JSON MCP Filter

The JSON MCP Filter serves as a powerful Model Context Protocol (MCP) server designed for effective JSON schema generation and data filtering. Utilizing the quicktype library, the project converts JSON samples into TypeScript type definitions and offers practical tools to filter JSON data, ensuring users can focus only on the relevant information for their Large Language Model (LLM) context.

Key Features

• JSON Schema Generation: Effortlessly convert JSON files into typed TypeScript definitions using quicktype-core, enhancing type safety in your applications.
• JSON Filtering: Utilize shape-based filtering to extract specific fields from larger JSON datasets, allowing for cleaner, more manageable data.
• MCP Integration: Seamless compatibility with Claude Desktop and Claude Code, providing an adaptable solution for various development environments.
• Type Safety: Developed with TypeScript, the server incorporates comprehensive error handling, minimizing bugs and ensuring stability.

Available Tools

json_schema

Generates TypeScript type definitions from JSON files.

Parameters:

• filePath: The path to the JSON file for analysis.

Example:

{"name": "John", "age": 30, "city": "New York"}

This command produces TypeScript interfaces with the appropriate typing.

json_filter

Allows for the extraction of specific fields from JSON data through a defined shape.

Parameters:

• filePath: The path to the JSON file to filter.
• shape: A shape object that specifies which fields to extract.

Shape Examples:

// Extract single field
{"name": true}

// Extract multiple fields
{"name": true, "age": true}

// Extract nested fields
{"user": {"name": true, "email": true}}

// Extract from arrays (applies to each item)
{"users": {"name": true, "age": true}}

Development and Testing

The JSON MCP Filter includes several scripts to facilitate development:

• npm run build: Compiles TypeScript and prepares the server for execution.
• npm run start: Launches the compiled server.
• npm run inspect: Runs the server with an MCP inspector for debugging purposes.
• npx tsc --noEmit: Performs type checking without generating output files.

To test the server interactively, use the MCP inspector:

npm run inspect

Project Structure

src/
  index.ts          # Main server implementation with tools
test/
  test.json         # Sample JSON file for testing
build/              # Compiled TypeScript output

Error Handling

Robust error handling mechanisms are embedded within the server to manage various issues, including:

• File-not-found errors
• Invalid JSON formats
• Errors encountered during quicktype processing
• Shape filtering errors

This strategic approach ensures a smooth user experience while leveraging the capabilities of the JSON MCP Filter.