Problems / Agents and tools, medium
Agent jobs are queued and run by workers. When an acknowledgement is lost, the queue redelivers and the job’s side effect (sending an email) happens twice.
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No duplicate side effects.
Like a coding problem, a solution has to pass every case, not just the one it was built for. Submit in the lab runs all 6; 2 of them are hidden until then.
30 requests a second for 30 seconds: 100% job (writes).
What each component does in this design, and what calls it. The simulator mimics each one from these settings.
| Component | Its job here | Settings |
|---|---|---|
| Load balancerLoad balancer | Traffic enters here.Calls Agent API.Layer 4 balancers route by IP and port; layer 7 balancers read HTTP and can route by path or header. | – |
| Agent APIApp service | Load balancer forwards to it.Calls Agent job queue (publishes).Little's law: throughput ≈ concurrency ÷ latency. 200 slots at 50 ms serve about 4,000 req/s. | 3 replicas × 500 slots · timeout 30 s |
| Agent job queueMessage queue | Agent API publishes to it.Calls Agent workers.If a consumer does not finish within the visibility timeout, the message is delivered again. | – |
| Agent workersWorker | Agent job queue consumes from it.Calls Email tool.Queues deliver at least once, so a worker can see the same message twice. | 32 concurrent jobs |
| Email toolTool / MCP server | Agent workers calls it.Tools give the model actions such as search or database queries; each call is another round trip. | 200 slots |