00 Setup

Learner guide: 00 Setup

Instructor notes

• Use checkpoint/00-setup as the stable base-app checkout. It should be equivalent to checkpoint/01-base-app, not the complete reference app.
• main contains the complete reference implementation, but learners should use the checkpoint so setup and base-app orientation share the same starting state.
• Make learners confirm both URLs: Vite on 127.0.0.1:3333, Express on 127.0.0.1:8787.
• Emphasize the EU Langfuse host value: LANGFUSE_BASE_URL=https://cloud.langfuse.com.
• The Node server and helper scripts load the repository .env with override enabled, so stale exported LANGFUSE_*, OPENAI_*, or DATASET_NAME values from another local project should not win. Have learners edit .env when they need to switch keys or projects.
• Do not frontload Project Settings → LLM Connections here. Learners configure the default evaluator model in 04-monitoring, when LLM-as-a-judge evaluators first become relevant.
• Keep key handling explicit: real API keys go only into .env or Langfuse secret fields, never into shared transcripts, notes, or chat.
• After one successful chat turn, have learners switch to checkpoint/02-tracing for the first build step.

Watch for

• Missing .env values. The app may render while model calls fail.
• Learners editing shell exports instead of .env. The workshop intentionally treats .env as the Node-side source of truth.
• People expecting evaluator setup during initial setup. The app can run and trace correctly before the Langfuse-side LLM connection exists.
• People expecting traces on checkpoint/00-setup or checkpoint/01-base-app. Both are intentionally untraced; tracing starts only after the 02-tracing edits.
• People staying on main for tracing. main is already the finished reference implementation.

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