A small, embeddable agent framework in Rust.

let mut agent = Agent::builder()
    .provider(provider)      // the only model seam
    .resolver(tools)         // the capability seam
    .system("you are a helpful agent")
    .params(ChatParams::new("model-id"))
    .build()?;

let mut session = Session::default();  // caller-owned
session.history.push(Message::text(
    Role::User, "run the echo tool, then summarize"));

// one exchange: request in, reply and results out
let step = agent.step(
    &mut session, &mut sink, &ctx).await?;

// the provided turn loop, from rhema-core
pub async fn run_turn(
    agent: &mut Agent,
    session: &mut Session,
    input: Message,
    sink: &mut dyn EventSink,
    ctx: &ToolContext,
    max_iterations: u32,
) -> Result<ModelOutput, AgentError> {
    session.history.push(input);
    for _ in 0..max_iterations {
        let step = agent.step(session, sink, ctx).await?;
        if step.output.stop_reason != StopReason::ToolUse {
            return Ok(step.output);
        }
    }
    Err(AgentError::MaxIterations(max_iterations))
}