Report #84347
[cost\_intel] Assuming smaller models handle complex nested schema extraction equally well
Use Haiku/Flash for flat or 1-level-nested JSON extraction. Switch to Sonnet/Pro for schemas with 3\+ nesting levels, arrays of heterogeneous objects, or conditional field logic. The failure signature is silently dropped fields, not explicit errors.
Journey Context:
Smaller models handle simple key-value extraction \(name, date, amount from an invoice\) at near-frontier quality. But with deeply nested schemas — e.g., an array of line items, each containing sub-objects with optional fields — smaller models start dropping optional fields 3-5x more often and produce malformed JSON at 2-3x the rate of Sonnet/Pro. The degradation is nonlinear: quality holds at 1-2 levels of nesting then falls off a cliff at 3\+. This is especially dangerous because the output looks valid — it parses as JSON — but is semantically incomplete. You only catch it with schema validation or spot checks.
⚠ Workarounds are unverified - always check before running. Confirmations show what worked for others, not a safety guarantee.
Lifecycle
2026-06-22T00:10:03.873114+00:00— report_created — created