6-10 wks
To A Production Agent
150-400
Test Cases Before Launch
100%
Code Ownership, Yours
Businesses That Trust Nexona
The Demo Takes Four Days. The Agent Takes Eight Weeks.
Custom AI agent development is four jobs, not one: connect the agent to your real data, define what it is allowed to touch, build an evaluation set that proves it works, then run it where you can watch it. The model itself is about a fifth of the effort. Everything wrapped around the model is the rest.
The first demo always lands. Four days, maybe five, and it answers questions in your tone of voice and everyone in the room goes quiet for a second. Enjoy it. That version would fall over in about nine minutes of real traffic.
One build — a support agent for a company selling industrial valves — spent three of its eight weeks on a single problem. Their part numbers looked like VG-4471-B and customers typed them eleven different ways. Spaces, no spaces, lowercase b, the letter O where a zero should be. The agent kept confidently answering about the wrong valve. Not hallucinating exactly, but close enough that it did not matter what you called it.
Fixing that was not a prompt. It was a normalisation layer and 240 test cases written by someone in their sales team who knew every way a customer could get a part number wrong. That is what the eight weeks is.
- Retrieval agents that answer against your own documents
- Support and voice agents wired into your live systems
- Internal copilots for the team, not for customers
- Multi-agent systems where work is handed between agents
- Evaluation harnesses so changes can be proven, not guessed
- Deployed in your cloud account, monitored, and yours to keep
An Agent Is Not A Chatbot
An AI agent takes a goal, picks its own steps, calls tools to carry them out, then checks whether it actually worked. A chatbot answers and stops. Same model underneath — completely different engineering problem, and a completely different set of ways to get hurt.
Chatbot
Answers a question from what it was given. Has no memory of your systems, cannot act, cannot check itself. Useful for FAQs and not much past that. Fails softly — a wrong answer, and the person moves on.
- —One turn in, one turn out
- —No access to live data
- —Cannot take an action
- —Cheap to build, cheap to be wrong
Agent
Holds a goal across many steps. Reads your live data, calls your systems, decides what to do next, retries when something fails, escalates when it is out of its depth. Fails hard, which is exactly why the guardrails are the build.
- —Many steps, held state
- —Reads and writes real systems
- —Takes actions under explicit limits
- —Needs evaluation before it goes live
Written In Code. On Purpose.
Build a custom AI agent when the agent is the product. Use a no-code platform when it is the plumbing — genuinely, if your problem is moving a form submission into a CRM, go and use one, you will be live this afternoon. That is a different job and it belongs on our AI automation side. Not sure which of the two you need? That call is part of what a fractional CTO is for.
Canvases stop being the right answer at three points, and they are fairly specific points. When you need to prove the thing works before customers touch it. When per-run pricing meets actual volume. When the logic branches in a way you cannot draw. Also — and nobody puts this in the pitch — you are renting. It runs on their infrastructure, under their pricing, and leaving means building it again.
Evaluated
A written test set of real examples the agent has to pass before launch, rerun on every change. You can see the score. So can we.
Owned
Your repo, your cloud account, from week one. No licence, no per-seat fee, nothing running on our side that you pay to keep alive.
Bounded
An explicit list of what the agent may never do alone. Refunds, contracts, prices, money out — draft-and-approve, always.
Agents We Have Actually Shipped
Retrieval Assistants
Answers drawn from your own documents, with the source attached so somebody can check it. Policy manuals, product catalogues, three years of support tickets. Built as an enterprise RAG chatbot most recently.
Voice Agents
Picks up, understands what the caller wants, checks the real system, books or answers or escalates. Our AI voice agent work — latency matters more than cleverness here, by a lot.
Support Agents
Reads the incoming message, pulls the account, drafts a reply, resolves the easy 60% and routes the rest with context attached. See the AI customer support hub.
Browser & Tool Agents
Agents that operate software the way a person would when no API exists. Slow, occasionally uncanny, extremely useful against legacy portals. The agentic web assistant came out of exactly that.
Multi-Tenant Agent Platforms
One agent system, many customers, strict data isolation between them. Harder than it sounds and unforgiving when it goes wrong — see secure multi-tenant chat.
Internal Copilots
Not customer-facing. An agent your own team asks — where is this order, what did we quote them last year, draft the follow-up. Often wired straight into your CRM.
The Decisions That Actually Matter
RAG or fine-tuning?
RAG, nine times out of ten. If the agent does not know your products, prices or policies, that is a retrieval problem — the documents live outside the model, you update them like any other file, and the answer can cite its source. Fine-tuning is for when it knows the facts and still does not sound like you. We have done it twice in three years and undid one.
LangChain or LangGraph?
LangGraph for production, LangChain for the bits around it. LangChain chains steps, which holds up until the agent has to loop, retry, branch or stop and wait for a human. LangGraph makes the run a graph with real state, so you can pause it, resume it, and replay exactly what happened when somebody complains. Sometimes neither — plain Python, no framework, when the job is small. Which is more often than you would guess.
Which model?
Whichever survives your evaluation set, and it changes. We build model-agnostic so swapping is a config change rather than a rewrite, because the frontier moves every few months and you should not be rebuilding each time it does. Cost usually decides it — the cheapest model that passes is the right model.
Where does it run?
Your cloud account. AWS, GCP, Azure, or a box in your own server room if that is genuinely what compliance requires. We deploy into your infrastructure and hand over the keys, which sounds obvious and is not what most of this industry does.
What Drives AI Agent Development Cost
We scope before we quote, so there is no price list here. Three things move the number more than anything else, and none of them is which model you end up on.
Surface Area
How many systems
One job against two systems is the floor. Every extra system the agent has to read from or write into moves the number, and not in a straight line.
Data Condition
How messy it is
Already structured and sitting in a database is cheap. Photographs of printouts are not. Most of the spread in any quote we give comes from this one.
Autonomy
How much it may do alone
An agent that drafts for a human to approve costs less than one allowed to act by itself, because the second needs far more proving before it goes anywhere near a customer.
The one people forget is the running cost. Model usage is billed by volume rather than by seat, so it moves with how hard the agent actually works — which is the opposite of how most software you buy behaves. We put that beside the build price in the proposal. A project that dies in month seven over an API bill nobody mentioned is a project we failed to quote honestly.
Agent Questions We Get Asked
Tell Us What The Agent Has To Get Right
You do not need a spec. One hour, a description of the job you want handled and the things it must never do on its own, and we will tell you whether an agent is even the right shape for it. Sometimes the honest answer is a database query and four lines of code, and we would rather say that than sell you a model.
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