mgrep Code Search

Overview

mgrep is a semantic search tool that enables natural language queries across code, text, PDFs, and images. It is particularly effective for exploring larger or complex codebases where traditional pattern matching falls short.

When to Use This Skill

Use mgrep when:

• The codebase contains more than 30 non-gitignored files
• There are nested directory structures
• Searching for concepts, features, or intent rather than exact strings
• Exploring an unfamiliar codebase
• Need to understand "where" or "how" something is implemented

Use traditional grep/ripgrep when:

• Searching for exact patterns or symbols
• Regex-based refactoring
• Tracing specific function or variable names

Quick Start

Indexing

Before searching, start the watcher to index the repository:

bunx @mixedbread/mgrep watch

The watch command indexes the repository and maintains synchronisation with file changes. It respects .gitignore and .mgrepignore patterns.

Searching

bunx @mixedbread/mgrep "your natural language query" [path]

Search Commands

Basic Search

bunx @mixedbread/mgrep "where is authentication configured?"
bunx @mixedbread/mgrep "how do we handle errors in API calls?" src/
bunx @mixedbread/mgrep "database connection setup" src/lib

Search Options

Option	Description
-m <count>	Maximum results (default: 10)
-c, --content	Display full result content
-a, --answer	Generate AI-powered synthesis of results
-s, --sync	Update index before searching
--no-rerank	Disable relevance optimisation

Examples with Options

# Get more results
bunx @mixedbread/mgrep -m 25 "user authentication flow"

# Show full content of matches
bunx @mixedbread/mgrep -c "error handling patterns"

# Get an AI-synthesised answer
bunx @mixedbread/mgrep -a "how does the caching layer work?"

# Sync index before searching
bunx @mixedbread/mgrep -s "payment processing" src/services

Workflow

1. Start watcher (once per session or when files change significantly):

   bunx @mixedbread/mgrep watch
   

2. Search semantically:

   bunx @mixedbread/mgrep "what you're looking for" [optional/path]
   

3. Refine as needed using path constraints or options:

   bunx @mixedbread/mgrep -m 20 -c "refined query" src/specific/directory
   

Environment Variables

Configure defaults via environment variables:

Variable	Purpose
MGREP_MAX_COUNT	Default result limit
MGREP_CONTENT	Enable content display (1/true)
MGREP_ANSWER	Enable AI synthesis (1/true)
MGREP_SYNC	Pre-search sync (1/true)

Important Notes

• Always use bunx @mixedbread/mgrep to run commands (not npm/npx or direct installation)
• Run bunx @mixedbread/mgrep watch before searching to ensure the index is current
• mgrep respects .gitignore patterns automatically
• Create .mgrepignore for additional exclusions