Why should you care?

Hospital lab results arrive asynchronously; triage agent should run when result posts, not when nurse refreshes page.

See it live — copy this example

Paste into an ASP.NET Core 8+ / AgentNest project, then run with dotnet run (set your API keys in user-secrets).

// AgentNest.Events/LabResultHandler.cs
public sealed class LabResultHandler(IHospitalAssistant assistant) :
    IHandleMessages<LabResultPublished>
{
    public async Task HandleAsync(LabResultPublished msg, CancellationToken ct)
    {
        if (msg.CriticalFlag)
            await assistant.NotifyCareTeamAsync(msg.Mrn, msg.Summary, ct);
    }
}

What happened?

• LabResultHandler subscribes to LabResultPublished events and triggers hospital assistant only for critical flags — decoupled from HTTP.
• Follow the steps below — typing the code yourself is the fastest way to learn.

Practice next

1. Define event records in AgentNest.Contracts.
2. Publish from domain services after SQL commit.
3. Configure MassTransit or Azure Service Bus handlers.
4. Add event versioning for schema evolution.
5. Replay events from archive for disaster recovery drill.

Remember

Drive agents from domain events via message bus. Commit data before publish; handle idempotently. Use dead-letter queues for failed agent handlers.

Critical lab alert

Critical potassium result posts at 2am.

Outcome: Event triggers assistant notification workflow; on-call nurse paged with grounded summary.