popiart-node-canvas/.planning/phases/31-workflow-proposal-system/31-02-SUMMARY.md

phase: 31-workflow-proposal-system plan: 02 subsystem: api tags: [vercel-ai-sdk, streaming, gemini, chat, ai-sdk-google] # Dependency graph requires: - phase: 31-01 provides: WorkflowProposal types, domain prompts provides: - Streaming /api/chat endpoint - Chat types (ChatMessage, ChatRole, ConversationState) - Vercel AI SDK integration with Gemini affects: [31-03-chat-ui, workflow-planning] # Tech tracking tech-stack: added: [ai@6.0.49, @ai-sdk/google@3.0.13] patterns: [createGoogleGenerativeAI, streamText, toTextStreamResponse] key-files: created: - src/types/chat.ts - src/app/api/chat/route.ts modified: - src/types/index.ts - package.json key-decisions: - "Use createGoogleGenerativeAI factory for custom API key injection" - "toTextStreamResponse for AI SDK v6 streaming (not toDataStreamResponse)" - "System prompt contains full Node Banana domain expertise for conversational planning" patterns-established: - "Vercel AI SDK streaming pattern: createGoogleGenerativeAI → streamText → toTextStreamResponse" issues-created: [] # Metrics duration: 2min completed: 2026-01-26

Phase 31 Plan 02: Chat Infrastructure Summary

Streaming chat endpoint with Vercel AI SDK, Gemini integration, and conversational workflow planning assistant

Performance

• Duration: 2 min
• Started: 2026-01-26T09:37:57Z
• Completed: 2026-01-26T09:40:07Z
• Tasks: 4
• Files modified: 4

Accomplishments

• Installed Vercel AI SDK packages (ai, @ai-sdk/google)
• Created chat types for conversation state management
• Built streaming /api/chat endpoint with domain expertise
• Exported chat types from central type index

Task Commits

Each task was committed atomically:

1. Task 1: Install Vercel AI SDK packages - 744e0a7 (chore)
2. Task 2: Create chat types - b263c03 (feat)
3. Task 3: Create streaming chat endpoint - 727e54d (feat)
4. Task 4: Update type exports - e558777 (feat)

Files Created/Modified

• src/types/chat.ts - ChatMessage, ChatRole, ConversationState, ChatRequest types
• src/app/api/chat/route.ts - Streaming POST endpoint with Node Banana system prompt
• src/types/index.ts - Added chat types re-export
• package.json - Added ai and @ai-sdk/google dependencies

Decisions Made

• Used createGoogleGenerativeAI factory instead of default google export to inject API key from GEMINI_API_KEY env var
• Used toTextStreamResponse() which is the correct method in AI SDK v6 (not toDataStreamResponse)
• System prompt includes comprehensive Node Banana domain knowledge for conversational workflow planning

Deviations from Plan

Auto-fixed Issues

1. [Rule 3 - Blocking] Fixed google() API usage

• Found during: Task 3 (Create streaming chat endpoint)
• Issue: Plan specified google('gemini-2.5-flash', { apiKey }) but @ai-sdk/google doesn't accept second argument
• Fix: Used createGoogleGenerativeAI({ apiKey }) factory to create provider with custom API key
• Files modified: src/app/api/chat/route.ts
• Verification: Build succeeds
• Committed in: 727e54d (Task 3 commit)

2. [Rule 3 - Blocking] Fixed streaming response method

• Found during: Task 3 (Create streaming chat endpoint)
• Issue: toDataStreamResponse() doesn't exist in AI SDK v6
• Fix: Changed to toTextStreamResponse() which is the correct method
• Files modified: src/app/api/chat/route.ts
• Verification: Build succeeds
• Committed in: 727e54d (Task 3 commit)

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Total deviations: 2 auto-fixed (2 blocking) Impact on plan: Both fixes required for build to succeed. API signature differences between plan and actual AI SDK v6.

Issues Encountered

None beyond the API fixes above.

Next Phase Readiness

• Chat streaming infrastructure complete
• Ready for Chat UI integration in WelcomeModal (31-03)
• Vercel AI SDK useChat hook can connect to /api/chat endpoint

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Phase: 31-workflow-proposal-system Completed: 2026-01-26