A high-performance Rust-based Model Context Protocol (MCP) server that provides comprehensive JSON file operations optimized for LLM interactions. This server enables LLMs to efficiently read, write, query, and manipulate JSON files with support for extremely large datasets and advanced querying capabilities.
- 📖 json-read: Read JSON files with optional JSONPath filtering and pagination
- ✏️ json-write: Write or update JSON files with multiple merge strategies
- 🔍 json-query: Execute complex JSONPath queries with various output formats
- ✅ json-validate: Validate JSON structure and syntax with detailed diagnostics
- ❓ json-help: Interactive help system with comprehensive examples and troubleshooting
- Large File Support: Efficient pagination and streaming for files of any size
- JSONPath Querying: Full JSONPath support for complex data extraction and filtering
- Flexible Writing: Multiple modes (replace, merge_shallow, merge_deep, append) with backup options
- LLM-Optimized: Detailed error messages and usage examples for optimal LLM interaction
- Memory Efficient: Smart pagination prevents memory overflow on large datasets
- MCP Compliant: Full Model Context Protocol support with proper error handling
- Debug Logging: File-based debug logging for troubleshooting without violating MCP protocol
cargo install json-mcp-server
# Linux/macOS
curl -fsSL https://raw.githubusercontent.com/ciresnave/json-mcp-server/main/scripts/install.sh | bash
# Windows PowerShell
iwr https://raw.githubusercontent.com/ciresnave/json-mcp-server/main/scripts/install.ps1 | iex
Download platform-specific binaries from GitHub Releases:
- Windows:
json-mcp-server-v{version}-x86_64-pc-windows-msvc.zip
- macOS:
json-mcp-server-v{version}-x86_64-apple-darwin.tar.gz
- Linux:
json-mcp-server-v{version}-x86_64-unknown-linux-gnu.tar.gz
# Download and install .deb package
wget https://github.com/ciresnave/json-mcp-server/releases/latest/download/json-mcp-server_*_amd64.deb
sudo dpkg -i json-mcp-server_*_amd64.deb
# Download and install .rpm package
wget https://github.com/ciresnave/json-mcp-server/releases/latest/download/json-mcp-server-*.x86_64.rpm
sudo rpm -i json-mcp-server-*.x86_64.rpm
# Manual install using PKGBUILD
wget https://github.com/ciresnave/json-mcp-server/releases/latest/download/PKGBUILD
makepkg -si
# Clone the repository
git clone https://github.com/ciresnave/json-mcp-server.git
cd json-mcp-server
# Build the project
cargo build --release
# Run the server
cargo run
After installation, verify it works:
json-mcp-server --version
json-mcp-server --help
The JSON MCP Server communicates via JSON-RPC over stdin/stdout following the Model Context Protocol specification.
-
Start the server:
cargo run
-
Get help: Use the
json-help
tool to learn about available functionality:{ "jsonrpc": "2.0", "id": 1, "method": "tools/call", "params": { "name": "json-help", "arguments": {"topic": "overview"} } }
{
"name": "json-read",
"arguments": {
"file_path": "./data.json",
"json_path": "$.users[*].name",
"format": "pretty"
}
}
{
"name": "json-write",
"arguments": {
"file_path": "./config.json",
"data": {"setting": "value", "enabled": true},
"mode": "merge"
}
}
{
"name": "json-query",
"arguments": {
"file_path": "./products.json",
"query": "$.products[?(@.price > 100)].name",
"format": "table"
}
}
{
"name": "json-read",
"arguments": {
"file_path": "./large-dataset.json",
"json_path": "$.records[*].id",
"limit": 1000,
"offset": 0
}
}
Read and parse JSON files with optional JSONPath filtering and pagination.
Parameters:
file_path
(string, required): Path to JSON filejson_path
(string, optional): JSONPath expression for filteringstart_index
(integer, optional): Starting index for pagination (default: 0)limit
(integer, optional): Maximum items to return (default: 1000)output_format
(string, optional): Output format - "json", "pretty", "compact" (default: "json")
Write or update JSON files with flexible merge strategies.
Parameters:
file_path
(string, required): Path to JSON filecontent
(string, required): JSON content to writemode
(string, optional): Write mode - "replace", "merge_shallow", "merge_deep", "append" (default: "replace")
Execute JSONPath queries on JSON files with various output formats.
Parameters:
file_path
(string, required): Path to JSON filejson_path
(string, required): JSONPath query expressionoutput_format
(string, optional): Output format - "json", "pretty", "compact", "csv", "markdown" (default: "json")
Validate JSON file structure and syntax.
Parameters:
file_path
(string, required): Path to JSON file to validate
Get comprehensive help about available tools and JSONPath syntax.
Parameters:
topic
(string, optional): Help topic - "overview", "tools", "jsonpath", "examples", "troubleshooting" (default: "overview")
The server supports full JSONPath syntax for querying JSON data:
$
- Root element.field
- Child field access[index]
- Array index access[*]
- All array elements..field
- Recursive descent[?(@.field > value)]
- Filter expressions{field1, field2}
- Projection
# Get all user names
$.users[*].name
# Filter users over 25
$.users[?(@.age > 25)]
# Get nested data
$.data.items[*].details.price
# All prices anywhere in document
$..price
# Complex filtering
$.products[?(@.category == 'electronics' && @.price < 500)].name
- Files of any size: The
json-read
tool automatically uses streaming for memory efficiency - Line-delimited JSON: Automatically detected and processed efficiently
- Memory usage: Streaming keeps memory usage constant regardless of file size
- Use specific JSONPath queries to filter data early
- Set reasonable limits when processing large datasets
- Use offset for pagination through large result sets
- The server automatically optimizes for file size and available memory
The server provides detailed error messages to help diagnose issues:
- File not found: Clear path resolution guidance
- JSON syntax errors: Line and column information when available
- JSONPath errors: Syntax validation and suggestions
- Memory issues: Guidance on using streaming alternatives
The JSON MCP Server works with any MCP-compatible client. Detailed configuration guides are available in the examples/mcp_clients/
directory:
- VS Code with GitHub Copilot - Complete setup guide
- Claude Desktop - Configuration and usage examples
- Generic MCP Client - Universal configuration guide
- Custom Implementation - Build your own client
VS Code + GitHub Copilot:
{
"mcp.servers": {
"json-mcp-server": {
"path": "json-mcp-server"
}
}
}
Claude Desktop:
{
"mcpServers": {
"json-mcp-server": {
"command": "json-mcp-server",
"args": []
}
}
}
For detailed setup instructions, troubleshooting, and advanced configurations, see the respective client guides in the examples/mcp_clients/
directory.
json-mcp-server/
├── src/ # Source code
│ ├── main.rs # Application entry point and MCP server
│ ├── lib.rs # Library exports for testing
│ ├── mcp/ # MCP protocol implementation
│ │ ├── mod.rs
│ │ ├── protocol.rs # Protocol definitions and types
│ │ └── server.rs # MCP server implementation
│ └── json_tools/ # JSON tool implementations
│ ├── mod.rs
│ ├── handler.rs # Tool coordination and help system
│ ├── operations.rs # Read/write/validate operations
│ ├── query.rs # JSONPath querying with multiple formats
│ └── streaming.rs # Large file streaming and pagination
├── tests/ # Integration tests
│ └── integration_tests.rs
├── examples/ # Example configurations and data
│ ├── mcp_clients/ # Client configuration guides
│ │ ├── vscode.md # VS Code setup
│ │ ├── claude-desktop.md
│ │ ├── github-copilot.md
│ │ ├── generic.md # Generic MCP client setup
│ │ ├── client_implementation.md
│ │ └── python_client.py
│ ├── sample-data.json # Sample test data
│ ├── test-commands.jsonl
│ └── test-output.json
├── dev_tools/ # Development and testing utilities
│ ├── README.md # Development tools documentation
│ └── testing/ # Test scripts and utilities
│ ├── test_all_tools.py
│ ├── test_multiple_instances.py
│ ├── test_json_help.py
│ └── [other test files]
├── Cargo.toml # Rust project configuration
└── README.md # This file
# Development build
cargo build
# Release build
cargo build --release
# Run tests
cargo test
# Check for issues
cargo check
tokio
: Async runtimeserde
/serde_json
: JSON serializationjsonpath-rust
: JSONPath query supportanyhow
: Error handlingclap
: Command line parsing
This project is licensed under the MIT OR Apache-2.0 license.
Contributions are welcome! Please ensure:
- Code follows Rust conventions
- All tests pass
- New features include appropriate tests
- Documentation is updated for new functionality
For issues, questions, or contributions, please refer to the project repository.