Conversational elicitation of strongly-typed Rust values via MCP.

The elicitation library provides a trait-based system for eliciting strongly-typed values from users through conversational interaction via the Model Context Protocol (MCP). It transforms LLM conversations into type-safe Rust values with compile-time guarantees.

MCP Setup Required

This library runs as an MCP server and requires an MCP client (like Claude Desktop or Claude CLI) to provide the elicitation tools. Your application won't work standalone - it must be invoked by an MCP client.

See the README for setup instructions.

Core Concepts

Traits

• [Prompt] - Provides prompt metadata for a type
• [Elicit] - Main trait for eliciting values

Interaction Paradigms

• [Select] - Choose from finite options (enum pattern)
• [Affirm] - Yes/no confirmation (bool pattern)
• [Survey] - Multi-field elicitation (struct pattern)
• [Authorize] - Permission policies (planned for v0.2.0)

Example

use elicitation::{Elicit, ElicitResult};

# async fn example<T: pmcp::shared::transport::Transport>(client: &pmcp::Client<T>) -> ElicitResult<()> {
// Elicit a simple integer
let age: i32 = i32::elicit(client).await?;

// Elicit an optional value
let nickname: Option<String> = Option::<String>::elicit(client).await?;

// Elicit a collection
let scores: Vec<i32> = Vec::<i32>::elicit(client).await?;
# Ok(())
# }

Derive Macros

The library provides derive macros for automatic implementation:

use elicitation::Elicit;

// Enums automatically use the Select paradigm
#[derive(Elicit)]
enum Color {
    Red,
    Green,
    Blue,
}

// Structs automatically use the Survey paradigm
#[derive(Elicit)]
struct Person {
    #[prompt("What is your name?")]
    name: String,
    #[prompt("What is your age?")]
    age: u8,
}

MCP Integration

The library uses the pmcp crate for high-performance MCP client integration. All elicitation happens through asynchronous MCP tool calls.