migrate

Identify breaking changes between custom element manifests and generate migration reports.

46|4|Updated May 27, 2025

Search Tags:#git #breaking-changes #migrate #migration-guide #diff-analysis #custom-elements-manifest #version-diff

Ready to run

npx skills add https://github.com/bennypowers/cem --skill migrate-bennypowers

💬 Prompt for ChatGPT / Claude Chat▼

Please help me install this Agent Skill.
Skill: migrate
Source: https://github.com/bennypowers/cem/tree/main/extensions/claude-code/skills/migrate
Command: npx skills add https://github.com/bennypowers/cem --skill migrate-bennypowers

SYSTEM DOCUMENTATION & REQUIREMENTS

What problem does it solve?

Identify breaking changes between custom element manifests across versions and propose actionable migration steps, reducing upgrade risk.

Core Features & Use Cases

Phase 1: Identify Versions to Compare — choose two manifests or git refs and prepare context.
Phase 2: Diff Analysis — categorize changes into removing, changing, and adding elements, attributes, slots, events, and CSS hooks.
Phase 3: Impact Assessment — locate usage and provide migration recommendations.
Phase 4: Migration Report — generate a structured report with before/after examples and a recommended upgrade path.

Quick Start

Provide two manifest versions or git refs to run the migration analysis and generate a guided report.

Frequently Asked Questions about migrate

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

FAQPage Schema

How do I identify breaking changes between custom element manifest versions?▼

To identify breaking changes between custom element manifest versions, you can run a structured diff analysis that categorizes removed, changed, and added elements, attributes, slots, events, and CSS hooks, followed by an impact assessment to generate an actionable migration report.

What is the best way to generate a migration guide for web component upgrades?▼

The best way to generate a migration guide for web component upgrades is to compare two custom element manifests to assess impact, locate usage patterns, and produce a structured report with before/after examples and a recommended upgrade path.

Can I compare custom element manifests using git references instead of files?▼

Yes, you can compare custom element manifests using git references instead of local files, as the diff analysis supports git-based, file-based, and package-based comparisons to identify breaking changes across different versions.

How does custom element manifest diff analysis work for deprecation notes?▼

Custom element manifest diff analysis works for deprecation notes by categorizing removed or changed elements, attributes, slots, events, and CSS hooks between two versions, then locating existing usage to recommend formal migration steps.

What types of breaking changes are detected during a custom element migration?▼

During a custom element migration, the diff analysis detects breaking changes by categorizing removed, changed, and added elements, attributes, slots, events, and CSS hooks to provide a comprehensive impact assessment.