LocalSynapse MCP Server Enables Claude to Search Local Documents Offline

LocalSynapse is an MCP server that enables Claude AI assistants to search through local files on your machine. It addresses the limitation of the official filesystem MCP, which requires exact file paths, by providing content-based search across thousands of documents.

What LocalSynapse Does

As an MCP server, LocalSynapse provides three main functions:

• search_files — searches inside document contents using hybrid BM25 + AI semantic search. For example, searching for "budget forecast" can find files containing "financial projection"
• search_filenames — fast filename and folder matching
• get_file_content — reads document content with metadata

The tool indexes Word, Excel, PowerPoint, PDF, and other document formats. All processing happens locally — no data leaves your machine, and no cloud services or API keys are required.

Setup and Configuration

LocalSynapse works with Claude Desktop, Claude Code, Cursor, and VS Code. Configuration involves adding it to your MCP servers configuration:

{
  "mcpServers": {
    "localsynapse": {
      "command": "C:\\path\\to\\LocalSynapse.exe",
      "args": ["mcp"]
    }
  }
}

After installing the application, it indexes your drives in the background. Once indexed, Claude can search across all your files.

Dual Functionality

The same binary serves two purposes: double-clicking opens a GUI for manual searching, while running with the mcp argument turns it into an MCP server. This provides two entry points from a single installation.

Currently, LocalSynapse is Windows-only and completely free with no feature limitations. It's a side project developed by a solo developer.