5. Deterministic rating

The goal

Keep a price, lender requirement, and quote tier out of model-generated prose.

Coverage is a policy boundary

CoverageNode reads the committed vehicle-use channel through this.graph.graphState(), validates the requested coverage against ownership and the quote clock, then builds the rating subject from the registered node channels.

const state = this.graph.graphState();
const use = state.nodes.VehicleNode?.vehicle;
// ...build `coverage` from the tool input...
const error = validateCoverageSelection(coverage, use.ownership, now);
if (error) return reject(error); // stay(JSON.stringify({ accepted: false, error }))

const rating = buildRatingSubject(state.nodes);
if ("error" in rating) return reject(rating.error);

const tiers = RatingEngine.quoteTiers(rating.subject, coverage, now);
this.saveState({ coverage });
this.graph.saveNodeState(QuoteNode, { tiers });
return go(QuoteNode).withMessage(new HumanMessage("Present the quote tiers."));

QuoteNode uses its own quote-present history space, so the transition adds an explicit stage instruction there rather than replaying the intake conversation.

For example, a financed vehicle cannot be quoted as liability-only. The model can explain the rule, but it cannot waive it or calculate a replacement premium.

Seed the presentation atomically

The current coverage belongs to CoverageNode; calculated tiers belong to QuoteNode. The coverage handler writes each channel before routing, so QuoteNode begins with the exact tier list it is allowed to present.

Why it is written this way

The quote changes if any accepted fact changes. A deterministic engine makes that relationship testable and lets the presentation stage answer naturally without owning hidden pricing logic.

Next

Continue to 6. Revisions, direct responses, and acceptance.