An agent routing system identifies agents by their model name (e.g., "claude-3-opus"). The provider releases a new model version under a different name. What breaks?
Answer: The routing table no longer matches any registered agent because the model name changed
Routing on model name creates a brittle dependency on naming conventions that the provider controls. When the model is renamed or versioned (claude-3-opus → claude-opus-4), the routing table entries no longer match any live agent — every route that referenced the old name breaks. Capability-based routing, where agents declare what they can do in a structured schema rather than advertising their model name, is resilient to these changes: the routing key is the declared capability, not the model identity. The other options describe incorrect failure modes — providers do not invalidate API keys on model renames, and whitelisting happens in access control systems, not system prompts.