4.9 KiB

MCP Apps Merged Skill — Changelog

Merge Date: 2026-02-03

Added from Official ext-apps Skill

These sections/content were new from the official skill and did not exist in the custom skill:

Addition Location in Merged Doc
YAML frontmatter with trigger phrases Top of file
Framework selection table (Vue/Svelte/Preact/Solid) Quick Start Decision Tree
Project context section (adding to existing vs new) Quick Start Decision Tree
Full framework templates table (6 frameworks) Get Reference Code → Framework Templates
API Reference source files table Get Reference Code → API Reference
Additional advanced examples (video-resource, sheet-music, threejs, transcript, basic-host) Get Reference Code → Advanced Examples
npm install vs manual versions warning Required Packages + MUST DO table
tsx vs bun compatibility note Required Packages
ontoolinputpartial streaming section with use cases table and code patterns New section: Streaming Partial Input
Visibility-based resource management (IntersectionObserver) New section: Visibility-Based Resource Management
Fullscreen mode (requestDisplayMode()) with CSS patterns New section: Fullscreen Mode
Safe area insets handling (safeAreaInsets) New section: Safe Area Insets
sendLog for debug logging to host Client-Side + Debugging Checklist
Testing with basic-host example Testing section
Host styling split into Applying / Using subsections Host CSS Variables
line-height CSS variable example Host CSS Variables

Kept from Custom Battle-Tested Skill

Everything from the custom skill was preserved as the structural base:

Content Status
"What MCP Apps Actually Are" explanation Kept verbatim
"How The Data Flows" numbered diagram Kept verbatim
Quick Reference pattern Kept verbatim
Required Packages table Kept, enhanced with official notes
Project Structure tree Kept verbatim
Complete Server Template (annotated) Kept verbatim
Tool Registration quick reference Kept verbatim
Resource Registration snippet Kept verbatim
Tool Visibility Options Kept (merged — both had same content)
Server-Side Action Tools (view vs action) Kept verbatim
Complete HTML Template Kept verbatim
Complete UI Logic template Kept verbatim
Vanilla JS Full Lifecycle pattern Kept, enhanced with ontoolinputpartial + safe area
React Pattern Kept verbatim
Calling Server Tools snippet Kept verbatim
Updating Model Context snippet Kept verbatim
App Lifecycle Handlers table Kept, added ontoolinputpartial row
Host CSS Variables section Kept, merged with official's richer version
Build Configuration (vite, tsconfig, package.json) Kept verbatim
Module Scope Issue (critical gotcha) Kept verbatim
Drag-and-Drop Pattern (complete) Kept verbatim
Edit Modal Pattern (complete) Kept verbatim
CSS for Drag-and-Drop & Modals Kept verbatim
Key Lessons Learned (6 items) Kept verbatim
Data Handling Gotchas (array validation, escaping) Kept verbatim
MUST DO table Kept, added 4 rows from official
MUST NOT table Kept, added 3 rows from official
Host-Specific Notes (Goose, Claude Desktop) Kept verbatim
JSONRPC pipe testing commands Kept verbatim
Debugging Checklist Kept, added sendLog step
Common Errors table (10+ entries) Kept, added 2 rows from official
Summary: The Golden Path Kept, expanded with new steps
git clone reference code command Kept verbatim

Reorganization

Change Rationale
Moved "Get Reference Code" earlier (after Project Structure) Better flow — see examples before diving into implementation
Merged framework templates + advanced examples into one "Get Reference Code" section Eliminates duplicate reference code sections
Added dedicated sections for Streaming, Visibility, Fullscreen, Safe Areas These were inline in the official skill; standalone sections are more scannable
Split Host CSS Variables into "Applying" and "Using" subsections Clearer separation of setup vs usage
Enhanced MUST DO/MUST NOT tables with official skill's requirements Single authoritative rules table
Added sendLog to both client-side section and debugging checklist Available in two contexts where you'd need it
Expanded Golden Path summary from 6 to 10 steps Covers all new features (streaming, fullscreen, visibility, styling)

Deduplication

Only literally identical content was deduplicated:

  • Tool visibility options (identical in both) → kept once
  • git clone command (identical) → kept once
  • CSS variable examples (nearly identical) → merged into richer version with line-height
  • Handler registration order warning (same in both) → kept custom's more detailed version