What probably matters to youSection of the release
What
Claude Code's plugin UI framework now includes new provider components, one acting like a SessionProvider and one like a HostProjectProvider, along with useHost and useProject hooks for reading their data. Using either hook outside of its matching provider now throws a clear error message telling the developer it must be called inside a <SessionProvider /> or <HostProjectProvider />.
Why
This gives plugin UI developers a standard, safe way to access host, project, and session information from their components, with a clear error instead of confusing behavior if they're used in the wrong place.
The entry above is what we published on the day. These lines were added later, as Anthropic's own pages caught up, and they sit beside the original rather than replacing it.
Confirmed sinceAnthropic's documentation has since written up useHost, on Blend your MCP App with Claude's theme.* [`useHostStyles(app, hostContext)`](https://modelcontextprotocol.github.io/ext-apps/api/functions/_modelcontextprotocol_ext-apps_react.useHostStyles.html) applies the theme, variables, and fonts and re-applies on `hostcontextchanged`connectors/building/mcp-apps/transparent-themingsee the edit
How sure we are
One source agreesOne thing we can check says the same as this entry.
Anthropic's documentation agreesAnthropic's documentation has since written up useHost, on Blend your MCP App with Claude's theme.
