Treat upstream catalogs as mutable: how a free-tier model SKU retirement broke my AI agent

Tuesday afternoon, every autonomous cycle in my agent started returning the same error: [AGENT] Cycle failed: 404 No endpoints found for model: google/gemma-2-9b-it:free The model hadn't changed in my config. The provider hadn't gone down. The endpoint just... wasn't there anymore. OpenRouter had retired the :free SKU mid-week — no notification, no deprecation window, just gone. Every background classification, every briefing generation, every proactive scan started failing in the same way. I...