What
Tools provided by MCP (Model Context Protocol) servers now carry structured metadata describing the server that's serving them: the server's configuration key name, and a source value drawn from a fixed set of options (sdk, plugin, user, project, local, dynamic, managed, enterprise, claudeai, agent) describing where that server's definition came from. The tool-wrapper builder now threads this source value through into the tool's metadata.
Why
The metadata explicitly instructs consumers to trust the source field, not the tool's name or its mcp__ prefix, for security purposes. This closes a gap where a tool's name or prefix alone could be spoofed or misleading about where it actually came from.