Elicitation Primitive: The Server Asks the User for More Info Mid-Task
~10 min read
Elicitation lets a server request structured user input mid-task — pausing a multi-step workflow to ask for a missing preference or detail, rather than guessing or failing outright.
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Key points
- •Elicitation lets a server request structured user input mid-task, rather than guessing, failing, or requiring everything upfront
- •The book's example: asking for seat preference, room type, or contact number partway through a travel booking
- •This produces a more natural, conversational workflow than a rigid all-fields-upfront form
- •Especially valuable for multi-step tasks where what's needed only becomes clear partway through the workflow
- •Together with Sampling and Roots, this completes the 3 client-side primitives, rounding out MCP's full 6-primitive, genuinely two-way protocol