The explicit TeamCreate and TeamDelete tools have been removed. Multi-agent coordination is now done entirely through the Agent tool's name parameter — no separate team-creation step is needed.
Before (v2.1.177):
// 1. Call TeamCreate to set up the team
// 2. Call Agent with team_name + name to spawn a teammate
// 3. Call TeamDelete when done
After (v2.1.178):
// Just call Agent with a name parameter
Agent({ name: "researcher", prompt: "..." })
Details
Agent swarms remain gated by the same feature flag as before
The team_name field in TeammateIdle hook events is now deprecated (marked @deprecated) — sessions have a single implicit team; the field will be removed in a future release
System prompt guidance now reads: "If this plan can be broken down into multiple independent tasks, consider spawning named teammates with the Agent tool (pass a name) to parallelize the work."
"main" is now a reserved recipient name for SendMessage — it routes a message directly to the main conversation
Evidence
Removal of TeamCreate/TeamDelete tools (search for "TeamCreate" absent from new file; guidance string search for "spawning named teammates with the"; reserved name message search for "SendMessage routes it to the main conversation")
Strings lifted out of the shipped bundle, so the claim above can be checked against them.
How sure we are
One source agreesOne thing we can check says the same as this entry.
Anthropic's release notes agreeAgent teams: removed the TeamCreate and TeamDelete tools. With CLAUDE_CODE_EXPERIMENTAL_AGENT_TEAMS=1 set, every session now has one…
