What is the main benefit of using the Modernize skill?

It automates the complex process of upgrading outdated dependencies while using your project's specifications as a safety net to ensure no functional regressions occur.

When should I run the Modernize skill?

It is designed to run on brownfield projects after initial specifications and test coverage have been established, typically after Gear 6 of the StackShift workflow.

What test coverage does the skill aim for?

The skill targets a minimum of 85% test coverage across all modules to ensure the modernized codebase remains stable and maintainable.

Which programming languages does this skill support?

It supports major ecosystems including Node.js (npm, yarn, pnpm), Python (pip), Go (go mod), and Rust (cargo).

Does it automatically fix breaking changes?

Yes, it identifies breaking changes through test failures and compilation errors, then uses your project's specs to guide iterative code fixes.

StackShift Modernize

Name: StackShift Modernize
Author: jschulte

byjschulte

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Security & Testing

Upgrades legacy dependencies and modernizes brownfield applications while maintaining rigorous spec-driven control and high test coverage.

About

StackShift Modernize is a specialized Claude Code skill designed to transform legacy brownfield applications into modern, spec-driven codebases. It systematically identifies outdated dependencies, executes major version upgrades across various tech stacks including Node.js, Python, Go, and Rust, and iteratively fixes breaking changes using existing specifications as a safety net. By enforcing an 85% test coverage threshold and synchronizing implementation behavior with feature specs, it ensures that your application stays secure and performant without losing functional integrity during the upgrade process.

Key Features

Automated breaking change detection and spec-guided fixes
Spec-to-implementation synchronization and drift analysis
Multi-stack dependency upgrading for Node.js, Python, Go, and Rust
Pre-upgrade auditing and baseline state documentation
1 GitHub stars
Enforced 85%+ test coverage threshold for all modules

Use Cases

Upgrading a legacy Node.js application to latest major versions and security patches.
Migrating a Python project to modern, audited dependency versions with updated requirements.
Modernizing brownfield codebases while ensuring 100% alignment with technical specifications.

About

Key Features

Automated breaking change detection and spec-guided fixes
Spec-to-implementation synchronization and drift analysis
Multi-stack dependency upgrading for Node.js, Python, Go, and Rust
Pre-upgrade auditing and baseline state documentation
1 GitHub stars
Enforced 85%+ test coverage threshold for all modules

Use Cases

Upgrading a legacy Node.js application to latest major versions and security patches.
Migrating a Python project to modern, audited dependency versions with updated requirements.
Modernizing brownfield codebases while ensuring 100% alignment with technical specifications.