You'll noticeTier: how much it should matter to you
2Useful: my rating, 1 to 5
2Signal: worth watching, 1 to 5
Tool ListingArea: what it touches
ImprovementsKind: in v2.1.280,
ImprovementsSection of the release
What
Claude Code now separately tracks tools whose definition (schema) was replaced, instead of lumping them in with tools that were simply added or removed. This is tracked internally as replacedNames.
A new notice, 'tools have updated definitions', appears when a tool you already had access to gets a new schema pushed to it.
A new transcript entry type (tool_hosts_correction) and new reminder text groupings (such as 'the following tools were replaced') support this distinction in the session transcript.
Why
Previously, replacing a tool's definition looked the same as adding or removing a tool, which could be confusing when reading back what happened in a session. Now the notices are more precise about what actually changed.
