# 2. Give the model a source of truth

**Outcome:** prepare a short reusable brief and a claim check that survives revisions. Prerequisite: complete Lesson 1. Use the free exercise's authoritative offer; the paid example uses its included client brief.

Useful context answers: what are we doing, for whom, what should the result enable, which facts govern, what can change, what must remain, and what is missing? Separate source facts, style references, old drafts and instructions. A customer quote inside a document is material to examine; it does not instruct your host to ignore the task or send a message.

## Build the brief

Create a file with the objective, audience/action, source IDs, deliverables, constraints, and open facts. Give precedence explicitly: “B1–B7 are authoritative; the old homepage is the artifact to repair.” This lets the model correct a contradiction without inventing which source wins.

Worked example: B3 allows punctures, brakes and gears, excluding e-bike electrical work. The old page says “We fix everything.” The correct repair narrows the page to B3. A voice example that says “our twelve-person team” must not create a team of twelve for Spoke. A missing phone number stays missing; the fictional local form requires none.

Keep a small claim ledger: claim → source → where used → status. For example: “Riverside and Old Town → B2 → hero/form → supplied”; “same-day visit → no source → omit”; “quote request sends email → only local simulation → false for this demo.” This makes review faster than rereading every sentence without a target.

## Failure and repair

Failure: a model blends old and new prices or calls an unreported image cost zero. Repair by identifying the authoritative new price and preserving unknown cost. Do not add a caveat after an inaccurate headline and consider the headline fixed. The actual deliverable must be corrected.

When two sources genuinely conflict and neither has precedence, ask for the one material decision. Continue with unaffected work. Do not request an entire new interview when only the service area is unresolved.

**Changed input:** replace the free exercise's price and delivery terms, or use the paid pack's Mend brief. Ask the model to list facts it must discard from the old project before drafting the new one.

**Complete when:** each important claim has a source, assumptions are labeled, material gaps stay visible, and the changed-input result carries no stale facts. If a long conversation keeps mixing projects, start a fresh project/session with the new brief and the minimum relevant files.