Under the hoodTier: how much it should matter to you
2Useful: my rating, 1 to 5
3Signal: worth watching, 1 to 5
TelemetryArea: what it touches
Internal ChangesKind: in v2.1.299,
Internal ChangesSection of the release
What
Each tool Claude can use comes with a description the model reads. Claude Code now checks whether any of these descriptions has changed since it was first recorded in the session, and logs a tool_redescribed event when one has. Tools that are loaded only when needed are not checked.
Why
This is a diagnostic. The prompt cache lets Claude reuse the start of a conversation it has already processed, which saves time and cost, and a tool description changing partway through breaks that reuse. The event helps track down when that happens.
