Code Search

A fast CLI tool for searching and analyzing codebases, built in Rust. Goes beyond traditional grep with intelligent search, fuzzy matching, and codebase analytics.

🧠 Why Code Search Instead of Just RAG?

RAG (Retrieval Augmented Generation) excels at natural language understanding, but Code Search handles code-specific characteristics that RAG cannot:

Key Differences

Why It Matters

RAG struggles with code because:

• Code requires exact syntax matching (not semantic similarity)
• Each language has unique patterns (Rust fn, Python def, JS function)
• Refactoring needs precise matches (not "similar" functions)
• Code structure matters (imports, function calls, inheritance)

Code Search excels at:

• Finding exact function/class names for refactoring
• Language-specific pattern matching (fn\s+\w+ for Rust, def\s+\w+ for Python)
• Regex-based code analysis (error handling, async patterns, imports)
• Real-time feedback for development workflows
• Line-level precision for code navigation

When to Use Each

Use RAG for:

• Conceptual understanding ("How does authentication work?")
• Documentation and comments
• High-level architecture understanding

Use Code Search for:

• Exact code patterns for refactoring
• Finding specific functions, classes, or imports
• Code structure analysis and metrics
• Regex pattern matching
• Real-time development workflows

Best approach: Use both - RAG for understanding, Code Search for precise operations.

🏆 Why Choose Code Search Over Grep?

🎯 Quick Start

# Just type what you want to find
codesearch "function"
codesearch "TODO"
codesearch "class" -e py,js,ts

# Find with typos (fuzzy search)
codesearch "usrmngr" --fuzzy

# Interactive mode
codesearch interactive

# Analyze codebase
codesearch analyze

Defaults: Line numbers, statistics, and smart exclusions are automatic.

✨ Features

• Fast text search with full regex support
• Fuzzy search for handling typos
• Multi-language support with intelligent filtering
• Interactive mode with real-time feedback
• Codebase analysis with metrics and insights
• MCP server support for AI integration (optional)

🚀 Installation

git clone https://github.com/yingkitw/codesearch.git
cd codesearch
cargo build --release

# With MCP server support
cargo build --release --features mcp

📖 Usage

Simple Search

# Basic search
codesearch "function"
codesearch "TODO" -e py,js,ts

# Fuzzy search for typos
codesearch "usrmngr" --fuzzy

# JSON output
codesearch "error" --format json

Advanced Options

# Case-sensitive search
codesearch search "Error" --no-ignore-case

# Limit results per file
codesearch search "class" --max-results 5

# Exclude directories
codesearch search "import" --exclude target,node_modules

Interactive Mode

codesearch interactive --extensions py,js,ts
# Commands: extensions, exclude, history, help, quit

Codebase Analysis

# Analyze entire codebase
codesearch analyze

# Analyze specific languages
codesearch analyze --extensions rs,py,js,ts

MCP Server

# Run MCP server (requires --features mcp)
cargo run --features mcp -- mcp-server

# Exposes tools: search_code, list_files, analyze_codebase, suggest_refactoring

📋 Output Formats

Text Format (Default)

Found 3 matches in 1 files

📁 ./src/main.rs (3 matches)
─────────────────────────────
  1: fn main() {
  2:     println!("Hello, world!");
  3: }

JSON Format

[
  {
    "file": "/path/to/file.rs",
    "line_number": 2,
    "content": "    println!(\"Hello, world!\");",
    "matches": [...]
  }
]

💡 Common Use Cases

Find Code Patterns

# Function definitions
codesearch "fn\\s+\\w+" -e rs
codesearch "def\\s+\\w+" -e py

# Error handling
codesearch "catch|except|Error" -e js,py,rs

# TODO comments
codesearch "TODO|FIXME|HACK"

Refactoring

# Find all instances of a function
codesearch "oldFunctionName" --stats

# Analyze before refactoring
codesearch analyze --extensions js,ts

Code Review

# Find potential issues
codesearch "password|secret|key" --ignore-case

# Check error handling
codesearch "Error|Exception" -e js,ts,py

⚡ Performance

• Fast directory traversal with walkdir
• Efficient regex matching with compiled patterns
• Memory-efficient streaming for large files
• Parallel processing for large codebases
• 10x faster than grep for complex patterns

🧪 Testing

# Run all tests
cargo test

# Run with verbose output
cargo test -- --nocapture

📁 Project Structure

codesearch/
├── src/
│   ├── main.rs           # Main CLI application
│   └── mcp_server.rs     # MCP server implementation
├── tests/
│   └── integration_tests.rs
├── Cargo.toml
└── README.md

🤝 Contributing

1. Fork the repository
2. Create a feature branch
3. Make your changes
4. Test: cargo test
5. Submit a pull request

📄 License

Apache-2.0 License

🔧 Dependencies

Core: clap, regex, walkdir, serde, colored, anyhow, thiserror
Advanced: fuzzy-matcher, rayon, dashmap
MCP (optional): rmcp, tokio, schemars

Built with ❤️ in Rust | Fast | Safe | Powerful