01 · Operational consequence
Lifecycleactive
Severityhigh
ConsequenceThe documented behavior applies to these Gemini API models and future model releases; no regional exception is listed.
02 · Affected subjects
ComponentsGemini 3.7 Flash and other Gemini 3.x requests using deprecated sampling controls or prefilled model turns
AudienceGemini API developers migrating to Gemini 3.7 Flash or other current Gemini 3.x models with sampling overrides or prefilled model turns.
RegionGemini API behavior for affected models
03 · Detection
Stable event IDksr-google-gemini-sampling-turns-2026
Change typebreaking_api_change
04 · Before → after
BeforeEarlier request patterns accepted
AfterAffected request patterns return HTTP 400
05 · Required action
ActionRemove deprecated sampling parameters and prefilled model turns; use thinking_level and previous_interaction_id where appropriate; add regression tests for HTTP 400 failures.
Replacement or migration pathStrip temperature, top_p, top_k and candidate_count; replace thinking_budget with thinking_level; remove prefilled model turns and standardize multi-turn state on previous_interaction_id.
06 · Actionable date
Date roleEffective date
Date2026-07-21
Statusactive
07 · Kingy reproduction
StatusNot tested
LimitationsSource evidence reviewed; no paid vendor call or production reproduction was run.
08 · Sources and revision
Checked2026-09-04
Official sourceshttps://ai.google.dev/gemini-api/docs/latest-model · https://ai.google.dev/gemini-api/docs/changelog · https://ai.google.dev/gemini-api/docs/pricing
Correction history2026-08-23: Refreshed affected models and migration instructions for the Gemini 3.7 Flash GA release.