Evaluator: create_media_buy test payload missing buyer_ref field

[tescoboy]

Summary

The evaluate_agent_quality evaluator does not include buyer_ref in the create_media_buy tool call payload, causing validation errors on any seller agent that correctly requires this field.

Expected Behavior

The evaluator should include buyer_ref at both levels when calling create_media_buy:

• Top-level request: buyer_ref (string, buyer's reference for the media buy)
• Per-package: packages[].buyer_ref (string, buyer's reference for each package)

Per the AdCP spec, buyer_ref is the buyer's own reference identifier used for idempotency and reconciliation. Seller agents that enforce this as required (which is correct behavior) will reject the evaluator's test calls.

Actual Behavior

The evaluator sends:

{
  "brand": {"domain": "test.example.com"},
  "start_time": "2026-05-01T00:00:00Z",
  "end_time": "2026-05-31T00:00:00Z",
  "packages": [{
    "product_id": "...",
    "pricing_option_id": "...",
    "budget": 1000
  }]
}

No buyer_ref at the top level or package level.

Impact

• create_media_buy scenario fails
• full_sales_flow scenario fails
• creative_inline scenario fails

Fix

Add buyer_ref to the evaluator's create_media_buy test payload at both the top level and inside each package.

[bokelley]

Thanks for the report. Can you confirm which version of the AdCP spec your agent is built against?

buyer_ref was removed in v3 (rc.3) and replaced with idempotency_key — an optional field for request deduplication. The current evaluator builds payloads against the rc.3 schema, which no longer includes buyer_ref.

If your agent requires buyer_ref, it's likely validating against the rc.2 schema. The v3 readiness checklist covers this migration: https://adcontextprotocol.org/docs/reference/migration/v3-readiness

Let us know and we can help with the upgrade path.