What changed
gemini-3.8-flash replaces gemini-3.7-flash as Google's recommended Flash model — same 1M context / 65,536 output tokens / multimodal inputs (text, image, audio, video, PDF), but with improved reasoning via smaller iterative steps plus tool-calling loops, and a new thinking_level enum (LOW / MEDIUM / HIGH) replacing the reasoning_budget integer. DeepSWE v1.1 score climbs from 65.3% (3.7 Flash) to 73.7% (3.8 Flash). Introductory pricing through December 31, 2026: $0.75/$3.75 per 1M input/output tokens; standard pricing ($1.50/$7.50) takes effect January 1, 2027.
TL;DR
Gemini 3.8 Flash scores 73.7% on DeepSWE v1.1 (long-horizon agentic coding), adds a thinking_level: LOW | MEDIUM | HIGH enum replacing reasoning_budget, and is available now in AI Studio and the Gemini API at $0.75/$3.75 per MTok intro rate.
Developer signal
Two things to act on: (1) If your Gemini API code uses reasoning_budget (the integer), switch to thinking_level: "medium" for equivalent behavior — the integer parameter is not supported on 3.8 Flash. Google set MEDIUM as the default, which provides the best quality/cost tradeoff for most tasks; set LOW for latency-critical pipelines (incident response, real-time chat) or HIGH only where maximum accuracy is required (dense visual QA, multi-step legal/financial reasoning). (2) If you're using gemini-flash-latest or another versionless alias, verify which model it resolves to — aliases may start pointing to 3.8 Flash. If your pipeline was tuned for 3.7 Flash token counts, 3.8 Flash with MEDIUM thinking will use more output tokens (thinking tokens bill as output tokens). A separate cybersecurity variant, Gemini 3.8 Flash Cyber, ships simultaneously — not public API, restricted to Fairwind Program trusted defenders (government authorities, critical infrastructure operators, open source maintainers; application-based access, not self-serve). Flash Cyber benchmarks: >70% on Google's internal real-world vulnerability benchmark across 20 languages, 47.2% pass@1 on CWE-Bench patching.