QA: Shared State (Read + Write) — Claude Agent SDK (Python)

Prerequisites

Demo is deployed and accessible at /demos/shared-state-read-write on the dashboard host
Agent backend is healthy (/api/health); ANTHROPIC_API_KEY is set on Railway; the FastAPI backend exposes POST /shared-state-read-write

Navigate to /demos/shared-state-read-write; verify the page renders within 3s with the left sidebar (preferences + notes cards) and the right-side CopilotChat pane
Verify data-testid="preferences-card" is visible with heading "Your preferences"
Verify data-testid="notes-card" is visible with heading "Agent notes" and empty-state data-testid="notes-empty" reading "No notes yet. Ask the agent to remember something."
Verify the chat input placeholder is "Chat with the agent..."
Verify all 3 suggestion pills are visible with verbatim titles: "Greet me", "Remember something", "Plan a weekend"
Send "Hello" and verify an assistant text response appears within 10s

Type "Atai" into data-testid="pref-name"; verify data-testid="pref-state-json" updates to include "name": "Atai"
Change data-testid="pref-tone" to formal; verify the JSON preview reflects "tone": "formal"
Change data-testid="pref-language" to Spanish; verify the JSON preview reflects "language": "Spanish"
Click the Cooking and Travel interest pills; verify both show the selected style (border #BEC2FF, bg #BEC2FF1A) and the JSON preview's interests array contains both entries
Send "What do you know about me?"; verify within 15s the assistant reply references the name "Atai", a formal tone, Spanish, and the Cooking/Travel interests (the Python backend's build_preferences_block injects these into the system prompt each turn)
Click the "Plan a weekend" suggestion; verify the reply is tailored to the selected interests

Click the "Remember something" suggestion (sends "Remember that I prefer morning meetings and that I don't eat dairy.")
Within 20s verify data-testid="notes-list" appears in the notes card and contains at least 2 data-testid="note-item" entries mentioning "morning meetings" and "dairy"
Verify data-testid="notes-empty" is no longer rendered
Send "Also remember I live in Berlin."; verify within 20s the notes list grows (previous notes preserved, new note added) — confirms the agent passes the FULL updated list per set_notes contract

With notes present, verify data-testid="notes-clear-button" is visible
Click the Clear button; verify the notes list disappears and data-testid="notes-empty" re-renders
Ask "What do you remember about me?"; verify the agent no longer cites the cleared notes (state was written back by the UI via agent.setState({ notes: [] }))

Change tone to playful and add the Music interest; send "Write me a one-line haiku greeting."; verify the reply is playful and references music
Send a follow-up "Do it again in French."; verify the reply remains playful, switches to French, and still acknowledges the music interest — confirms preferences persist across turns
Reload the page; verify preferences reset to defaults (tone: casual, language: English, empty interests, empty name) and notes reset to empty (state is per-session)

Attempt to send an empty message; verify it is a no-op (no user bubble, no assistant response)
Deselect all interests and clear the name; send "Who am I?"; verify the agent answers without crashing (the preferences block is skipped when nothing recognised is set)
Verify DevTools -> Console shows no uncaught errors during any flow above

Page loads within 3 seconds; assistant text response within 10 seconds for plain chat
Preferences writes are reflected in pref-state-json synchronously on change
Agent-authored notes appear in notes-card within 20 seconds of a "remember" prompt, and the full prior list is preserved on subsequent set_notes calls
Clear button round-trips UI -> agent state and the agent loses access to the cleared notes on the next turn
No UI layout breaks, no uncaught console errors