Three post-publication corrections based on Anthropic's April 2026 documentation updates:
1. window.storage / persistent_storage: storage is now confirmed persistent
for published artifacts (Pro/Max/Team/Enterprise). Our v1.4 testing on
unpublished artifacts correctly showed session-scoped behavior. Updated
7 locations across Chapter 2, 9, 11, and Tool Card 37.
2. anthropic_api_in_artifacts: now officially documented as "AI-powered
artifacts." cache_creation/service_tier/inference_geo are standard API
response fields, not artifact-specific. Updated Chapter 9 and Tool Card 36.
3. MCP integration for artifacts: officially documented for Pro/Max/Team/
Enterprise plans. Updated Chapter 9.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Claude's Hidden Toolkit documents 28 undocumented internal tools across
Claude.ai's browser, desktop app, and mobile app interfaces. All parameter
schemas and response formats are empirically confirmed through cross-platform
testing.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>