Writing the Brain, Section by Section
10 min read
The Brain has six sections, and the whole thing should fit in two to three pages. Longer is not better: every extra paragraph is something to keep current, and a bloated Brain gets skimmed by you and by the assistant alike. We will write each section for the HVAC company you have been following, and you will write yours alongside.
1. The Basics
Ten lines, no more. Who you are, what you do, where, for whom, and how customers reach you.
## The Basics
Reliable Air Heating & Cooling. Residential HVAC: furnace
and AC install, repair, and maintenance plans. Two trucks,
two licensed techs, one office manager. Service area:
Hamilton and within 40 km. Hours: Mon-Fri 7:30-17:00,
emergency line after hours. Booking by phone or website
form. In business 11 years.2. Offers and Prices
The complete rate card, plus what each service includes and does not include. This is the section the drift problem hits hardest, so be exhaustive here even while staying brief everywhere else. If a price varies, state the range and what moves it.
## Offers and Prices
Service call: $149, includes diagnosis and first 30 min.
Furnace install: $4,800-$7,200 depending on unit and ductwork.
Maintenance plan: $22/mo, one tune-up per season, priority
booking, 10% off repairs. Does not include parts.
[... full rate card continues ...]3. Customers
Your two or three real customer types, in a sentence each, with what each cares about. This is what stops the assistant writing for a generic "customer" who does not exist.
## Customers
1. Homeowners 45+, own their HVAC decisions, care about
reliability and not being upsold. Biggest segment.
2. Landlords with 2-10 units, care about response time and
invoices their bookkeeper can process without questions.
3. New-build contractors, price-sensitive, book in batches.4. Voice
Five to eight rules, each one concrete enough to check a draft against. "Friendly but professional" fails that test; the rules below pass it.
## Voice
- Plain words. "Fix" not "remediate," "check" not "assess."
- Short sentences. If a sentence needs a comma map, split it.
- Specific over impressive: name the part, the price, the day.
- No exclamation marks in quotes or invoices.
- We say "we" and sign with a first name, not the company name.5. Policies and Red Lines
Standing commitments and hard limits. These become rules every skill inherits without you repeating them in each skill file.
## Policies and Red Lines
- Quotes are valid 30 days and say so.
- 50% deposit on installs over $2,000, balance on completion.
- We match written competitor quotes on identical equipment.
- We do not badmouth competitors in any customer-facing text.
- Warranty claims: never promise coverage before the tech
confirms; say "we'll confirm coverage when we inspect."6. Right Now
The only section with an expiry date, and the reason the Brain stays useful instead of going quietly stale. Date it, keep it short, rewrite it monthly.
## Right Now (updated 2026-08-04)
- Fall tune-up promotion runs Sept 2 to Oct 17: $99 instead
of $149 for maintenance-plan signups.
- Marek is on vacation Aug 18-29; do not promise install
dates in that window.
- We are hiring a third tech; mention the careers page when
it fits naturally.Assembly
Write your six sections in one sitting, using the duplicate list from the last lesson as your source material. Where two skills disagreed on a fact, settle it now and note the settled version. Save the file as `brain-2026-08.md` in your `/brain` folder, and move any older context documents to `/archive`.
Try it now
Test the Brain before you trust it. Open a fresh conversation, paste the Brain and nothing else, and ask: "Based only on this document, quote a furnace install for a landlord, and tell me what you still need to know." A good Brain produces a draft in your voice with the right prices and a short list of genuinely missing facts. Whatever the assistant asks for that surprised you belongs in the Brain. Add it, and run the test once more.