01 Base App

The base app is already in the repo. Nothing to build in this chapter — just orient yourself before tracing starts in 02-tracing.

What the running app does

• Dad himself is the user. Specs (the agent) talks directly to him about his iPhone.
• One OpenAI tool-calling loop. Two local tools (get_support_context, search_help_library).
• The system prompt is rendered locally from src/server/support-agent.ts. No Langfuse yet.

Where to look in the code

• src/client/App.tsx — chat UI + side panel
• src/server/index.ts — Express routes
• src/server/support-agent.ts — the tool-calling loop you'll instrument in 02-tracing
• src/server/tools.ts — tool definitions and executeTool(...)
• src/server/support-data.ts — Dad's fixed context + guide library
• src/server/support-agent.ts — system-prompt template

Bonus

You can customize your experience by changing the phone specs in support-data.ts file. Adding your dad's phone information means, you will get replies for the right type of phone.

End state

You are ready to start 02-tracing.

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