AI agent glossary
MCP elicitation
An MCP feature that lets a server ask the user for input partway through a request, such as a confirmation or a missing detail, through the client's interface.
Some tool calls cannot finish without a person: a required detail is missing, or the action deserves explicit approval. Elicitation lets the server ask the user directly, rather than relying on the model to relay the question.
In the 2026-07-28 spec revision, the server answers a tool call by saying input is required and describing what it needs; the client shows the request to the user and repeats the call with the answer. Nothing is held in server memory between rounds, which suits remote servers.
There are two modes. Form mode shows a simple form, and the answer passes through the client. URL mode sends the user to a web page, which keeps sensitive input such as sign-ins, payments, or API keys out of the client and the model's context.
A notes server's delete tool replies that it needs confirmation. The user sees a 'Move q3-plan.md to the trash?' prompt, confirms, and the client retries the call with that answer.
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