ChatGPT, Copilot or a custom agent: which is right for your company?
An off-the-shelf tool helps each person; a custom agent does a specific job in your tools, with your rules. How to choose, and when to combine the two.
"Why pay for a custom agent when we already have ChatGPT?" The question is fair, and the honest answer is: sometimes you do not need one. Here is how to decide.
Two families of tools, two uses
Off-the-shelf tools — ChatGPT, Microsoft Copilot, Mistral AI’s Le Chat and others — are assistants. A person asks them a question, gets an answer, and decides what to do with it. They are excellent for writing a first draft, summarising a document, rewording an email, finding an idea.
A custom agent is designed for a specific job: processing supplier invoices, chasing unpaid invoices, qualifying incoming requests. It is connected to your tools, follows your rules, acts without being chased, and hands over to a person when a decision commits the company.
The decision table
| Your need | Off-the-shelf tool | Custom agent |
|---|---|---|
| Help everyone write, summarise, search | ✓ | — |
| Do recurring work without being chased | — | ✓ |
| Act in your tools: CRM, accounting software, email | limited | ✓ |
| Apply your rules: prices, deadlines, tone | every time, by the person | once, in the agent |
| Measure a specific gain | difficult | agreed before starting |
| Initial cost | low, per user | a project, at a fixed price |
When the off-the-shelf tool is enough
- The need is individual: everyone saves a few minutes on their writing.
- The work does not come round in a comparable form.
- You first want to get your teams familiar with AI.
In that case, the essential thing is to write rules of use: which data can be entered, who reviews, which tools are allowed. Without these rules, uses multiply without control. See Your teams already use AI without saying so.
When a custom agent becomes useful
- A task or a process comes round every week, and costs hours.
- The work requires your rules and your data: a generic tool gives an answer that is right for everyone, and wrong for you.
- You want a measured result, not just usage.
- The data is sensitive, and you want to decide where it is processed.
The two can be combined
The most common case: teams use an off-the-shelf assistant for their writing, and one or two agents take on the processes that cost the most. It is not one against the other.
What we do when the off-the-shelf tool is enough
We tell you. It is one of the possible conclusions of our free Flash Diagnostic: if an off-the-shelf tool meets your need, you leave with that answer. And if your teams already use these tools without a framework, the AI Usage Audit takes stock and gives you a usage charter.
Frequently asked questions
Are Copilot or ChatGPT enough for an SME?
To help each person write or summarise, often yes, provided you write rules of use. For work to get done without anyone chasing it — processing invoices, reminding customers —, you need an agent connected to your tools.
Does a custom agent cost much more?
It requires an initial investment, from a few thousand euros for a task. In return, it does measurable work. A per-user subscription costs little at the start, but guarantees no gain.
Can an agent be built from ChatGPT or Copilot?
Some off-the-shelf tools allow it, for simple cases. As soon as several tools must be connected, company-specific rules applied and decisions kept in human hands, the design work remains the same.