Custom Context MCP Server

This Model Context Protocol (MCP) server provides tools for structuring and extracting data from text according to JSON templates.

Features

Text-to-JSON Transformation

- Group and structure text based on JSON templates with placeholders
- Extract information from AI-generated text into structured JSON formats
- Support for any arbitrary JSON structure with nested placeholders
- Intelligent extraction of key-value pairs from text
- Process AI outputs into structured data for downstream applications

Getting Started

Installation

npm install

Running the server

npm start

For development with hot reloading:

npm run dev:watch

Usage

This MCP server provides two main tools:

1. Group Text by JSON (group-text-by-json)

This tool takes a JSON template with placeholders and generates a prompt for an AI to group text according to the template's structure.

{
	"template": "{ \"type\": \"<type>\", \"text\": \"<text>\" }"
}

The tool analyzes the template, extracts placeholder keys, and returns a prompt that guides the AI to extract information in a key-value format.

2. Text to JSON (text-to-json)

This tool takes the grouped text output from the previous step and converts it into a structured JSON object based on the original template.

{
	"template": "{ \"type\": \"<type>\", \"text\": \"<text>\" }",
	"text": "type: pen\ntext: This is a blue pen"
}

It extracts key-value pairs from the text and structures them according to the template.

Example Workflow

1. Define a JSON template with placeholders:

   {
   	"item": {
   		"name": "<name>",
   		"price": "<price>",
   		"description": "<description>"
   	}
   }
   

2. Use group-text-by-json to create a prompt for AI:

- The tool identifies placeholder keys: name, price, description
- Generates a prompt instructing the AI to group information by these keys

3. Send the prompt to an AI model and receive grouped text:

   name: Blue Pen
   price: $2.99
   description: A smooth-writing ballpoint pen with blue ink
   

4. Use text-to-json to convert the grouped text to JSON:
- Result:

   {

   	"item": {

   		"name": "Blue Pen",

   		"price": "$2.99",

   		"description": "A smooth-writing ballpoint pen with blue ink"

   	}

   }

   

Template Format

Templates can include placeholders anywhere within a valid JSON structure:

- Use angle brackets to define placeholders: <name>, <type>, <price>, etc.
- The template must be a valid JSON string
- Placeholders can be at any level of nesting
- Supports complex nested structures

Example template with nested placeholders:

{
	"product": {
		"details": {
			"name": "<name>",
			"category": "<category>"
		},
		"pricing": {
			"amount": "<price>",
			"currency": "USD"
		}
	},
	"metadata": {
		"timestamp": "2023-09-01T12:00:00Z"
	}
}

Implementation Details

The server works by:

1. Analyzing JSON templates to extract placeholder keys
2. Generating prompts that guide AI models to extract information by these keys
3. Parsing AI-generated text to extract key-value pairs
4. Reconstructing JSON objects based on the original template structure

Development

Prerequisites

- Node.js v18 or higher
- npm or yarn

Build and Run

```bash