Python Api Consistency Validator

---
name: python-api-consistency-validator
description: Validate API consistency between two versions of Python libraries. Use when you need to compare API behavior, signatures, and exceptions between library versions to identify breaking changes, incompatible modifications, and behavior differences. The skill performs static analysis of Python code, compares function signatures, class definitions, parameter types, return types, and generates a detailed JSON report with breaking changes, warnings, and migration guidance. Supports Python libraries and packages.
---

# Python API Consistency Validator

## Overview

This skill validates API consistency between two versions of Python libraries by comparing signatures, behavior, and exceptions. It identifies breaking changes, incompatible modifications, and provides detailed reports to guide safe API migration or upgrade.

## Quick Start

```bash
# Compare two versions of a Python library
python scripts/validate.py /path/to/old_version /path/to/new_version

# Specify output file
python scripts/validate.py old_lib/ new_lib/ --output report.json
```

## What Gets Validated

1. **Function Signatures** - Parameters, return types, decorators
2. **Class Definitions** - Methods, inheritance, attributes
3. **Parameter Changes** - Added, removed, or modified parameters
4. **Return Type Changes** - Modified return types
5. **Removed APIs** - Deleted functions, classes, or methods

## Validation Report

The tool generates a JSON report with:

- **Breaking Changes**: API removals, incompatible modifications
- **Warnings**: Type changes, signature modifications
- **Info**: New additions, non-breaking changes
- **Summary**: Total issues by severity

Example report:
```json
{
  "summary": {
    "breaking_changes": 3,
    "warnings": 5,
    "info": 2
  },
  "breaking_changes": [
    {
      "type": "function_removed",
      "name": "deprecated_func",
      "severity": "breaking",
      "message": "Function 'deprecated_func' was removed"
    }
  ]
}
```

## Usage

```bash
python scripts/validate.py <old_version_path> <new_version_path> [--output <report.json>]
```

The validator exits with code 1 if breaking changes are found, 0 otherwise.

## Tips

- Run validation before upgrading dependencies
- Review breaking changes carefully
- Check warnings for potential issues
- Use in CI/CD pipelines to catch API changes
- Compare against semantic versioning expectations