Under the hood
Permission prompts now carry which MCP server is asking, including its name and source
**What
An MCP server is an external tool provider Claude Code can connect to. Permission requests (the prompts asking whether Claude Code may use a tool) can now include an optional mcp_server field with name and source, which is validated and stripped out with a warning if malformed. This information is also passed through to the permission dialog shown to the user, and to the tools that check request formatting.
Why
When a permission request comes from an MCP-provided tool, the person approving it can now see which MCP server is making the request, rather than seeing only the tool name with no indication of which external server it came from.