Agent Skills: Codebase Map

Codebase Map

Generate a structural overview and dependency diagram of the current codebase.

Purpose

This skill produces a clear visual and textual representation of codebase structure, helping developers understand:

• How directories and modules are organised
• What each major component does
• How modules relate to and depend on each other

Prerequisites

• Git remote must exist (maps should be for projects with remotes)
• No requirement for clean working tree (read-only operation)

When to Use

Use this skill when you want to:

• Understand an unfamiliar codebase
• Document project architecture
• Onboard new team members
• Visualise module dependencies
• Get a high-level overview before diving into code

Workflow

Step 1: Verify Environment

Check we have a GitHub remote:

git remote -v

STOP if:

• No remote exists → "This skill requires a GitHub remote. Codebase maps are intended for projects with remotes."

Step 2: Explore the Codebase

Use the Task tool with subagent_type: "Explore" for thorough codebase exploration:

Tool: Task
Parameters:
  subagent_type: "Explore"
  description: "Explore codebase structure for mapping"
  prompt: |
    Explore this codebase to understand its structure and organisation.

    Identify:
    - Top-level directory structure and purpose of each directory
    - Entry points (main files, CLI entry points, server start files)
    - Key modules/packages and their responsibilities
    - Import relationships between modules
    - Configuration files and their purposes
    - Test structure and organisation
    - Build/deployment files

    For each significant directory:
    - What it contains
    - What purpose it serves
    - What depends on it / what it depends on

    Use thoroughness level: "very thorough"

    Return:
    1. Complete directory tree with annotations
    2. List of entry points
    3. Module dependency relationships
    4. Key configuration files

Step 3: Generate Structure Overview

Produce a hierarchical markdown overview of the codebase structure.

Format:

## Structure Overview

project-root/
├── src/                    # Main source code
│   ├── components/         # UI components
│   ├── services/           # Business logic and API calls
│   └── utils/              # Shared utilities
├── tests/                  # Test files mirroring src structure
├── config/                 # Configuration files
└── scripts/                # Build and deployment scripts

Guidelines for annotations:

• Keep descriptions short (3-8 words)
• Focus on purpose, not contents
• Only annotate significant directories
• Use consistent terminology

Step 4: Identify Key Files

List the most important files in the codebase with brief descriptions:

Format:

## Key Files

| File | Purpose |
|------|---------|
| `src/index.ts` | Application entry point |
| `src/config.ts` | Configuration loading and validation |
| `package.json` | Dependencies and scripts |

Include:

• Entry points
• Main configuration files
• Core modules that others depend on
• Files that define key abstractions

Step 5: Generate Dependency Diagram

Create a mermaid diagram showing module relationships.

Format:

graph TD
    A[Entry Point] --> B[Core Module]
    A --> C[Config]
    B --> D[Utils]
    B --> E[Services]
    E --> F[External APIs]

Guidelines:

• Show major modules, not individual files
• Group related functionality
• Indicate direction of dependency (arrow points from dependent to dependency)
• Keep diagram readable (10-20 nodes maximum)
• Use clear, short labels

Diagram types by project:

• Simple projects: Single graph TD showing module relationships
• Layered architectures: Show layers with subgraphs
• Microservices: Show service boundaries and communication

Step 6: Add Project-Specific Context

Include relevant context based on project type:

Python projects:

• Package structure (__init__.py locations)
• Virtual environment setup
• Entry points from pyproject.toml or setup.py

JavaScript/TypeScript projects:

• Module system (CommonJS vs ESM)
• Build output locations
• Package manager (npm, yarn, pnpm)

Multi-language projects:

• Language boundaries
• Inter-language communication
• Build coordination

Step 7: Compile Final Output

Combine all sections into the final output.

Output Format

# Codebase Map: [project-name]

## Summary

[2-3 sentences describing what this project is and its primary purpose]

## Structure Overview

[Hierarchical directory tree with annotations]

## Key Files

| File | Purpose |
|------|---------|
| ... | ... |

## Module Dependencies

[Mermaid diagram]

## Entry Points

- **Main**: `path/to/main` - Description
- **CLI**: `path/to/cli` - Description
- **Tests**: `path/to/tests` - Description

## Notes

[Any additional context: conventions, patterns, gotchas]

Guidelines

DO:

• Focus on structure and relationships, not implementation details
• Use consistent terminology throughout
• Keep annotations brief and informative
• Show what matters most (entry points, core modules)
• Tailor output to the project type
• Make the diagram readable (simplify if needed)

DON'T:

• List every single file
• Include generated or build output directories
• Add implementation details to annotations
• Create overly complex diagrams
• Speculate about purpose when unclear

Handling Different Project Types

Python Package

mypackage/
├── src/mypackage/      # Package source
│   ├── __init__.py     # Package initialisation
│   ├── core.py         # Core functionality
│   └── cli.py          # Command-line interface
├── tests/              # Test suite
├── pyproject.toml      # Project metadata and dependencies
└── README.md           # Documentation

JavaScript/Node.js

myproject/
├── src/                # Source files
│   ├── index.js        # Entry point
│   └── lib/            # Library code
├── dist/               # Build output (generated)
├── test/               # Tests
├── package.json        # Dependencies and scripts
└── tsconfig.json       # TypeScript config (if applicable)

Django Project

myproject/
├── myproject/          # Project settings
│   ├── settings.py     # Django settings
│   ├── urls.py         # URL routing
│   └── wsgi.py         # WSGI entry point
├── apps/               # Django applications
│   ├── users/          # User management
│   └── api/            # API endpoints
├── manage.py           # Django management script
└── requirements.txt    # Dependencies

Example Output

# Codebase Map: my-claude-skills

## Summary

A collection of Claude Code skills for automating development workflows. Skills handle tasks like ticket management, code review, and project setup.

## Structure Overview

my-claude-skills/
├── skills/                 # Individual skill definitions
│   ├── create-ticket/      # GitHub issue creation
│   ├── plan-ticket/        # Implementation planning
│   ├── implement-ticket/   # Ticket implementation
│   ├── review-pr/          # Pull request review
│   └── ...                 # Other skills
└── README.md               # Project documentation

## Key Files

| File | Purpose |
|------|---------|
| `skills/*/SKILL.md` | Skill definition and instructions |
| `README.md` | Usage documentation |

## Module Dependencies

```mermaid
graph TD
    CT[create-ticket] --> PT[plan-ticket]
    PT --> IT[implement-ticket]
    IT --> RP[review-pr]
    IT --> W[worktree]

Entry Points

• Skills: Individual SKILL.md files invoked via /skill-name

Notes

• Skills are symlinked to ~/.claude/skills/ for activation
• Each skill follows a standard YAML frontmatter format
• Skills can reference other skills in their workflows