New Stanford paper finds that when each person's agent acts alone on a shared resource, the group does worse than 1 agent serving everyone.

A shared budget or calendar is handled better by 1 agent serving everyone than by 1 agent per user, across 5 frontier models.

Each agent does a sensible job for its own user.

Together they overwrite each other, stall as the team grows, and with no channel they collapsed outright in 2 environments.

On a contested token budget, Opus 5 teams captured 30% of the achievable value against 64% for 1 coordinating agent.
Agents invented facts about other users in more than half of Claude team episodes in the group-ordering environment.

Prefer 1 agent holding everyone's constraints, and if you run 1 per user, make reading peers a condition of committing.