Python Dependency Mapper

A fast Rust CLI tool for analyzing Python codebases and mapping module dependencies. Designed for both human engineers and AI coding assistants to understand, maintain, and refactor large Python projects.

Features

Core Analysis Commands

• Impact Analysis - Identify all modules that depend on a specific module (blast radius)
• Dependencies - Show all dependencies of a specific module
• Circular Dependencies - Detect and report dependency cycles
• Dead Code Detection - Find orphaned modules with no dependents
• External Dependencies - Audit external package usage across the codebase with manual package declarations
• Pressure Points - Identify modules with the highest number of dependents
• Metrics - Display overall codebase health indicators

AI Agent Integration

• Smart Context Selection - Curated file lists for AI agents
• Risk Assessment - Pre-change complexity analysis
• Dependency Validation - Prevent circular dependencies
• Parallel Work Identification - Enable multi-agent workflows

Output Formats

• Human-readable text (default)
• JSON for programmatic processing
• CSV for spreadsheet analysis
• DOT/Graphviz for visualization
• Agent-optimized Markdown
• Cursor IDE context format

Installation

Prerequisites

• Rust 1.70+ (uses Rust 2024 edition)
• Python 3.10+ codebase to analyze

Build from Source

git clone <repository-url>
cd pydep-mapper-rust

cargo build --release

Install with cargo

cargo install pydep-mapper

Quick Start

The commands should be launched at the root of your python project, where your pyproject.toml is located.

# Check what modules depend on a specific module (blast radius analysis)

pydep-mapper impact src.payments.processor


# Check what modules a specific module depends on

pydep-mapper dependencies src.payments.processor


# Find all circular dependencies

pydep-mapper cycles


# Analyze external dependencies (includes packages from .used-externals.txt if present)

pydep-mapper external


# Show modules with most dependencies (pressure points), can be combined with grep or head

pydep-mapper pressure


# General analysis of a Python codebase

pydep-mapper analyze

Usage Examples

Impact Analysis

# See what breaks if you change this module

pydep-mapper impact src.payments.processor


# Output:

# Modules depending on 'src.payments.processor':

# - src.api.billing (Imports)

# - src.services.subscription (Imports)

# - tests.test_payments (Imports)

# Total: 3 modules affected

Dependencies Inspection

# See what a module depends on

pydep-mapper dependencies src.payments.processor


# Output:

# Dependencies of 'src.payments.processor':

# - stripe (External - Imports)

# - src.models.payment (Internal - Imports)

# - src.utils.validation (Internal - Imports)

# Total: 3 dependencies (1 external, 2 internal)

External Dependencies with Manual Declarations

# Analyze external dependencies

pydep-mapper external


# Output includes both code-detected and manually declared packages:

# External Dependencies Analysis:

# 

# === Summary ===

# Total external packages used: 127

# Manually declared externals: 10

Manual Package Declarations: Create a .used-externals.txt file in the same directory as your pyproject.toml to declare additional packages that should be considered "used" even if not directly imported in code:

# .used-externals.txt
# Build tools
setuptools
wheel

# Runtime dependencies not directly imported
redis  # Used via config
docker # Used in deployment

# Development tools
ruff
mypy  # Type checker

Features of .used-externals.txt:

• One package name per line
• Comments with # (full-line or inline)
• Automatic normalization to PyPI naming conventions
• Merges with code-detected packages
• Optional - works silently when file doesn't exist

Architecture Health

# Check for circular dependencies

pydep-mapper cycles


# Get overall metrics (coming soon™)

pydep-mapper metrics


# Find potential dead code (coming soon™)

pydep-mapper orphans

AI Agent Integration (coming soon™)

Parser Features

• Static Analysis: Uses rustpython-parser for AST-based parsing
• Import Styles: Supports all Python import patterns:
  • import module
  • from module import name
  • from module import *
  • Nested paths and aliases
• Original Names: Extracts original module names (ignores aliases like import numpy as np)

Graph Model

The tool builds a dependency graph with three relationship types:

• Imports: Direct import relationships
• Contains: Package/module containment
• IncludedIn: Reverse containment relationships

Dependencies

• rustpython-parser - Python AST parsing
• petgraph - Graph data structures and algorithms
• clap - Command line interface
• walkdir - File system traversal
• anyhow - Error handling
• serde - Serialization for JSON output
• indicatif - Progress bars

Development

Building

cargo build

cargo run -- analyze /path/to/project

Testing

cargo test

Code Quality

cargo clippy

cargo fmt

Use Cases

For Human Engineers

• Refactoring: Understand blast radius before making changes
• Architecture Review: Identify circular dependencies and coupling issues
• Code Cleanup: Find dead code and unused modules
• Security Audits: Track external dependency usage

For AI Coding Assistants

• Context Selection: Get relevant files for code understanding
• Risk Assessment: Evaluate change complexity before implementation
• Dependency Validation: Prevent architectural violations
• Parallel Work: Enable multiple agents to work independently

Target Scope

• Codebase Size: Optimized for Python projects up to ~100k lines
• Analysis Type: Static imports only (excludes dynamic imports)
• Python Version: Targets Python 3.10+ codebases

Contributing

1. Fork the repository
2. Create a feature branch
3. Make your changes following the project's principles:
   • Simplicity first (YAGNI)
   • Prefer functions over complex structures
   • Eliminate data redundancy
   • Self-documenting code
4. Run tests and quality checks
5. Submit a pull request