What
Before falling back to running a teammate agent in its own git worktree, Claude Code now consults an eligibility helper first and only then takes a new fallback path. The existing refusal, that in-process teammates cannot spawn background agents, is unchanged; what is new is a gate deciding whether worktree isolation is offered at all.
Details
- The helper is the renamed successor of the previous check, and what makes a session eligible is decided inside it rather than at this call site.
Evidence
In-process teammates cannot spawn background agents
Strings lifted out of the shipped bundle, so the claim above can be checked against them.