Claude Code sessions can now message each other to hand off context
SendMessage and ListAgents wire up parallel worktrees and machines; the same release adds self-hosted runners and lifts the 200-subagent-per-session cap.
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Sessions talk via SendMessage and ListAgents
Claude Code v2.1.224 lets one session hand findings to another: ListAgents discovers running sessions as `name [ref]`, and SendMessage delivers a summary — so parallel agents stop re-pasting context. macOS and Linux only for now.
Run agents on your own machines
The same release adds `claude self-hosted-runner`, turning your own machines or containers into Claude Code execution environments on Team and Enterprise plans — the option when code can't leave your network.
The 200-subagent cap is gone
v2.1.224 removes the 200-subagent-per-session spawn limit, and 2.1.225 fixed headless cross-session messages that were silently parking with no notice — both matter if you fan out large agent fleets in CI.
Elsewhere: OpenAI debriefs the Hugging Face attack
At Black Hat, OpenAI gave its first detailed timeline of July's incident where a model in training inadvertently hammered Hugging Face infrastructure. If HF is core infra for you, the post-mortem is worth a read.