Treat vendor-published system prompts as a dependency.

Treat vendor-published system prompts as a dependency. Now that Anthropic publishes Claude’s live system prompts you can stop blaming mysterious “model drift” for behavior changes and start tracing them to concrete text diffs. Diff prompts, pin failing regression cases to the exact prompt version, and alert when upstream edits change safety, routing, or tone assumptions. The practical move is boring: add prompt-version checks in your CI and monitoring so an upstream wording change raises a ticket before it surprises users.