A Kiwi builder turned sleepless nights into an AI tool for job budgets
In plain words
After losing sleep over blown job budgets, a tradie built Formal Tradie: real-time project budget tracking with an AI agent for construction firms.
Still a trial: Launched as a product; results still early.
Source: nzherald.co.nz ↗
How to do it yourself
Our suggested steps. The company didn't publish theirs.
- 1
Set up a sheet per job: quoted cost per line, actual cost so far, % complete.
- 2
Every Friday, paste it into ChatGPT with the prompt below.
- 3
Act on the jobs it flags as heading over budget.
- 4
Ask it to draft variation notices when the client changed scope.
- 5
Keep the weekly summaries for your accountant.
The instructions to give the AI
Paste this into ChatGPT (the free plan is fine), swap the [brackets] for your details, and test it on a few real examples.
Agent instructions (prompt)
Here's my job-costing sheet for [job]. Compare spend vs quote against % complete. Tell me: which lines are heading over, projected final cost, margin left, and what I should do this week. Draft a variation note for any client-driven changes. [paste]
[Highlighted] = replace with your own details before you run it.
What you should get back: "Plumbing is 18% over budget at 60% done; electrical is fine. Talk to the plumber about variations."
Written by Quickly and Good, inspired by this case.
More detail: tools, prices and what you'll need
The company used: Custom AI agent
You could use: ChatGPT or Claude + a job-costing spreadsheet
- ChatGPT
General AI assistant: writes, summarises and answers from files you give it.
Free plan; paid plans available · Official site ↗
- Claude
AI assistant for writing, analysis and long documents; can connect to your tools.
Free plan; Pro $20/mo (monthly) · Official site ↗
Prices from each tool's own pricing page, checked Oct 2026.
What you'll need
- ☐A ChatGPT or Claude account
- ☐Your own documents, templates or examples
- ☐The agent instructions (prompt)
- ☐A habit of checking every output before you use it
Can I do this myself?
Yes. You can try this today with a chat assistant and your own files.
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