Sunstone Weave: Local Semantic Code Search MCP server

blackwindow-weave-mcp

Semantic search over the folders on your machine, for any MCP client. The server cuts source code and documentation into passages, embeds them with Motherlode, a 33M-parameter code-search encoder, on your CPU, and answers questions such as "where is a pairing line parsed into url, key and name" with file paths, line ranges and the passages themselves.

The only network requests are to huggingface.co on the first run: six requests, which leave five files, 133,752,819 bytes, in the cache. With the files cached, a run makes none.

This is the weave from Black Window and the Sunstone VS Code extension, packaged for clients that speak the Model Context Protocol. It runs on macOS, Linux and Windows with Node 20 or later.

Install

Install it once from a terminal, before adding it to a client. This installs the package and ONNX Runtime and prints the version once the runtime has loaded:

npx -y blackwindow-weave-mcp@0.1.2 --version

On GitHub's hosted runners, from an empty npm cache, this first install took 7 to 13 s on Linux and macOS and 55 to 69 s on Windows. Clients wait a limited time for a server to start (the MCP SDK's default is 60 s), and a client that stops waiting in the middle of an install can leave a broken copy in npm's cache (see Troubleshooting). Once installed, the server starts in under 3 s.

Keep the version in the client's configuration the same as here. With a version given, npx starts the copy it installed; with the bare name, npx (npm 11) looks for a newer version on every start and installs it while the client waits.

On Linux x64, ONNX Runtime also downloads 236 MB of CUDA libraries during the install. This server runs on the CPU and never loads them, so you can skip them:

ONNXRUNTIME_NODE_INSTALL=skip npx -y blackwindow-weave-mcp@0.1.2 --version

Add it to a client

macOS and Linux

Claude Code:

claude mcp add weave -- npx -y blackwindow-weave-mcp@0.1.2 --folder /path/to/your/repo

VS Code, in .vscode/mcp.json:

{
  "servers": {
    "weave": { "type": "stdio", "command": "npx", "args": ["-y", "blackwindow-weave-mcp@0.1.2", "--folder", "${workspaceFolder}"] }
  }
}

Cursor, Claude Desktop, Windsurf and most other clients:

{
  "mcpServers": {
    "weave": { "command": "npx", "args": ["-y", "blackwindow-weave-mcp@0.1.2", "--folder", "/path/to/your/repo"] }
  }
}

Windows

On Windows npx is a batch file, which a client can only start through cmd /c. Claude Code:

claude mcp add weave -- cmd /c npx -y blackwindow-weave-mcp@0.1.2 --folder C:\path\to\your\repo

Cursor, Claude Desktop, Windsurf and most other clients:

{
  "mcpServers": {
    "weave": { "command": "cmd", "args": ["/c", "npx", "-y", "blackwindow-weave-mcp@0.1.2", "--folder", "C:/path/to/your/repo"] }
  }
}

In VS Code the same command and args go under servers in .vscode/mcp.json, with "type": "stdio".

Installed globally

npm install -g blackwindow-weave-mcp@0.1.2 installs a blackwindow-weave-mcp command, which a client can start directly (cmd /c blackwindow-weave-mcp on Windows). To run from this repository instead of npm, replace blackwindow-weave-mcp@0.1.2 in the arguments with github:space-bacon/blackwindow-weave-mcp.

Platforms

Shortened. The full README is on GitHub.