[bokelley]

Part of #1669, alongside #1707: the reference seller (examples/seller_agent.py) gaps that #1707's audit found.

AdCP 3.3 rules (migration guide §Delivery rows may omit impressions, §Multi-qualifier metrics omit flat totals):

• Impressions: absent means not measured, never zero. Totals now carry impressions only when a delivery measured them; package rows already followed the totals.
• Rates: never derive an impression-denominated rate without a count. viewable_rate is omitted when nothing was measurable, where it used to be 0.
• Multiple standards: a metric reported under more than one qualifier omits its flat carrier from buy totals. The flat viewability block is omitted when deliveries used more than one standard.
• Callers below 3.3: a dimensional row with no impression count is omitted, not sent with impressions: 0. by_format rows without impressions are dropped for those callers.

Totals and by_package don't require impressions in 3.2 either, so they stay valid for 3.2 callers. Storyboard deliveries always inject impressions, so their responses are unchanged.

Tests: three new cases in tests/test_seller_agent_storyboard.py. That file and test_seller_agent_dual_emit.py: 43 passed.

Refs #1669

🤖 Generated with Claude Code

[aao-secretariat]

Ladon verdict: Approve

Approve.

Clean, well-scoped fix to the reference seller example plus tests (2 files, +77/-4). The reviewer traced all three AdCP 3.3 behaviors (impressions omitted when unmeasured, viewable_rate dropped when measurable == 0, flat viewability block gated on a single standard) and confirmed _serves_impressionless_rows parses version robustly (3.3-beta.1 keep, 3.2 drop, None/malformed fail-open). The DR-0032/0033 droppable pathway for pre-3.3 callers is tested.

No critical/high/medium findings. Not a gated path, high_risk is false, no author team gate, no prior decision. None of rows 1–8 fire, so this falls through to row 9 = approve.