grep-app

name	grep-app
description	Code search across millions of public GitHub repositories via grep.app. Use before writing or planning code to find real-world usage of libraries, frameworks, APIs, algorithms, or syntax patterns. Prefer this over web search for code examples.

grep.app

Search real-world code examples from over a million public GitHub repositories. Powered by grep.app MCP. No API key required.

searchGitHub

Find real-world code examples by searching for literal code patterns (like grep), not keywords.

• query (required): literal code pattern (e.g. useState(, import React from, async function)
• language: array of language filters (e.g. Python, TypeScript, TSX, Java, Go, Rust, C#, YAML, Markdown)
• repo: filter by repository (e.g. facebook/react, vercel/) — partial names match
• path: filter by file path (e.g. src/components/Button.tsx, /route.ts) — partial paths match
• useRegexp: interpret query as regex (default: false). Prefix with (?s) for multiline
• matchCase: case-sensitive search (default: false)
• matchWholeWords: match whole words only (default: false)

Basic usage

uv run --script scripts/mcpcall.py searchGitHub query:"useState("
uv run --script scripts/mcpcall.py searchGitHub query:"getServerSession" --args '{"language": ["TypeScript", "TSX"]}'
uv run --script scripts/mcpcall.py searchGitHub query:"CORS(" matchCase:true --args '{"language": ["Python"]}'

Filter by repo or path

uv run --script scripts/mcpcall.py searchGitHub query:"createContext" repo:"facebook/react"
uv run --script scripts/mcpcall.py searchGitHub query:"export default" path:"/route.ts" --args '{"language": ["TypeScript"]}'

Regex patterns

uv run --script scripts/mcpcall.py searchGitHub query:"(?s)useEffect\\(\\(\\) => \\{.*removeEventListener" useRegexp:true
uv run --script scripts/mcpcall.py searchGitHub query:"(?s)try \\{.*await" useRegexp:true --args '{"language": ["TypeScript"]}'

Tips

• Search for actual code that appears in files, not keywords or questions
  • Good: useState(, import React from, async function
  • Bad: react tutorial, best practices, how to use
• Use (?s) prefix in regex to match across multiple lines
• Filter by language to narrow results to relevant file types
• Filter by repo with org prefix (e.g. vercel/) to search within an organization
• Combine matchCase:true with specific function names for precise matches