installation

From Zed Extensions (Coming Soon)

1. Open Zed
2. Cmd+Shift+X (macOS) or
   Ctrl+Shift+X (Linux/Windows)
   → Extensions
3. Search: "Bun Docs MCP"
4. Click Install

As Dev Extension (Local Development)

# Clone this repository
git clone https://github.com/kjanat/bun-docs-mcp-zed
cd bun-docs-mcp-zed

Then, install in Zed:

• Press Cmd+Shift+P (macOS) or
  Ctrl+Shift+P (Linux/Windows)
• Type: "zed: install dev extension"
• Select this directory

No build required! The extension auto-downloads the Rust binary from GitHub Releases on first use.

Usage

1. Open Assistant:
   Cmd+Shift+A (macOS) or
   Ctrl+Shift+A (Linux/Windows)
2. Enable Context: Click context dropdown → Enable "bun-docs-mcp"
3. Ask Questions: "How does Bun.serve work?"

Example Queries

• How does Bun.serve work?
• Explain Bun's WebSocket support
• What are Bun's TCP APIs?
• How do I use Bun.file?
• Show me Bun.spawn examples

Architecture

flowchart TD
    A["🔧 Zed Extension (WASM)<br/>• Auto-downloads binary<br/>• Platform detection<br/>• Daily update checks<br/>• Size: 171 KB"]
    B["📦 GitHub Releases<br/>kjanat/bun-docs-mcp-proxy<br/>• 6 platforms supported<br/>• ~1.3 MB compressed"]
    C["⚙️ Rust MCP Proxy (Native)<br/>• stdio ↔ HTTP ↔ SSE<br/>• 2.7 MB extracted<br/>• 4ms startup"]
    D["🌐 Bun Docs API<br/>https://bun.com/docs/mcp"]

    A -->|"downloads from"| B
    B -->|"extracts to /work/"| C
    C -->|"queries"| D

How It Works

1. Extension: Zed loads the WASM extension from this repo
2. Auto-Download: On first use, downloads platform-specific binary from GitHub Releases
3. Proxy Binary: Rust binary translates between:
   • Zed's stdin/stdout (JSON-RPC)
   • Bun Docs HTTP API (SSE responses)
4. Search: Queries Bun documentation and returns results

Supported Platforms

All platforms auto-detected and supported:

Static Linux builds (musl) also available.

Development

Project Structure

bun-docs-mcp-zed/
├── extension.toml      # Zed extension metadata
├── Cargo.toml          # Rust build configuration
├── src/
│   └── lib.rs          # Extension (auto-downloads proxy binary)
├── ARCHITECTURE.md     # Technical architecture
└── README.md           # This file

Proxy implementation: Separate repo at kjanat/bun-docs-mcp-proxy

Building

# Build extension WASM
cargo build --release --lib

# Extension auto-downloads proxy binary from GitHub
# No need to build proxy locally!

Testing

# Install as dev extension in Zed
# Cmd+Shift+P (macOS) or Ctrl+Shift+P (Linux/Windows) → "zed: install dev extension"
# Select this directory

# Enable in Assistant and test
# Open Assistant → Enable "bun-docs-mcp"
# Ask: "How does Bun.serve work?"

Technical Details

MCP Protocol: JSON-RPC 2.0 over stdio
Transport: Server-Sent Events (SSE) over HTTPS
API Endpoint: https://bun.com/docs/mcp
Binary Source: Auto-downloaded from GitHub Releases

For detailed architecture information, see ARCHITECTURE.md.

Troubleshooting

Extension won't enable

Check Zed log:
Cmd+Shift+P (macOS) or
Ctrl+Shift+P (Linux/Windows)
→ "zed: open log"

Common issues:

• First use takes 2-3 seconds (downloading binary)
• Network issues prevent download → Check internet connection
• Binary not for your platform → Check supported platforms above

Binary downloaded but won't run

Find the binary location:

The extension stores the binary in Zed's extension work directory. The exact path varies by platform:

• Linux: ~/.local/share/zed/extensions/work/bun-docs-mcp/bun-docs-mcp-proxy/
• macOS: ~/Library/Application Support/Zed/extensions/work/bun-docs-mcp/bun-docs-mcp-proxy/
• Windows: %APPDATA%\Zed\extensions\work\bun-docs-mcp\bun-docs-mcp-proxy\

Verify binary exists (Linux/macOS):

ls -lh ~/.local/share/zed/extensions/work/bun-docs-mcp/bun-docs-mcp-proxy/
# Should show: bun-docs-mcp-proxy (executable)

Test manually (Linux/macOS):

~/.local/share/zed/extensions/work/bun-docs-mcp/bun-docs-mcp-proxy/bun-docs-mcp-proxy <<< '{"jsonrpc":"2.0","id":1,"method":"tools/list"}'
# Should return: {"jsonrpc":"2.0","id":1,"result":{"tools":[...]}}

Note: Replace paths with your platform-specific location from above.

Why Rust?

• Boredom: Why not...

See ARCHITECTURE.md for migration history and technical details.

Contributing

Contributions welcome!

Proxy implementation: kjanat/bun-docs-mcp-proxy
Extension: This repository

License

MIT

Credits

• Zed Editor - Extensible code editor
• Bun - Fast JavaScript runtime
• Model Context Protocol - LLM integration standard
• Bun Docs MCP Server - Official Bun documentation API

Ready to search Bun docs in Zed! Install the extension and start asking questions. 🚀