You'll notice
A tool whose MCP server disconnected now tells the model to continue without it and that it will work again on reconnect.
When a tool is still declared for the conversation but its provider (for example an MCP server) has disconnected, the tool-not-available error now returns a distinct message telling the model the tool can't run right now, to continue without it, and that it will work again if it reconnects, instead of the generic unavailability message.