Pricing Mode

Step 0a: Load the pricing cache

Read references/vendored/pricing/aws-infra-pricing.json. Check _meta.last_updated against _meta.staleness_days (default 30):

• Within the window: cached prices are the primary source. No MCP calls needed for services in the file. Set pricing_source: "cached".
• Past the window: infrastructure prices remain reliable. Use cached rates as fallback with pricing_source: "cached_stale". A cache-miss now goes straight to estimated (if the engine states the formula rate) or unavailable — never to a live lookup.

Each service object carries its rates and (where relevant) a multi_az_handling key. Look rates up from the file — never hardcode them.

Step 0b: Display the pricing mode

Before any calculation, surface the status:

• Cache fresh + all services covered: “Pricing source: cached (updated [date], ±5-10% accuracy). No live pricing API required.”
• Cache stale + services covered: “Pricing source: stale cache (updated [date], ±5-10% accuracy for infrastructure). No live pricing API available.”
• Service not in cache: “Some services not in pricing cache. Those services will show pricing_source: unavailable in the estimate.”

Pricing hierarchy (per-service lookup order)

Row 2 is the documented home of the services_by_source.estimated bucket the shared schema and assemblers carry: a service priced from a rate the cost engine itself states (never a guessed or remembered number) is "estimated", always accompanied by a warning naming the rate and its source. Only a service with no cache entry AND no stated formula rate is "unavailable" and excluded from totals.