APLCart MCP Server

A Model Context Protocol (MCP) server that exposes the APLCart idiom collection with semantic search capabilities. APLCart is a searchable collection of APL expressions with descriptions.

Features

• Find APL expressions by exact syntax match
• Search across syntax, descriptions, and keywords
• Get keywords for specific APL expressions
• Natural language queries using OpenAI embeddings

About APLCart

APLCart is a searchable collection of APL idioms and expressions maintained at https://aplcart.info/

Installation

Prerequisites

• Python 3.11 or higher
• OpenAI API key (for semantic search functionality)

Using uv

# Install uv if you haven't already
curl -LsSf https://astral.sh/uv/install.sh | sh

# Clone the repository
git clone <repository-url>
cd ac-mcp

# Install dependencies
uv sync

Setup

Convert APLCart Data

First, fetch and convert the APLCart TSV data to JSONL format:

# Using uv
uv run python aplcart2json.py

# Or with activated venv
python aplcart2json.py

# Optional: Generate SQLite database for faster searches
python aplcart2json.py --db

Generate Embeddings (Optional; for Semantic Search)

To enable semantic search functionality:

# Set your OpenAI API key
export OPENAI_API_KEY='your-api-key-here'

# Generate embeddings
uv run python generate_embeddings.py

# Or with activated venv
python generate_embeddings.py

This creates:

• aplcart.index - FAISS index file containing embeddings
• aplcart_metadata.pkl - Metadata for semantic search results

Usage

Running the MCP Server

# Basic usage
uv run python aplcart_mcp_semantic.py

# With SQLite database backend
APLCART_USE_DB=1 uv run python aplcart_mcp_semantic.py

Using with Claude Code

The project includes a .mcp.json.template file that automatically configures the MCP server. Save that as .mcp.json, update it with your details, and run /mcp in Claude Code to see available servers.

You can also manually add the server:

claude mcp add aplcart "uv run python aplcart_mcp_semantic.py"

Using with Claude Desktop

Add this to your Claude Desktop configuration file:

• macOS: ~/Library/Application Support/Claude/claude_desktop_config.json
• Windows: %APPDATA%\Claude\claude_desktop_config.json
• Linux: ~/.config/claude/claude_desktop_config.json

{
  "mcpServers": {
    "aplcart": {
      "command": "uv",
      "args": [
        "run",
        "--directory",
        "YOUR/PATH/HERE/ac-mcp",
        "python",
        "aplcart_mcp_semantic.py"
      ],
      "env": {
        "APLCART_USE_DB": "1",
        "OPENAI_API_KEY": "${OPENAI_API_KEY}"
      }
    }
  }
}

Then restart Claude Desktop to load the MCP server.

Available MCP Tools

• lookup-syntax - Exact match on APL syntax

  Copy

  Example: lookup-syntax "⍳10"

• search - Substring search across syntax, description, and keywords

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  Example: search "matrix" limit=10

• keywords-for - Get keywords for a specific syntax

  Copy

  Example: keywords-for "∘.≤⍨∘⍳"

• semantic-search - Natural language search using embeddings

  Copy

  Example: semantic-search "how to split a string on a separator"

Standalone Search Tool

You can also use the semantic search functionality directly:

# Interactive mode
uv run python search_embeddings.py

# Single query
uv run python search_embeddings.py "find the largest number"

# JSON output
uv run python search_embeddings.py "reverse an array" --json

# More results
uv run python search_embeddings.py "matrix operations" -k 10

Interactive mode commands:

• Type your query and press Enter to search
• Type quit, exit, or q to exit (or Ctrl+D or Ctrl+C)

Configuration

Environment Variables

• OPENAI_API_KEY - Required for semantic search functionality
• APLCART_USE_DB - Set to 1, true, or yes to use SQLite database backend

File Structure

ac-mcp/
├── aplcart.jsonl           # Converted APLCart data (run aplcart2json.py to generate)
├── aplcart.db              # SQLite database (optional)
├── aplcart.index           # FAISS embeddings index (run generate_embeddings.py to generate)
├── aplcart_metadata.pkl    # Metadata for semantic search (run generate_embeddings.py to generate)
├── aplcart2json.py         # Converter script
├── generate_embeddings.py  # Embedding generator
├── aplcart_mcp_semantic.py # MCP server with semantic search
├── search_embeddings.py    # Standalone search tool
└── pyproject.toml          # Project dependencies

License

This project is licensed under the MIT License - see the LICENSE file for details.

Note: The APLCart data itself is subject to its own licensing terms.