mcp-json-tools

An MCP (Model Context Protocol) server that provides JSON and data manipulation tools for AI agents. Designed for use with Claude Code, Claude Desktop, and any MCP-compatible client.

Tools

Tool	Description
json_validate	Validate JSON data against a JSON Schema, returning detailed errors with paths
json_diff	Compare two JSON objects, showing additions, removals, and changes with paths
json_transform	Transform JSON with pick, rename, flatten, and unflatten operations
csv_to_json	Convert CSV text to a JSON array with configurable headers, delimiters, and type casting
json_to_csv	Convert a JSON array of objects to CSV text
yaml_to_json	Convert YAML text to JSON
json_to_yaml	Convert JSON text to YAML

Installation

npm install
npm run build

Usage with Claude Code

claude mcp add json-tools -- node D:/products/mcp-servers/mcp-json-tools/dist/index.js

Usage with Claude Desktop

Add the following to your Claude Desktop configuration file:

Windows: %APPDATA%\Claude\claude_desktop_config.json macOS: ~/Library/Application Support/Claude/claude_desktop_config.json

{
  "mcpServers": {
    "json-tools": {
      "command": "node",
      "args": ["D:/products/mcp-servers/mcp-json-tools/dist/index.js"]
    }
  }
}

Tool Details

json_validate

Validate JSON data against a JSON Schema. Returns a valid boolean and an array of errors, each with the field path, message, and schema keyword that failed.

Parameters:

• data (string) — JSON data to validate
• schema (string) — JSON Schema to validate against

json_diff

Compare two JSON objects and produce a structured diff. Each difference includes the dot-notation path, the type of change (added, removed, or changed), and the old/new values.

Parameters:

• original (string) — Original JSON object
• modified (string) — Modified JSON object

json_transform

Apply transformations to JSON data. Supports four operations:

• pick — Extract specific fields by dot-notation paths
• rename — Rename top-level keys using a mapping object
• flatten — Flatten nested objects into dot-separated keys
• unflatten — Restore dot-separated keys into nested objects

Parameters:

• data (string) — JSON data to transform
• operation (string) — One of: pick, rename, flatten, unflatten
• fields (string[]) — For pick: field paths to extract
• mapping (object) — For rename: old-to-new key mapping
• separator (string) — For flatten/unflatten: separator character (default: ".")

csv_to_json

Parse CSV text into a JSON array of objects.

Parameters:

• csv (string) — CSV text to convert
• hasHeaders (boolean) — Whether the first row is headers (default: true)
• delimiter (string) — Column delimiter (default: ",")
• castTypes (boolean) — Auto-cast numbers and booleans (default: false)

json_to_csv

Convert a JSON array of objects to CSV text. Headers are derived from the union of all object keys.

Parameters:

• data (string) — JSON array to convert
• delimiter (string) — Column delimiter (default: ",")
• includeHeaders (boolean) — Include header row (default: true)

yaml_to_json / json_to_yaml

Convert between YAML and JSON formats.

Parameters:

• yamlText / jsonText (string) — Text to convert
• indent (number) — Indentation spaces (default: 2)

License

MIT