What
MCP (Model Context Protocol, the standard Claude Code uses to connect external tools) tools can now carry extra metadata that controls how they show up:
- A hidden-from-model marker that removes the tool from the list the model sees, so it never gets called even though it's registered.
- A
uiMetapayload carried alongside the tool definition. - An
accountMemoryflag marking tools that come from account-memory servers.
Building on the earlier _meta fields that let MCP tool authors set result-size caps and similar behavior, this adds the ability to keep a tool registered but invisible to the model, and to distinguish account-memory-backed tools from others.
Why
This lets MCP server authors register tools that exist for bookkeeping or UI purposes without cluttering the model's tool list or risking it calling them by mistake.