Trip builder

Chat with an assistant about a trip, get a personal itinerary app for it.

Two agents:

• Chat interviews, thinks, and writes a brief. No web search, so it stays quick.
• Builder never talks to anyone. It takes one brief, researches the destination properly, and produces the itinerary through custom tools.

The renderer in renderer/render.js is shared with tools/itinerary-generator in the vault repo, and turns one itinerary JSON into the same app shape as the Phu Quoc trip it was extracted from.

No storage anywhere

The itinerary is never written to a database. It is replayed from the builder session's own event log, and the builder session id is recovered from the chat session's log. The event log is the database.

People are separated by an anonymous session id in their own localStorage. No accounts, no links.

Why polling

A build takes minutes, longer than a serverless function lives. /api/send returns immediately and the client polls /api/state; each poll resolves whatever tool calls are pending right now and returns. The chat keeps talking while the builder is still researching.

Setup

Agents are persisted objects, created once:

node --env-file=.env setup/create-agent.js     # first time only
node --env-file=.env setup/update-agent.js     # to change a prompt

Ids live in lib/config.js. ANTHROPIC_API_KEY is read from the environment if set, with a fallback in lib/config.js.

The agent's prompt and tool schemas live on Anthropic's servers, not in the deploy. Editing lib/prompt.js, lib/editTools.js or any other tool schema changes nothing anybody can see until update-agent.js runs. No build step does it and a Vercel deploy will not. This has twice produced a change that looks shipped, reads shipped in the diff, and is inert — so GET /api/health?sources=1 reports chatAgent, which is either ok (vN) or tells you exactly what has drifted and to run the script.

Tests

node --env-file=.env setup/test-builder.js   # builder alone
node setup/test-ui.js                        # full flow through the real UI