- **Artifact execution layer section** (Chapter 9) — documents Claude-inside-Claude architecture: `anthropic_api_in_artifacts` (authenticated API calls from artifacts without API key), `persistent_storage` (session-scoped `window.storage`), MCP endpoint access from React artifacts
- **MCP connector state** as an architectural variable (Chapter 2) — connecting/disconnecting Gmail or Google Calendar changes the always-loaded tool pool
- **Project context behavior** section — confirmed Projects do not change tool behavior
- **Ghost tools** section (Chapter 12) — `gmail_send_draft` and `gmail_modify_thread` exist in schema but are not deployed
- **iOS vs Android differences** — `user_location_v0` returns richer response on iOS (sub_locality, accuracy fields); `user_time_v0` timestamp format differs (no microseconds on iOS)
### Changed (Corrections)
- **`user_time_v0` and `user_location_v0`**: reclassified from deferred to **always-loaded** on mobile — MCP connector state is irrelevant (v1.3 error)
- **`memory_user_edits`**: limit corrected from 200 characters (server-enforced) to **500 characters** (client-side validation). The limit may vary by tier or build
- **`chart_display_v0`**: crash status downgraded from deterministic (100%) to **intermittent/state-dependent**. Tool is always deferred on mobile, not first-class
- **`tool_search` on browser**: corrected from "does not exist" to **conditionally available** when MCP connectors are active, returning tools with `Provider:tool_name` prefix
- **`window.storage`**: reframed from "persistent" to **session-scoped** — data is destroyed when session closes, does not persist across chats even within the same Project
- **`anthropic_api_in_artifacts`**: corrected from Desktop-only to working on **both Desktop and Browser** React artifacts (HTML artifacts blocked by CSP)
- **`web_fetch`**: corrected from 8 to **9 parameters** (added `html_extraction_method`)
- **`bash_tool`**: corrected from 1 to **2 parameters** (added required `description`)
- **`str_replace`**: corrected from 3 to **4 parameters** (added required `description`)
- **Calendar tools**: always-loaded when MCP Calendar connector active (not always deferred)
- **Platform matrix**: updated to reflect iOS as distinct surface with 5 additional Reminders tools
- **`visualize:show_widget` vs `chart_display_v0`**: documented as mutually exclusive by surface — `chart_display_v0` mobile only, `show_widget` desktop/browser only
### Removed
- Deterministic crash claim for `chart_display_v0`
- "tool_search absent on browser" claim
- 200-character server-enforced limit claim for `memory_user_edits`
- Platform-exclusive tools table showing which tools exist where
- Session instability warning (switching clients changes available tools)
- Fallback behavior documentation for each platform gap
- Settings & Connectors reference integrated into appendix
- 9 new figure placeholders (fig_14 through fig_22)
### Changed
- **Chapter 10 (Discovery Log)**: added mobile-only environment note — the discovery log was produced on mobile and is not reproducible on browser or desktop
- **Chapter 2 (Architecture)**: rewritten to reflect three platform configurations instead of a single binary always-loaded/deferred model
- **Card 5 (message_compose_v1)**: corrected primary button to "Send via Gmail", documented dropdown with "Open in Mail", added no-recipient-field note