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
-
Start watcher (once per session or when files change significantly):
bunx @mixedbread/mgrep watch
-
Search semantically:
bunx @mixedbread/mgrep "what you're looking for" [optional/path]
-
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
