modernize

Upgrade dependencies in brownfield applications while preserving spec-driven control.

Updated Aug 27, 2026
One-click install
npx skills add https://github.com/jschulte/stackshift --skill modernize
Or copy as Structured Prompt for Agent▼
Please help me install this Agent Skill.
Skill: modernize
Source: https://github.com/jschulte/stackshift/tree/main/skills/modernize
Command: npx skills add https://github.com/jschulte/stackshift --skill modernize

SYSTEM DOCUMENTATION & REQUIREMENTS

What problem does it solve?

Brownfield upgrades are risky and time-consuming. This Skill automates upgrading all dependencies and modernizing the application while preserving spec-driven control, reducing manual toil and preserving validated behavior.

Core Features & Use Cases

  • Spec-driven upgrade: Upgrades dependencies across the tech stack while keeping behavior aligned with existing specs.
  • Post-gear 6 workflow: Executes after Gear 6 when the modernize flag is enabled, coordinating audit, upgrade, testing, and spec synchronization.
  • Quality assurance & drift control: Re-validates test coverage and updates specs to reflect breaking changes, minimizing drift.

Quick Start

Run this Skill after Gear 6 with the modernize flag enabled to upgrade dependencies, refresh tests, and synchronize specs. The workflow includes pre-upgrade audit, dependency upgrades, breaking-change handling, and spec alignment.

Frequently Asked Questions about modernize

High-intent search queries and answers about installing and using this skill.

FAQPage Schema
How do I upgrade dependencies in a brownfield application while keeping tests aligned?▼

Spec-driven modernization upgrades all dependencies across your tech stack while preserving validated behavior through existing tests and specs. After Gear 6 completion with the modernize flag enabled, the Skill automatically detects package managers, audits current versions, executes stack-specific upgrade commands, runs tests, remediates breaking changes guided by specs, and re-validates 85%+ test coverage to ensure alignment.

What happens when dependency upgrades break my tests?▼

Breaking changes are identified during test execution and remediated using your specs as the source of truth. The Skill captures failures, applies spec-guided fixes, synchronizes specs to reflect necessary changes, and verifies that test coverage remains above 85% before completing the upgrade.

Can I upgrade dependencies across multiple tech stacks at once?▼

Yes. The Skill automatically detects and handles multiple package managers within your brownfield project, applying stack-specific upgrade commands to all supported stacks simultaneously while maintaining spec-driven control across the entire application.

What's required before running a dependency modernization?▼

Complete Gear 6 first and enable the modernize flag. Your project must have existing specs and tests in place; the Skill requires 85%+ test coverage and alignment with /speckit.analyze to ensure validated behavior is preserved during upgrades.

How does spec-driven upgrading reduce modernization risk?▼

Specs act as guardrails for acceptable behavior. The Skill uses them to guide breaking-change fixes, validate upgrades against documented requirements, and prevent drift between code and specification. Post-upgrade verification confirms test coverage and alignment with specs before completion.