Add JSON MCP Filter to README.md

[kehvinbehvin]

Description

This PR adds a reference to a JSON filtering MCP server.

Motivation and Context

Existing JSON MCP tooling are great for performing complex JSON file processing. However, they are not optimised to help LLMs gain understanding of the JSON data efficiently especially when the data your LLM needs is deeply nested / mixed together with irrelevant data.

JSON MCP filter solves this problem in 2 ways

• Provides LLMs a high level understanding of the JSON file and information structure by reverse engineering the JSON schema into Typescript Types/Interfaces using https://github.com/glideapps/quicktype
• Allows the LLM to filter out noisy data from the original JSON file by providing its desired schema as an JSON object.

How Has This Been Tested?

How Has This Been Tested?

• Package verification: Confirmed json-mcp-filter@latest installs and runs correctly via npx
• MCP integration: Tested with Claude Code and Claude Desktop using both local build and published package
• Core functionality: Verified JSON schema generation and schema filtering with test json files. Error handling implemented for invalid json files and invalid file paths.

Breaking Changes

None

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation update

Checklist

• I have read the MCP Protocol Documentation
• My changes follows MCP security best practices
• I have updated the server's README accordingly
• I have tested this with an LLM client
• My code follows the repository's style guidelines
• New and existing tests pass locally
• I have added appropriate error handling
• I have documented all environment variables and configuration options

Additional context

The JSON MCP Filter server operates entirely on local file systems without requiring external API credentials or network connectivity. The server implements comprehensive input validation and path resolution to ensure secure local file access. All operations include appropriate error handling for invalid JSON formats, missing files, and malformed shape queries, with detailed error messages to guide users in correcting their requests.

[olaservo]

Thanks for your contribution to the servers list. This has been merged in this combined PR: #2475

This is a new process we're trying out, so if you see any issues feel free to re-open the PR and tag me.