Do I need ChatGPT Plus to build a custom GPT?

Building and sharing custom GPTs requires a paid ChatGPT plan. If you're not on one, the same effect is available for free by saving your instruction block as a text note and pasting it at the top of a new conversation, or by using a Claude Project.

How do I stop AI from making up prices for my jobs?

Put an explicit hard rule in the instructions telling it never to invent a price and to ask you instead, then test it by requesting a quote with no rates supplied. Supply your rate card as an upload so the arithmetic runs against real numbers.

Can my whole office team use the same custom GPT?

Yes. Share it within your workspace so everyone works from the same rules and rate card. That consistency is most of the value — it's how estimates from three different people end up reading like one company.

CRM Integrations

Build a Custom GPT That Knows Your Pricing, Your Crew and Your Voice

6 min read Verified by the TradePrompt Field TeamUpdated July 14, 2026

Every prompt in this library gets better when the model already knows who you are. A custom GPT — or a Claude Project, or a saved system prompt — is just a container for the context you'd otherwise paste every single time.

It takes about thirty minutes to build and it's the highest-leverage half hour in this whole library.

On this page

What goes in the instructions
What to upload as knowledge
Test it like you'd test a new hire
Keep it current

What goes in the instructions

The instruction field is where you encode identity and rules. Keep it under about 1,500 words; longer instructions get diluted.

Custom GPT Instruction Template

Fill the brackets and paste into the Instructions field.

You are the office assistant for [COMPANY NAME], a [TRADE] contractor serving [SERVICE AREA]. You help the owner and office staff write estimates, customer communication, safety documents and marketing copy.

ABOUT US
- Trades: [list]
- Typical jobs: [list your 5 most common job types]
- Crew size: [X]
- License numbers / certifications worth mentioning: [list]
- What makes us different, stated plainly: [1-2 sentences]

VOICE
- Direct, plain-spoken, sixth-to-eighth grade reading level.
- Never use: "delighted", "thrilled", "valued customer", "excited to", "reach out", exclamation marks, emojis.
- Short sentences. No marketing hype. Explain, don't sell.

HARD RULES
1. NEVER invent a price, rate, part cost or lead time. If pricing is needed and I have not supplied it, ask me.
2. NEVER state a code, regulation or permit requirement as fact. Flag it as [VERIFY: ...] instead.
3. NEVER promise a completion date, a warranty term, or a guarantee I have not stated.
4. Never write anything that criticizes a named competitor or a previous contractor's work.
5. If a request involves safety-critical procedure, add a line telling me a competent person must review it.

DEFAULTS
- Currency: [USD]. Measurements: [imperial].
- Labor rate placeholder: $[X]/hr loaded. Material markup: [X]%.
- Owner name for sign-offs: [NAME]. Phone: [PHONE].

WHEN I ASK FOR SOMETHING VAGUE
Ask me at most 3 clarifying questions, then produce a draft. Never stall waiting for perfect information.

What to upload as knowledge

Uploads are where the specifics live. Keep them short, plain-text where possible, and versioned.

Your rate card: labor rates, common material costs, markup, minimum charge.
Two or three of your best past proposals — the ones that closed.
Your standard exclusions and assumptions list.
Your warranty terms, verbatim.
Your service area list, and any areas you refuse.
Three past review replies you were happy with, for tone calibration.

Test it like you'd test a new hire

Before you trust it, try to break it. Ask it to price a job you never gave it rates for and confirm it asks rather than guesses. Ask it whether a permit is required and confirm it flags rather than answers. Ask it to write something enthusiastic and confirm it stays in your voice.

Anything that fails the test becomes a new line in the HARD RULES section. Two or three rounds of this and it's genuinely useful.

Keep it current

A rate card from eighteen months ago is worse than no rate card, because you'll trust the output. Put a quarterly calendar reminder to re-upload pricing, and re-read the instructions any time you add a service line or a service area.