MCP JSON Tools MCP Server

Local setup required. This server has to be cloned and prepared on your machine before you register it in Claude Code.
1

Set the server up locally

Run this once to clone and prepare the server before adding it to Claude Code.

Run in terminal
npm install
npm run build
2

Register it in Claude Code

After the local setup is done, run this command to point Claude Code at the built server.

Run in terminal
claude mcp add mcp-json-tools -- node "<FULL_PATH_TO_MCP_JSON_TOOLS>/dist/index.js"

Replace <FULL_PATH_TO_MCP_JSON_TOOLS>/dist/index.js with the actual folder you prepared in step 1.

README.md

JSON and data manipulation tools for AI agents

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

Tools (7)

json_validateValidate JSON data against a JSON Schema, returning detailed errors with paths
json_diffCompare two JSON objects, showing additions, removals, and changes with paths
json_transformTransform JSON with pick, rename, flatten, and unflatten operations
csv_to_jsonConvert CSV text to a JSON array with configurable headers, delimiters, and type casting
json_to_csvConvert a JSON array of objects to CSV text
yaml_to_jsonConvert YAML text to JSON
json_to_yamlConvert JSON text to YAML

Configuration

claude_desktop_config.json
{"mcpServers": {"json-tools": {"command": "node", "args": ["path/to/mcp-json-tools/dist/index.js"]}}}

Try it

Validate this JSON string against the provided schema: [JSON data] and [Schema]
Compare these two JSON objects and tell me exactly what changed: [Object A] and [Object B]
Convert this CSV data into a clean JSON array: [CSV data]
Flatten this nested JSON object to make it easier to read: [JSON data]
Convert this JSON configuration into YAML format: [JSON data]

Frequently Asked Questions

What are the key features of MCP JSON Tools?

JSON schema validation with detailed error reporting. Structured JSON diffing with path-based change tracking. Data transformation including pick, rename, flatten, and unflatten. Bidirectional conversion between JSON, CSV, and YAML formats.

What can I use MCP JSON Tools for?

Validating API responses against predefined schemas during development. Comparing configuration files to identify specific changes. Converting legacy CSV exports into JSON for application ingestion. Cleaning and restructuring complex nested JSON data for easier processing.

How do I install MCP JSON Tools?

Install MCP JSON Tools by running: npm install && npm run build

What MCP clients work with MCP JSON Tools?

MCP JSON Tools works with any MCP-compatible client including Claude Desktop, Claude Code, Cursor, and other editors with MCP support.

Turn this server into reusable context

Keep MCP JSON Tools docs, env vars, and workflow notes in Conare so your agent carries them across sessions.

Need the old visual installer? Open Conare IDE.
Open Conare