Many agent payments involve multiple parties: agent buys on user's behalf, marketplace takes a fee, supplier receives the bulk. AP2 supports multi-party splits but the orchestration is non-trivial.
Split-at-source vs split-after
Split-at-source: payment processor distributes to all parties on capture. Cleaner accounting; requires connected accounts (Stripe Connect, Adyen Marketplaces). Split-after: single capture then transfer; older pattern, more reconciliation burden.
Settlement timing
Funds reach each party at different times: agent's account immediate, marketplace fee next-day, supplier T+2. Cash-flow planning matters; smaller parties need clearer expectations.
Refunds and disputes
Refund-to-source unsplits cleanly if processor supports it. Manual refunds across multiple settlements: messy. Build refund logic before scaling; refunds aren't optional once disputes appear.