201-04 — RAG and evidence

What you will build

An offline run of answer_from_evidence using stub evidence and deterministic fake_chat JSON—mirrors integration patterns without retrieval infra.

Prerequisites

• 201-03
• Skim RAG and Task catalog RAG rows

Files you will touch

examples/rag/answer_from_evidence_fake.py

Step 1 — Run the maintained example

PYTHONPATH=src python3 examples/rag/answer_from_evidence_fake.py

Step 2 — Read the payload shape

Open the script: note question, evidence map (evidence id → snippet), and fake_chat returning JSON with answer, citations, confidence.

Step 3 — Break it intentionally

Temporarily return malformed JSON from fake_chat on a branch (do not commit) and observe Err—then revert.

Expected output

Successful run prints Ok with answer payload satisfying answer_from_evidence output schema.

Common failures

Verify

PYTHONPATH=src python3 examples/rag/answer_from_evidence_fake.py | grep -q Ok && echo OK

Optional live path

Live retrieval + gateways belong in consumer services—not required here. See live Granite tests.

Next step

201-05 — Verification and repair.