What is a custom AI agent?
Start with a useful job.
A focused application can use approved information and tools to prepare work. The task and its limits determine whether an agent is useful.
BeAIgency editorial. Reviewed 27 October 2026.
Prepare a client briefing.
Read the allowed project notes.
Retrieve information; propose the next step.
Check the brief before acting.
Task: the result a person needs
Write the useful output in plain language. “Prepare a project brief from approved sources” is easier to judge than “make our agency intelligent.” Specify the user and the decision the result supports. A task that cannot be evaluated is not ready for a production commitment.
Context: the information it may use
Identify current source material and the user’s access rights. More information is not automatically better. Contradictory documents, old policies and unrelated records can make the answer less dependable. Retrieval should preserve a reference to the evidence behind important claims.
Tools: the actions it may request
A tool is a controlled interface to an operation. Reading a project record and sending a customer message have different consequences. Define the permitted input, permission boundary and failure result for each tool. Keep credentials on the server and verify authorization independently of the model.
Evaluation: the behavior you will accept
Test representative requests, ambiguous inputs, missing information and attempts to exceed the task. Review source accuracy and tool behavior separately from writing style. A fluent answer can still be wrong or unauthorized. The release decision should use the agreed acceptance criteria.
Evaluate the useful result.
Use representative questions, missing information and requests outside the allowed task. Check source accuracy, useful output and tool permissions separately. Agree what must reach a person before the application is released.