tars

A personal search engine CLI that stores, crawls, and searches links using PostgreSQL with three search modes: BM25 keyword search, vector semantic search, and hybrid search combining both using Reciprocal Rank Fusion (RRF).

Features

• Link Management: Add, list, remove, and organize URLs
• Web Crawling: Extract titles, descriptions, and content from pages using Playwright
• BM25 Full-Text Search: Fast keyword matching with pg_textsearch
• Semantic Vector Search: Find conceptually similar content using OpenAI embeddings via pgvector
• Hybrid Search: Combine keyword and semantic search with RRF for best results
• Web Interface: Browser-based UI for searching and managing links
• MCP Server: Expose search as tools for LLM integration (Claude, etc.)
• Search Caching: Automatic caching of hybrid search results for performance

Prerequisites

• Python 3.12+
• uv (Python package manager)
• PostgreSQL with extensions:
  • pg_textsearch (BM25 search)
  • pgvector (vector similarity)
  • pgai (AI embeddings)

Database: Use TigerData (free tier available) which includes all required extensions pre-installed with managed OpenAI API keys for embeddings.

Installation

1. Clone and Install

git clone <repo-url>
cd search-engine

# Install globally as a uv tool
uv tool install -e .

# Or run without installing
uv run tars --help

2. Install Playwright Browser

playwright install chromium

3. Configure Database

Create a free database on TigerData, then add your connection string to a .env file:

# Option A: Single connection string
DATABASE_URL=postgresql://user:password@host:5432/dbname

# Option B: Individual variables
PGHOST=localhost
PGPORT=5432
PGDATABASE=tars
PGUSER=postgres
PGPASSWORD=secret

4. Initialize Database Schema

tars db init

This creates:

• links table with full-text search columns
• BM25 index for keyword search
• Search cache table for hybrid search results

5. Set Up Vector Search (Optional but Recommended)

# Add embedding column and HNSW index
tars db vector init

# Generate embeddings for existing links
tars db vector embed

Quick Start

# Add some links
tars add https://docs.python.org
tars add https://react.dev/learn
tars add https://www.postgresql.org/docs/

# Crawl to extract content
tars crawl

# Search (hybrid by default)
tars search "python web development"

# View all links
tars list

CLI Commands

Link Management

tars add <url>              # Add a new link
tars list                   # List all stored links (paginated)
tars list -n 20 -p 2        # Page 2 with 20 results per page
tars remove <url>           # Remove by URL
tars remove "*.example.com" # Remove by glob pattern
tars update <url>           # Update timestamp for a link
tars clean-list             # Remove duplicate links (CSV mode only)

Search Commands

# Hybrid search (BM25 + vector with RRF) - recommended
tars search "<query>"
tars search "machine learning" --keyword-weight 0.7 --vector-weight 0.3
tars search "python" --min-score 0.01 -n 20

# BM25 keyword search only
tars text_search "<query>"
tars text_search "postgresql tutorial" -n 10 -p 1

# Vector semantic search only
tars vector "<query>"
tars vector "how to build web apps" -n 10

Web Crawling

tars crawl                  # Crawl uncrawled links (default)
tars crawl <url>            # Crawl a specific URL
tars crawl --all            # Re-crawl all links
tars crawl --missing        # Only crawl links never crawled
tars crawl --old 7          # Crawl links not crawled in last 7 days

Database Management

tars db init                # Initialize database schema
tars db migrate             # Import links from CSV to database
tars db status              # Show database connection status

# Vector embedding management
tars db vector init         # Add embedding column and HNSW index
tars db vector embed        # Generate embeddings for all pending links
tars db vector embed -n 50  # Generate embeddings for 50 links
tars db vector status       # Show embedding status

Web Interface

tars web                    # Start web server at http://127.0.0.1:8000
tars web --port 3000        # Custom port
tars web --open             # Open browser automatically
tars web --reload           # Enable auto-reload for development

MCP Server (LLM Integration)

# Run as stdio server (for local Claude Code)
tars mcp

# Run as HTTP/SSE server (for remote connections)
tars mcp --sse --port 8000

Add to Claude Code's MCP config (~/.claude/claude_mcp_settings.json):

{
  "mcpServers": {
    "tars": {
      "command": "tars",
      "args": ["mcp"]
    }
  }
}

Search Modes Explained

BM25 Keyword Search (text_search)

• Uses pg_textsearch extension with BM25 ranking algorithm
• Best for exact keyword matching
• Fast and efficient for known terms

tars text_search "PostgreSQL performance tuning"

Vector Semantic Search (vector)

• Uses OpenAI text-embedding-3-small via pgai
• Finds conceptually similar content even without exact matches
• Great for natural language queries

tars vector "how do databases store data efficiently"

Hybrid Search (search)

• Combines BM25 and vector search using Reciprocal Rank Fusion (RRF)
• Best of both worlds: keyword precision + semantic understanding
• Adjustable weights to favor keywords or semantics

# Equal weights (default)
tars search "python machine learning"

# Favor keyword matches
tars search "exact error message" --keyword-weight 0.8 --vector-weight 0.2

# Favor semantic similarity
tars search "feeling anxious" --keyword-weight 0.3 --vector-weight 0.7

Architecture

src/tars/
├── __init__.py          # CLI entry point and argument parsing
├── db.py                # PostgreSQL operations (CRUD, search, embeddings)
├── crawl.py             # Web crawling with Playwright
├── mcp/                 # MCP server for LLM integration
│   ├── __init__.py
│   ├── server.py        # FastMCP server with tools
│   └── models.py        # Pydantic models for MCP responses
└── web/                 # Web interface
    ├── __init__.py
    ├── app.py           # FastAPI application
    ├── routes/          # API and page routes
    └── templates/       # Jinja2 HTML templates

Database Schema

CREATE TABLE links (
    id UUID PRIMARY KEY,
    url TEXT UNIQUE NOT NULL,
    title TEXT,
    description TEXT,
    content TEXT,
    notes TEXT,
    tags TEXT[],
    hidden BOOLEAN DEFAULT FALSE,
    added_at TIMESTAMPTZ,
    updated_at TIMESTAMPTZ,
    crawled_at TIMESTAMPTZ,
    http_status INTEGER,
    crawl_error TEXT,
    search_text TEXT GENERATED ALWAYS AS (...) STORED,
    embedding vector(1536)
);

Step-by-Step Setup Guide

Complete setup from scratch:

# 1. Install uv if not already installed
curl -LsSf https://astral.sh/uv/install.sh | sh

# 2. Clone the repository
git clone <repo-url>
cd search-engine

# 3. Install tars globally
uv tool install -e .

# 4. Install browser for crawling
playwright install chromium

# 5. Create database on TigerData (free tier available)
#    Sign up at: https://tsdb.co/jm-pgtextsearch
#    Create a service and copy the connection string

cat > .env << 'EOF'
DATABASE_URL=postgresql://user:password@host:5432/dbname
EOF

# 6. Initialize database
tars db init

# 7. Initialize vector search
tars db vector init

# 8. Add your first links
tars add https://docs.python.org
tars add https://react.dev
tars add https://www.postgresql.org

# 9. Crawl links to extract content
tars crawl

# 10. Generate embeddings for semantic search
tars db vector embed

# 11. Verify everything works
tars db status
tars db vector status

# 12. Search!
tars search "web development"
tars text_search "python"
tars vector "building modern applications"

# 13. (Optional) Start web interface
tars web --open

# 14. (Optional) Set up MCP for Claude Code
# Add to ~/.claude/claude_mcp_settings.json

Environment Variables

Variable	Description	Default
DATABASE_URL	PostgreSQL connection string	-
PGHOST	Database host	-
PGPORT	Database port	5432
PGDATABASE	Database name	-
PGUSER	Database user	-
PGPASSWORD	Database password	-
TARS_CACHE_TTL	Search cache TTL in seconds	3600

Dependencies

• rich - Terminal output formatting
• psycopg - PostgreSQL database access
• playwright - Web crawling
• python-dotenv - Environment configuration
• fastapi - Web interface API
• uvicorn - ASGI server
• jinja2 - HTML templating
• fastmcp - MCP server framework

License

MIT