Home & field services — spec it like a trades shop runs

HVAC, plumbing, cleaning, landscaping. A crew of techs in trucks, jobs on site, money quoted at the kitchen table. A builder who models this as "appointments + invoices" ships something no contractor will use. This skill is the domain briefing so the spec is right before code starts.

1. Domain vocabulary (know these or look naive)

• Price book — the master catalog of priced tasks ("replace 40-gal water heater = $1,850"). Pricing is looked up, not computed hourly.
• Flat-rate vs T&M — flat-rate (one price from the price book, parts + labor bundled) is the norm in the trades. Time & materials (T&M, billed by the hour + parts) is the exception, used for diagnostics or open-ended jobs. Build for flat-rate first.
• Dispatch board — the live grid of techs × time slots the office uses to assign and re-shuffle jobs through the day.
• Truck roll — sending a tech to a site. Every truck roll has a real cost; minimizing wasted rolls is the whole game.
• First-time fix rate — % of jobs completed on the first visit. The north-star ops metric. Low fix rate = repeat rolls = lost margin.
• Callback — a return visit because the first fix failed. Tracked and hated; ties to warranty.
• Membership / service agreement — recurring plan (e.g. 2 tune-ups/yr for $19/mo) that creates predictable revenue and priority booking. A core business model, not a loyalty gimmick.
• Good-better-best — the quote presents 3 priced options (e.g. patch / replace / replace-with-upgrade). Standard sales technique; lifts ticket.
• Dispatch fee / trip charge — flat fee just to show up, often waived if the job is booked.
• After-hours / emergency rate — premium pricing for nights, weekends, holidays. Same price book, different multiplier.
• GPS / route — tech locations and optimized drive order; drives the "tech is 12 min away" customer text.
• Parts markup — parts billed above cost (often 2–3×); a margin lever, must be representable per line.

2. Non-obvious domain rules (what makes this vertical specific)

• Pricing is a lookup, not arithmetic. The price comes off the price book at a flat rate. Hourly math is the rare path, not the default.
• The quote IS the sales tool. It's presented on site, often on a tablet, and closed on the spot — interactive, branded, good-better-best, accept-and-pay. It is not a PDF emailed for later.
• Techs work offline. Basements, mechanical rooms, rural sites — no signal. The field app must capture work, photos, and signatures offline and sync later. This is a hard requirement, not a nice-to-have.
• Same-day dispatch is normal. Jobs get created, assigned, and re-shuffled within the same day; the board is a live, mutable thing.
• Demand is seasonal and spiky. HVAC floods on the first heat wave / cold snap; landscaping is spring-loaded. Capacity and booking must absorb surge, not assume even flow.
• Appointments are windows, not instants. Customers get "8am–12pm", not "8:00". Model an arrival window plus narrowing ("tech en route").
• Recurring is first-class. Memberships, maintenance plans, seasonal visits — the schema has to express recurrence and renewal natively.

3. What a naive build gets wrong

• ❌ Hourly pricing. Modeling jobs as hours × rate. The trades quote flat-rate off a price book; hourly is the edge case. Get this wrong and the product is unsellable.
• ❌ No offline mode. Assuming the tech has signal. The most common job site is a basement. An online-only field app fails on day one.
• ❌ Quote as static PDF. A read-only document instead of an interactive accept-to-pay surface with selectable options and a deposit button. The quote must close the sale, not describe it.
• ❌ No good-better-best. A single price with no upsell tiers. Leaves margin on the table and feels foreign to anyone who's bought HVAC.
• ❌ No membership / recurring model. Treating every job as one-off. Misses the predictable-revenue engine the whole business runs on.
• ❌ Instant appointments. Booking a 9:00 slot when the trade works in windows. Sets a customer expectation the crew can't meet.

4. Must-model entities / fields (beyond generic CRUD)

Schema hints — keep these migration-friendly (see [[migration-ready-schema]]):

• PriceBookItem — code, name, category, flat_rate, cost, parts_markup, and tier prices {good, better, best}; is_recurring flag for membership-eligible items. T&M items carry an hourly rate as the exception path.
• Membership / ServiceAgreement — plan, cadence (e.g. 2/yr), price, billing_interval, renewal_date, priority_flag, linked customer; generates scheduled visits.
• Job — status (scheduled → dispatched → en_route → on_site → complete → callback), assigned_tech, arrival_window {start,end}, address, is_after_hours, first_time_fix flag, parent membership if recurring.
• Quote — array of options[] (good/better/best), each with line items off the price book; selected_option, deposit_amount, deposit_paid, accepted_at, branding; an accept action that converts to a Job.
• Tech / Crew — skills/licenses held, home base, working hours, current GPS, capacity.

5. Per-product notes (wedge + the one thing to get right)

• dispatch (crud) — assign jobs to techs, optimize routes, live status board. Wedge: ServiceTitan is ~$300+/tech and enterprise-heavy; the wedge is a clean same-day board a 3–8 truck shop can actually run without an implementation consultant. Must get right: the board is live and mutable — jobs re-assign and re-window mid-day, with arrival windows (not instants) and tech status driving the customer "on the way" text.
• quoting (marketplace-lite) — photo/form → priced branded quote → accept + pay deposit. Wedge: vs Jobber/Housecall, lean into the interactive accept-to-pay quote that closes on site. Must get right: good-better-best options priced off the price book, with a deposit step — the quote is the sales tool, not a PDF.
• field-booking (booking) — customer self-books a slot, gets reminders/confirmations. Wedge: incumbents bury self-booking; expose a dead-simple homeowner booking page. Must get right: book into an arrival window against real crew capacity, then drive reminders and confirmations (consent + timing deferred to [[lifecycle-messaging]]).
• reviews (crm) — request/route/publish reviews after each job. Wedge: automate the post-job review ask that shops do by hand. Must get right: fire the request on job completion (tied to the first-time-fix outcome, not a blind blast), route happy → public platforms, unhappy → private recovery; SMS/email mechanics via [[lifecycle-messaging]].

6. Compliance / regulatory touchpoints (light — pointers, not full treatments)

• Trade licensing & permits — HVAC/plumbing/electrical work is licensed and often permit-pulled per jurisdiction. Don't model trade qualification; do let a Job/Tech carry a license/permit reference field so a regulated build can extend it.
• TCPA (SMS reminders) — booking confirmations/reminders are SMS; consent, STOP/HELP, and quiet hours apply. Defer all messaging infra and consent design to [[lifecycle-messaging]] — just flag that reminders exist so it's speced in, not bolted on.
• Deposits / payments — quotes take a deposit and jobs collect payment. Defer PCI scope, idempotency, and refund/dispute flow to the billing/payments layer — the spec only needs the deposit_amount / deposit_paid fields, not the processor design.

Output

When applied, the architect/pm carries these into ARCH-.md / PLAN-.md: the price-book-flat-rate pricing model, the offline field requirement, the window-based scheduling, the multi-option accept-to-pay quote, and the membership/recurring entity — and cross-references [[lifecycle-messaging]], [[migration-ready-schema]], and [[vertical-onboarding]] rather than re-deriving them.