You'll notice
Spawned subagents can now use machine-level MCP tools, not just app-state and agent-declared ones
What
When Claude Code figures out which tools a spawned subagent is allowed to use, it now also includes machine-level MCP (Model Context Protocol, a standard for connecting external tools) tools, in addition to the app-state MCP tools and the tools an agent explicitly declares. This applies both to subagent spawning generally and to the workflow SDK's agent tool-set resolution, and the machine-level tool list is now merged in when building skill tool sets as well.
Why
This broadens what tools a subagent can reach, so machine-wide MCP tool configurations are no longer left out when a subagent's tool set is computed.