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name: mapping-codebases description: Generate navigable code maps for unfamiliar codebases. Use when exploring a new codebase, needing to understand project structure, or before diving into code modifications. Extracts exports/imports via AST (tree-sitter) to create _MAP.md files per directory. Triggers on "map this codebase", "understand this project structure", "generate code map", or when starting work on an unfamiliar repository.

Mapping Codebases

Generate _MAP.md files that provide a hierarchical view of code structure without reading every file.

Quick Start

# Install dependencies (once per session)
uv pip install tree-sitter==0.21.3 tree-sitter-languages==1.10.2

# Generate maps for a codebase
python scripts/codemap.py /path/to/repo

What It Produces

Per-directory _MAP.md files listing:

• Directory statistics (file count, subdirectory count)
• Subdirectories (with links to their maps)
• Files with exports and imports
• Counts when lists are truncated (e.g., "exports (23)" when showing 8 of 23)

Example output:

# auth/
*Files: 3 | Subdirectories: 1*

## Subdirectories
- [middleware/](./middleware/_MAP.md)

## Files
- **jwt.go** — exports: `Claims, ValidateToken` — imports: `context, jwt`
- **handlers.py** — exports (12): `login, logout, refresh_token`... — imports (8): `flask, .models`...

Supported Languages

Python, JavaScript, TypeScript, TSX, Go, Rust, Ruby, Java.

Commands

python scripts/codemap.py /path/to/repo                    # Generate maps
python scripts/codemap.py /path/to/repo --skip locale,tests # Skip specific directories
python scripts/codemap.py /path/to/repo --clean             # Remove all _MAP.md
python scripts/codemap.py /path/to/repo -n                  # Dry run (preview)

Skip Patterns

Use --skip to exclude directories that add noise without value:

# Common patterns
--skip locale,migrations,tests              # Django projects
--skip locales,__snapshots__,coverage       # JavaScript projects
--skip target,docs                          # Rust projects

Default skip patterns: .git, node_modules, __pycache__, .venv, venv, dist, build, .next

Workflow Integration

1. Run codemap.py on the target repo first
2. Read _MAP.md at repo root for overview (high-level structure)
3. Navigate to relevant subdirectory maps as needed (drill down)
4. Read actual source files only when necessary

Maps use hierarchical disclosure - you only load what you need. Even massive codebases (1000+ files) stay navigable because each map remains focused on its directory.

Features

Directory Statistics: Each map header shows file and subdirectory counts, helping you quickly assess scope.

Export/Import Counts: When truncated, shows total count (e.g., "exports (23)") so you know how much detail exists without cluttering the view.

Hierarchical Navigation: Links between maps let you traverse the codebase structure naturally without overwhelming context windows.

Skip Patterns: Exclude noise directories (locales with 100+ language subdirs, test snapshots, generated code) to focus maps on actual source code.

Git Hook (Optional)

For repos where maps should stay fresh:

# .git/hooks/pre-commit
#!/bin/sh
python /path/to/codemap.py . >/dev/null
git add '*/_MAP.md'

Limitations

• Extracts structural info only (exports/imports), not semantic descriptions
• Skips: .git, node_modules, __pycache__, venv, dist, build (plus user-specified patterns)
• Private symbols (Python _prefix) excluded from exports