JSON MCP Server

Node.js server implementing Model Context Protocol (MCP) for JSON operations.

Features

Query JSON files using jq notation with complex filters and transformations
Generate JSON schemas automatically from existing JSON data
Validate JSON schemas to ensure they are properly formed
S3 sync support for remote JSON file synchronization
Support for both stdio and HTTP transport protocols

Note: The server requires jq binary to be installed on your system and will only allow operations on files with absolute paths.

Related MCP server: JSON MCP Server

Prerequisites

🚨 Required: Install jq binary on your system

macOS:

brew install jq

Linux:

# Ubuntu/Debian sudo apt-get install jq # CentOS/RHEL/Fedora sudo yum install jq # or sudo dnf install jq # Arch Linux sudo pacman -S jq

Windows:

Winget (recommended)

# Winget (recommended) winget install --id=jqlang.jq # Chocolatey choco install jq # Scoop scoop instal jq

Verify installation:

jq --version # Should output something like: jq-1.6

API

Resources

file://json: JSON file operations interface

Tools

query_json
- Execute jq queries on JSON files with complex filters and transformations
- Input:
  - filePath (string, optional if default set): Absolute path to JSON file
  - query (string): jq query expression
- Example queries:
  - "." - Return entire JSON (not recommended)
  - ".users" - Get users array
  - ".users[0].name" - Get first user's name
  - ".users[] | select(.active == true)" - Filter active users
  - ".[].price | add" - Sum all prices
generate_json_schema
- Generate JSON schemas automatically from existing JSON data using genson-js
- Input: filePath (string, optional if default set): Absolute path to JSON file
- Returns: Complete JSON schema that describes the structure of your data
validate_json_schema
- Validate that JSON schemas are properly formed using AJV
- Input:
  - schema (object): JSON schema object to validate, OR
  - schemaFilePath (string): Path to file containing JSON schema
- Returns: Validation result with detailed feedback

Usage with Claude Desktop

Add this to your claude_desktop_config.json:

NPX (Recommended)

Stdio Transport (Default):

{ "mcpServers": { "json-mcp-server": { "command": "npx", "args": [ "-y", "@berrydev-ai/json-mcp-server", "--verbose=true", "--file-path=/absolute/path/to/your/data.json" ] } } }

HTTP Transport:

{ "mcpServers": { "json-mcp-server": { "command": "npx", "args": [ "-y", "@berrydev-ai/json-mcp-server", "--transport=http", "--port=3000", "--verbose=true", "--file-path=/absolute/path/to/your/data.json" ] } } }

Local Development

Stdio Transport:

{ "mcpServers": { "json-mcp-server": { "command": "node", "args": [ "/path/to/json-mcp-server/index.js", "--verbose=true", "--file-path=/absolute/path/to/your/data.json" ] } } }

HTTP Transport:

{ "mcpServers": { "json-mcp-server": { "command": "node", "args": [ "/path/to/json-mcp-server/index.js", "--transport=http", "--port=3000", "--host=localhost", "--verbose=true", "--file-path=/absolute/path/to/your/data.json" ] } } }

With S3 Sync (Optional)

{ "mcpServers": { "json-mcp-server": { "command": "npx", "args": [ "-y", "@berrydev-ai/json-mcp-server", "--s3-uri=s3://your-bucket/data.json", "--file-path=/absolute/path/to/local-data.json", "--aws-region=us-east-1", "--verbose=true" ], "env": { "AWS_ACCESS_KEY_ID": "your-access-key-id", "AWS_SECRET_ACCESS_KEY": "your-secret-access-key" } } } }

Command Line Usage

Start server locally (stdio transport - default):

npm start # Basic start with stdio transport npm run dev # Start with verbose logging and stdio transport node index.js --verbose=true --file-path=/absolute/path/to/data.json

Start server with HTTP transport:

npm run start:http # Start HTTP server with verbose logging npm run dev:http # Start HTTP server on port 3000 with verbose logging node index.js --transport=http --verbose=true --port=3000 --host=localhost

Transport options:

--transport=stdio # Default: stdin/stdout communication --transport=http # HTTP server with session management --port=3000 # HTTP server port (default: 3000) --host=localhost # HTTP server host (default: localhost) --cors-origin=* # CORS allowed origins (default: *)

Testing:

npm test # Run test setup (creates test files and validates jq) node test.js # Same as above

MCP Inspector (for debugging):

npm run inspect:local # Test local development version npm run inspect:published # Test published npm package

Build

NPM Installation:

npm install -g @berrydev-ai/json-mcp-server

Local Development:

git clone https://github.com/berrydev-ai/json-mcp-server.git cd json-mcp-server npm install

Dependencies

@modelcontextprotocol/sdk: MCP protocol implementation
node-jq: Node.js wrapper for jq binary (requires system jq installation)
genson-js: JSON schema generation
ajv: JSON schema validation
commander: Command line argument parsing
which: Binary path detection utility
@aws-sdk/client-s3: AWS S3 client for optional file synchronization
express: HTTP server framework for HTTP transport
cors: Cross-origin resource sharing middleware

Example JSON Data

Create a test file test-data.json:

{ "users": [ { "id": 1, "name": "John Doe", "email": "john@example.com", "active": true, "roles": ["user", "admin"] }, { "id": 2, "name": "Jane Smith", "email": "jane@example.com", "active": false, "roles": ["user"] } ], "metadata": { "version": "1.0", "created_at": "2024-01-01T00:00:00Z" } }

License

This MCP server is licensed under the ISC License. This means you are free to use, modify, and distribute the software, subject to the terms and conditions of the ISC License. For more details, please see the LICENSE file in the project repository.

JSON MCP Server

JSON MCP Server

Features

Prerequisites

Winget (recommended)

API

Resources

Tools

Usage with Claude Desktop

NPX (Recommended)

Local Development

With S3 Sync (Optional)

Command Line Usage

Build

Dependencies

Example JSON Data

License

Resources

Appeared in Searches

New MCP Servers

Latest Blog Posts

MCP directory API