Unit 11 · Ship AI systems you can operate

Fall back without changing your app contract

You route across models by capability, health, latency, price, or application policy. A fallback preserves the typed contract and remains observable.

9 focused minutesNot started

Unit example (nearest native match)

See the idea in context

set_usage_observer(Some(Arc::new(move |event| {
    usage_queue.lock().unwrap().push(event);
})));
client.chat_with_options(request, json!({
    "usageContext": {"tenantId": tenant_id, "userId": user_id, "requestId": request_id}
}))?;

Run itIn your own project

cargo add axllm

use axllm::{ai, ax};
use serde_json::json;

let llm = ai("openai", json!({"apiKey": std::env::var("OPENAI_API_KEY")?}))?;
let classify = ax("review:string -> sentiment:class \"positive, negative, neutral\"")?;

Set OPENAI_APIKEY in your environment before running provider-backed code.

In the ax repo

From a clone of the ax repo:

npm run example -- rust src/examples/rust/long-agents/smart_defaults_agent.rs

Active practice

Show that you can use it

Answer 2 in a row to learn this · attempt 1

Keep exploring

See the idea in context

Show that you can use it

Source-backed follow-up