Claude Code v2.1.221 ·
list_changed refreshes can be synthesized after a listen stream reopens
Claude can now tell whether an MCP tool list refresh came from a reconnect or a server notification.
Under the hoodTier: how much it should matter to you
2Useful: my rating, 1 to 5
0Signal: worth watching, 1 to 5
MCPArea: what it touches
Internal ChangesKind: in v2.1.221,
Internal ChangesSection of the release
What
Refresh handlers now know why they ran, so a refetch caused by a reconnect is distinguishable from one caused by a server notification.
Details
- Tools, prompts and resources refresh handlers take a cause argument.
- When the refetch came from a listen-stream reopen rather than a notification, the debug log says so.
- The
tengu_mcp_list_changed event carries a new cause field. - The prompts and resources events moved: they are now emitted after the refresh completes instead of before it starts.
Evidence
Synthesized tools refetch after listen-stream reopen (no notification received)
Strings lifted out of the shipped bundle, so the claim above can be checked against them.
See this entry in the whole of v2.1.221 →
