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QA: Frontend Tools (Async) — LangGraph (Python)

showcase/integrations/langgraph-python/qa/frontend-tools-async.md

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QA: Frontend Tools (Async) — LangGraph (Python)

Prerequisites

  • Demo is deployed and accessible at /demos/frontend-tools-async on the dashboard host
  • Agent backend is healthy (/api/copilotkit GET returns langgraph_status: "reachable"); OPENAI_API_KEY is set; LANGGRAPH_DEPLOYMENT_URL points at a deployment exposing the frontend_tools_async graph (registered under agent name frontend-tools-async)
  • Backend frontend_tools_async.py registers NO server-side tools; the frontend registers exactly ONE tool via useFrontendTool: query_notes (parameter: keyword: string)
  • The async handler sleeps 500ms (simulated client-side DB latency) then filters an in-memory NOTES_DB of 7 hard-coded notes, returning up to 5 matches against title, excerpt, or tags (case-insensitive). The tool has a custom render that mounts NotesCard

Test Steps

1. Basic Functionality

  • Navigate to /demos/frontend-tools-async; verify the CopilotChat panel renders centered (max width 4xl, rounded-2xl corners) within 3s
  • Verify the input placeholder "Type a message" is visible
  • Send "Hello"; verify the agent responds with plain text within 10s and does NOT invoke query_notes

2. Feature-Specific Checks

Suggestion Pills

  • Verify all three suggestion pills are visible with verbatim titles:
    • "Find project-planning notes"
    • "Search for 'auth'"
    • "What do I have about reading?"
  • Click "Find project-planning notes"; verify the prompt "Find my notes about project planning." is sent

query_notes — Async Handler Loading State

  • After triggering the query_notes flow (via pill or typing "Find my notes about planning"), verify within 10s a data-testid="notes-card" element renders in the transcript
  • While the handler's 500ms sleep is in flight (tool status ≠ complete), verify the card's header shows:
    • An uppercase "Notes DB" label
    • A heading data-testid="notes-keyword" reading Matching "<keyword>" where <keyword> is the agent's chosen search term (e.g. planning, project planning)
    • The subtext "Querying local notes DB..."
    • A "..." placeholder glyph (not the 📓 book emoji)

query_notes — Resolved State (Simulated DB Query)

  • After the 500ms sleep resolves, verify the card's loading state ends within 2s:
    • The placeholder glyph flips from "..." to "📓"
    • The subtext shows "N match" or "N matches" (singular when N=1)
    • A data-testid="notes-list" <ul> renders (assuming N > 0)
  • Verify the list contains between 1 and 5 <li> entries, each with data-testid="note-<id>" (IDs from n1n7)
  • For the prompt "Find my notes about project planning", verify the returned notes include at least note-n1 (Q2 project planning kickoff) and note-n5 (Project planning retrospective notes)
  • Verify each note row renders title (bold), excerpt (grey small text), and tag pills (uppercase, rounded-full)

Round-Trip — Agent Consumes Async Handler Result

  • After the card renders, verify the agent emits a follow-up assistant text message within 10s summarizing the matches
  • Verify the summary references at least one note title or tag from the notes-card (confirms the agent awaited the async handler's resolved value, not just fired-and-forgot)
  • Ask a follow-up like "Which of those is about onboarding?"; verify the agent references note n1's excerpt ("new onboarding flow") — proving the previous tool result is retained in context

Zero-Match Branch — Notes Card Empty State

  • Send "Search my notes for xyzzy-nonsense-keyword"
  • Verify a data-testid="notes-card" renders with heading Matching "xyzzy-nonsense-keyword" (or close variant)
  • Verify the card shows italic grey text "No notes matched." (no notes-list element)
  • Verify the agent's follow-up text says no matches were found and offers to try a different keyword

3. Error Handling

  • Send an empty message; verify it is a no-op (no notes-card, no user bubble)
  • Send a ~500-character unrelated prompt; verify the agent responds without calling query_notes
  • Trigger two query_notes invocations in quick succession (e.g. "Find auth notes" then immediately "Find reading notes"); verify both resolve independently and render two separate notes-card instances in the transcript
  • Open DevTools → Console; verify no uncaught errors, no Zod parse failures, no unresolved-Promise warnings

Expected Results

  • Chat loads within 3 seconds; notes-card loading state appears within 10 seconds of prompt
  • Async handler's 500ms sleep is observable — the loading state ("Querying local notes DB...") is visible before resolution
  • After resolution, the notes-list renders with the correct subset of NOTES_DB matching the keyword
  • Agent's follow-up reply demonstrably uses the resolved notes array (round-trip verified)
  • Zero-match prompts render the empty-state branch, not a broken card
  • No uncaught console errors; handler Promise always resolves; no layout breaks