Assign multiple members to card

Assign Emily and Carlos to the card 'Client onboarding: Phase 1' so both see notifications and can be scheduled. Add a short comment assigning roles: Emily for documentation, Carlos for client calls. Verify that both are already members of the board and add them if not.

Before I add multiple assignees to this onboarding card, make it obvious who does what: state primary owner, list two responsibilities for each additional member, and add a checklist with the tasks split between them. Flag any handoff points that could cause missed customer deadlines.

I put Emily and Carlos on 'Client onboarding: Phase 1' but they both think they're primary. The kickoff is tomorrow. How should I set roles and an escalation path in one message so responsibilities are clear and nothing slips for the client?

Across projects we tag multiple members on a card and tasks fall through the cracks because no single person feels accountable. What naming convention or micro-habit will restore clarity and ensure one person is ultimately responsible? Recommend a single rule to apply to all cards.