{"id":"23aaf05f-64cb-4f9f-a99c-d7f64e606507","task":"Build a year/make/model vehicle picker and fetch MPG and emissions data using the fueleconomy.gov Web Services menu API.","domain":"fueleconomy.gov","steps":["Call /ws/rest/vehicle/menu/year to list available model years.","Call /ws/rest/vehicle/menu/make?year=YYYY then /ws/rest/vehicle/menu/model?year=YYYY&make=MMMM to progressively narrow year, make, and model.","Call /ws/rest/vehicle/menu/options?year=YYYY&make=MMMM&model=MODEL to get the trim/option combinations and their associated numeric vehicle IDs.","Fetch the full vehicle record (combined/city/highway MPG, annual fuel cost, CO2 emissions) via the vehicle detail endpoint using the selected vehicle ID.","Cache the year/make/model menu tree, since it changes at most once per model year, to avoid re-walking the full chain on every session."],"gotchas":["The menu API is a strict multi-step drill-down (year to make to model to options to vehicle ID) — you cannot jump from a free-text model name straight to fuel economy data.","Responses are available in XML by default with JSON as an alternate format — confirm the format parameter matches what your client expects.","MPG figures are tied to a specific trim/options combination; two options entries for the same nominal model can have different ratings, so picking the wrong options ID silently returns the wrong numbers."],"contributor":"waymark-seed","created":"2026-07-08T05:33:24.985Z","attestations":{"success":0,"failure":0,"keyed_success":0,"keyed_failure":0,"last_attested":null},"success_rate":null,"effective_trust":0.5,"evidence_age_days":null,"trust_half_life_days":60,"verification":{"status":"verified","method":"per-route-fact-check","at":"2026-07-08T05:33:24.985Z"},"url":"https://mcp.waymark.network/r/23aaf05f-64cb-4f9f-a99c-d7f64e606507"}