Module builder 

Fluent Request Builder for the Claude Messages API

Provides an ergonomic builder pattern for constructing requests:

let response = client.messages()
    .opus()
    .system("You are a Rust expert")
    .user("Explain lifetimes")
    .thinking_adaptive()
    .effort("high")
    .max_tokens(4096)
    .send()
    .await?;

The builder accumulates all parameters, then sends via the parent ClaudeClient.

Structs

MessageRequestBuilder

Fluent builder for Claude API message requests.