Build Cost Estimator
Costs the project from your own rates, and names what it excluded
- 8hard rules
- Things it must never do, enforced in every run
- 5handover rules
- Conditions where it stops and gives the work to a person
- 10output fields
- A structured result, not a paragraph you have to re-read
- ≤6steps per run
- Bounded work: at most 5 tool calls, enforced by the runtime
Read-only by design. This agent has no path to sending, spending, publishing or committing anything. Where that limit is the product, removing it would remove the reason to trust the output.
Overview
Estimating software sells you a national average adjusted by a location factor. Every builder knows that number is wrong for them, because the one that matters is what this business paid these suppliers in this city last quarter — which no database holds.
This agent estimates from your own data: your rate card, your recent projects, the quotes you have on file. It works by specification level, so a shell, a finished building and a finished and furnished one are three separate answers rather than one number with a shrug, and every rate carries where it came from and how old it is.
The part that saves the money is the exclusions list. Projects rarely overrun because a rate was slightly wrong; they overrun because the estimate silently excluded site works, connections, temporary works or fees, and nobody recorded that it had. Here everything outside the number is written down, and anything with no rate behind it is reported as unpriced rather than filled with an average.
Benefits
Estimates you can defend
Every rate traceable to a project or a quote you actually hold.
The overrun found early
In the exclusions list rather than in month six.
Faster than the spreadsheet
And it does not carry last project's mistakes forward.
What it does
Your rates, not a national average
What you actually paid, from your rate card and your past projects, with the date on each.
Three specification levels, three answers
Shell, finished, finished and furnished. One number covering all three is not an estimate.
Writes down what it excluded
Site works, connections, temporary works, fees. Projects overrun on the exclusions nobody recorded, not on the rate.
Unpriced is unpriced
An item with no rate behind it is reported as such, never filled in with something plausible.
Ages every rate
A rate from eighteen months ago is labelled as one. Materials move, and a stale rate is a quiet loss.
States the confidence
Built from three past projects or from thirty — the answer looks the same and is not.
What this changes
What this changes about your week
- It takes over
- Pricing a project from a spreadsheet that carries last project's mistakes forward.
- Done today by
- The owner or an estimator, under time pressure, before a deadline.
- How often
- Every enquiry.
- Typical manual effort
- A defensible estimate is a day per project.
Why Construction in particular. Estimating software sells a national average adjusted by a location factor, which every builder knows is wrong for them. This uses what you actually paid — and writes down the exclusions, which is where projects overrun rather than on the rate.
Runs unattended
Started by you or by an event, and it finishes on its own. Nothing waits for someone to be at a desk.
The same standard every time
The two-hundredth item is held to the bar the first one was. Consistency is the part people cannot sustain.
It cannot act on its own
Build Cost Estimator has no path to sending, spending or committing. That limit is why its output is safe to act on.
How it runs
This agent runs server-side through the PROMIVO runtime. Each run is logged step by step and every tool call is permission-checked before it executes.
- 1InputValidated against the agent input schema
- 2Modelclaude-opus-5 with automatic fallback
- 3Toolssearch_knowledge, extract_structured_data
- 4PermissionsRuns READ actions automatically; anything higher waits for approval
- 5OutputStructured result matching the output schema
- 6LoggingTokens, duration and every step recorded
Demo
Demo dataIllustrative sample output, abridged.
Input
{
"currency": "USD",
"grossSqm": 440,
"projectType": "Villa",
"specificationLevels": [
"shell",
"finished",
"finished-furnished"
]
}Output
{
"escalate": true,
"unpriced": [
{
"element": "Furniture and loose fittings",
"whatWouldPriceIt": "A supplier schedule from one completed furnished project, or a current FF&E quote."
}
],
"estimates": [
{
"level": "shell",
"totalLow": 180400,
"perSqmLow": 410,
"totalHigh": 204600,
"confidence": "medium",
"perSqmHigh": 465,
"confidenceBasis": "Four of your projects in the last 14 months, two of them a similar size."
},
{
"level": "finished-furnished",
"totalLow": 0,
"perSqmLow": 0,
"totalHigh": 0,
"confidence": "low",
"perSqmHigh": 0,
"confidenceBasis": "You have no furnished project in the data. This level cannot be estimated from your rates."
}
],
"disclaimer": "An estimate from your own rates, for a person to check. Not a quotation, not a tender price, not a cost plan, and no national or published rates were used.",
"exclusions": [
"Site clearance and earthworks — no rate in your data.",
"Utility connections and authority fees.",
"Professional fees.",
"Contingency. None has been added; add your own.",
"Tax."
],
"inclusions": [
"Substructure, frame, envelope, internal finishes at the level stated."
],
"ratesFound": true,
"disagreements": [
"Blockwork appears at 26 and 34 per m² in two projects six weeks apart. Both are shown; neither has been averaged."
],
"escalationReason": "The furnished level cannot be estimated — you hold no furnished project to price it from."
}Requirements
Integrations
No integrations required.
Before you start
- The areas and specification level
- A knowledge base holding your rate card, past project costs or supplier quotes
- Requires the All-Access plan or higher
Use cases
Pricing a new enquiry
A defensible range from your own history, in minutes.
Budget conversations
What the client's number actually buys, by specification level.
Reviewing a subcontractor's price
Against what you have paid before for the same work.
Pricing
All-Access
Billed monthly through your PROMIVO subscription. Cancel at any time.
Runs consume your plan allowance for agent executions and tokens. See plan limits
FAQ
Does it include a cost database?
No, deliberately. A national average adjusted by a location factor is wrong for your business, and selling you one would be selling confidence. It uses your rates, and says so when you have none for something.
What if we have no historic data?
It reports the items as unpriced and tells you which rates to establish first. That list is worth more than an invented total, which you would find out when the tender came back.
Is this a formal cost plan?
No. It is an estimate from your own data for a person to check. A cost plan issued to a client is a quantity surveyor's document with their name on it.
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