Google released Gemini 3.1 Pro on February 19, 2026, delivering substantial improvements in reasoning capabilities that placed it at the top of independent AI benchmark leaderboards at launch. The model achieves 77.1% on ARC-AGI-2, a benchmark testing novel logic pattern recognition, and debuted atop the Artificial Analysis Intelligence Index with a score of 57.05. (Google. “Gemini 3.1 Pro: A smarter model for your most complex tasks.” Google Blog, February 19, 2026) (Artificial Analysis. “Artificial Analysis Intelligence Index.” Artificial Analysis, April 2026) As of April 2026, GPT-5.5 has taken the index lead at 60; Gemini 3.1 Pro now sits at 57, tied with Claude Opus 4.7 and GPT-5.4.
What is Gemini 3.1 Pro?
Gemini 3.1 Pro is Google’s upgraded flagship reasoning model, building on the Gemini 3 series architecture released in late 2025. According to Google’s official announcement, it represents “a step forward in core reasoning” and serves as a “smarter, more capable baseline for complex problem-solving.” (Google. “Gemini 3.1 Pro: A smarter model for your most complex tasks.” Google Blog, February 19, 2026)
The model is designed specifically for tasks where simple answers aren’t sufficient. Unlike standard conversational AI that generates quick responses, Gemini 3.1 Pro employs advanced reasoning to break down complex problems, synthesize multiple data sources, and produce nuanced outputs across coding, analysis, and creative applications. (Google. “Gemini 3.1 Pro: A smarter model for your most complex tasks.” Google Blog, February 19, 2026)
How Does Gemini 3.1 Pro Work?
Gemini 3.1 Pro utilizes an enhanced reasoning architecture that processes information through multiple reasoning steps before generating final outputs. While Google hasn’t disclosed full technical specifications, the model demonstrates several distinctive capabilities: (Google. “Gemini 3.1 Pro: A smarter model for your most complex tasks.” Google Blog, February 19, 2026)
Code-based generation: The model can generate website-ready animated SVGs directly from text prompts, maintaining crisp quality at any scale due to their pure code construction rather than pixel-based rendering. This enables significantly smaller file sizes compared to traditional video formats.
Complex system synthesis: Gemini 3.1 Pro bridges gaps between complex APIs and user-friendly designs. In demonstrated applications, the model successfully configured public telemetry streams to build live aerospace dashboards visualizing the International Space Station’s orbit.
Interactive design capabilities: The model codes complex 3D simulations (such as starling murmurations), creating immersive experiences with hand-tracking manipulation and generative audio that responds to visual elements.
Creative coding: Gemini 3.1 Pro translates literary themes into functional code, reasoning through atmospheric tones to design contemporary interfaces that capture the essence of source material.
Google has since expanded the preview with a MEDIUM thinking level and a dedicated custom tools endpoint (gemini-3.1-pro-preview-customtools) for agentic workflows that mix bash with custom tools such as view_file or search_code. Provisioned Throughput is not supported on that endpoint, and Google notes that quality may fluctuate in use cases that do not benefit from such tools. (Google. “Gemini 3.1 Pro.” Google Cloud Vertex AI Documentation, 2026)
Gemini 3.1 Pro Benchmarks
Independent benchmark evaluations position Gemini 3.1 Pro at the forefront of AI reasoning capabilities:
| Benchmark | Gemini 3.1 Pro | Claude Opus 4.7 | GPT-5.5 | Significance |
|---|---|---|---|---|
| Artificial Analysis Intelligence Index | 57 | 57 | 60 | Composite reasoning evaluation (Artificial Analysis. “Artificial Analysis Intelligence Index.” Artificial Analysis, April 2026) |
| ARC-AGI-2 | 77.1% | Not disclosed | Not disclosed | Novel logic pattern recognition (Google. “Gemini 3.1 Pro: A smarter model for your most complex tasks.” Google Blog, February 19, 2026) |
| Terminal-Bench 2.0 | Competitive | Highest score | Strong | Agentic coding evaluation (Anthropic. “Introducing Claude Opus 4.7.” Anthropic News, April 16, 2026) |
| Humanity’s Last Exam | Not disclosed | Leading | Strong | Multidisciplinary reasoning test (Anthropic. “Introducing Claude Opus 4.7.” Anthropic News, April 16, 2026) |
The Artificial Analysis Intelligence Index, which incorporates 10 evaluations including GDPval-AA, Terminal-Bench Hard, SciCode, and GPQA Diamond, ranked Gemini 3.1 Pro Preview first at launch with a score of 57.05, ahead of Claude Opus 4.6 (max) at 53.03 and GPT-5.2 (xhigh) at 51.24. (Artificial Analysis. “Artificial Analysis Intelligence Index.” Artificial Analysis, April 2026) By April 2026, Claude Opus 4.7 (released April 16) had closed that gap to tie Gemini at 57, while GPT-5.5 (released April 23) took the index lead at 60. Claude Fable 5 (released June 9, 2026) leads on coding-specific evaluations including FrontierCode, CursorBench, and ViBench; Anthropic has not published numeric scores on the AA index for it. For a broader look at how models stack up on coding tasks, see AI Code Generation Benchmarks 2026: Which Model Actually Delivers.
How Gemini 3.1 Pro Compares to Claude and GPT
The AI model landscape in early 2026 features intense competition between three major players: Google’s Gemini series, Anthropic’s Claude family, and OpenAI’s GPT models. Each approaches reasoning differently, with distinct strengths and trade-offs.
Gemini 3.1 Pro vs Claude
Anthropic’s Claude Opus 4.6, released February 5, 2026, was Gemini 3.1 Pro’s closest competitor at launch, achieving the highest score on Terminal-Bench 2.0 (agentic coding) and leading on Humanity’s Last Exam. (Anthropic. “Claude Opus 4.6.” Anthropic News, February 5, 2026) Anthropic replaced it with Opus 4.7 on April 16, 2026, improving coding benchmark performance by 13% over 4.6 (Anthropic. “Introducing Claude Opus 4.7.” Anthropic News, April 16, 2026) and adding high-resolution vision support (up to 2,576px / 3.75MP). Opus 4.7 (max effort) tied Gemini 3.1 Pro on the Artificial Analysis Intelligence Index at 57 while retaining the agentic task lead. Anthropic then shipped Opus 4.8, which holds the same $5/$25 per million token pricing as 4.7 and is positioned as Anthropic’s most capable Opus-tier model.
Anthropic launched Claude Fable 5 on June 9, 2026, introducing a new Mythos-class tier above the entire Opus line. Fable 5 is Anthropic’s most capable widely released model, with a 1M-token context window, 128k-token max output, and adaptive thinking always on. It leads among frontier models on FrontierCode (Cognition’s medium-effort coding evaluation), CursorBench, and ViBench, and was the first model to break 90% on a core analytics benchmark. Pricing is $10/$50 per million tokens (input/output), exactly twice Opus 4.8’s rate. (Anthropic. “Introducing Claude Fable 5 and Claude Mythos 5.” Anthropic News, June 9, 2026) Companion model Claude Mythos 5 shares the same underlying architecture with safeguards lifted in select areas; it is restricted to Project Glasswing partners and approved biology researchers with no self-serve access. For a head-to-head cost analysis, see Claude Fable 5 vs Opus 4.8: when the 2x price is worth it and Opus 4.8 vs Opus 4.7: What Changed and What Did Not.
The April 2026 Mythos Preview, which autonomously identified and exploited a 17-year-old FreeBSD RCE vulnerability without human involvement, has been succeeded by Claude Mythos 5. (Anthropic. “Claude Mythos Preview.” Anthropic Security Research, April 7, 2026)
Key differentiators for the Claude family versus Gemini 3.1 Pro include:
- Context window: All current Claude flagship models maintain a 1 million token context window, enabling processing of entire codebases and lengthy documents (Anthropic. “Introducing Claude Fable 5 and Claude Mythos 5.” Anthropic News, June 9, 2026)
- Pricing: Opus 4.8 at $5/$25 per million tokens; Fable 5 at $10/$50 per million tokens (input/output) (Anthropic. “Introducing Claude Fable 5 and Claude Mythos 5.” Anthropic News, June 9, 2026)
- Computer use: Claude models pioneered general-purpose computer use capabilities in October 2024, with Sonnet 4.6 showing continued improvement on OSWorld benchmarks (Anthropic. “Introducing Sonnet 4.6.” Anthropic News, February 17, 2026)
- Safety focus: Anthropic emphasizes safety evaluations; Fable 5 ships with cybersecurity classifiers that blocked all 30 jailbreak techniques Anthropic tested, and bio/chemistry prompts fall back to Opus 4.8 (Anthropic. “Introducing Claude Fable 5 and Claude Mythos 5.” Anthropic News, June 9, 2026)
Google counters with Gemini 3.1 Pro’s superior ARC-AGI-2 performance and broader availability across consumer and enterprise platforms without requiring an Ultra subscription tier for basic access.
Gemini 3.1 Pro vs GPT-5.5
OpenAI shipped GPT-5.5 on April 23, 2026, the first fully retrained GPT-5 base since GPT-4.5, ending a run of post-training iterations from 5.1 through 5.4. It now leads the Artificial Analysis Intelligence Index at 60, three points ahead of Gemini 3.1 Pro. (OpenAI. “Introducing GPT-5.5.” OpenAI, April 23, 2026)
| Feature | Gemini 3.1 Pro | GPT-5.5 | Claude Opus 4.8 | Claude Fable 5 |
|---|---|---|---|---|
| Input pricing (per 1M tokens) | Varies by tier | $5.00 | $5.00 | $10.00 |
| Output pricing (per 1M tokens) | Varies by tier | $30.00 | $25.00 | $50.00 |
| Reasoning approach | Integrated | Configurable effort | Extended thinking | Adaptive thinking (always on) |
| API availability | Preview | General | General | General |
GPT-5.5 offers configurable reasoning effort and a 1M-token context window, matching Claude Opus 4.8 on the latter. (OpenAI. “Reasoning models.” OpenAI API Documentation, 2026) OpenAI made the model available in the API on April 24, 2026, roughly doubling per-token pricing from GPT-5.4’s $2.50/$15 to $5/$30 per million tokens; input now matches Claude Opus 4.8, output runs $5 higher. (OpenAI. “Pricing.” OpenAI API Documentation, 2026) With Claude Fable 5 entering at $10/$50 per million tokens as the new performance ceiling, the frontier now spans a wider price range than it did at Gemini 3.1 Pro’s launch. Gemini 3.1 Pro retains its ARC-AGI-2 advantage and a lower price point, but GPT-5.5’s three-point margin on the AA index and Fable 5’s coding-task leads signal that the gap between Google and its rivals has widened since February 2026.
Availability and Access
Google is rolling out Gemini 3.1 Pro across multiple platforms simultaneously: (Google. “Gemini 3.1 Pro: A smarter model for your most complex tasks.” Google Blog, February 19, 2026)
Developers can access the preview through:
- Gemini API in Google AI Studio
- Gemini CLI (command-line interface)
- Google Antigravity (agentic development platform)
- Android Studio integration
Enterprises receive access via:
- Vertex AI
- Gemini Enterprise
Consumers can use 3.1 Pro through:
- Gemini app (with higher limits for Pro and Ultra subscribers)
- NotebookLM (Pro and Ultra exclusive)
This broad availability contrasts with Anthropic’s tiered approach and OpenAI’s model-specific access patterns, potentially accelerating developer adoption.
As of June 2026, Gemini 3.1 Pro remains in preview four months after launch with no confirmed GA date. Google’s model pages list Gemini 3.5 Pro as “coming soon,” suggesting the preview period for 3.1 Pro may close when the next generation arrives rather than through a separate GA milestone. (Google. “Gemini 3.1 Pro.” DeepMind, 2026)
Why Gemini 3.1 Pro Matters
The release of Gemini 3.1 Pro signals several important trends in AI development:
Reasoning as a differentiator: As base model capabilities converge, reasoning quality (measured by benchmarks like ARC-AGI-2 and Humanity’s Last Exam) increasingly determines model selection for complex enterprise workflows.
Multimodal reasoning advancement: Gemini 3.1 Pro’s ability to generate functional code from creative prompts, build interactive visualizations, and synthesize complex data streams demonstrates that reasoning extends beyond text into creative and technical domains.
Competitive pressure accelerates innovation: The 3.1 designation, rather than a full version bump, suggests Google can iterate rapidly on its Gemini 3 architecture, potentially shortening the feedback loop between research breakthroughs and production deployment.
Enterprise integration strategy: By simultaneously releasing across consumer, developer, and enterprise channels, Google signals its intent to make Gemini the default AI infrastructure across Google’s ecosystem.
Frequently Asked Questions
Q: What makes Gemini 3.1 Pro different from Gemini 3 Pro? A: Gemini 3.1 Pro achieves more than double the reasoning performance on ARC-AGI-2 (77.1% vs. approximately 35% for 3 Pro) and leads independent benchmark rankings at launch, making it specifically designed for complex problem-solving tasks where simpler models fail. (Google. “Gemini 3.1 Pro: A smarter model for your most complex tasks.” Google Blog, February 19, 2026)
Q: Is Gemini 3.1 Pro free to use? A: Access varies by tier. The model is available to all users through the Gemini app with standard rate limits, while Pro and Ultra subscribers receive higher usage limits. Developer API access is currently in preview through Google AI Studio and Vertex AI.
Q: How does Gemini 3.1 Pro compare to OpenAI’s o3 models? A: At launch in February 2026, Gemini 3.1 Pro ranked ahead of o3 on the Artificial Analysis Intelligence Index. OpenAI has since shipped GPT-5.4 (March 2026) and GPT-5.5 (April 2026), with GPT-5.5 now leading the index at 60. The o3 series is no longer the relevant OpenAI comparison point.
Q: Can Gemini 3.1 Pro be used for coding? A: Yes. Google specifically highlights code-based animation generation, complex system synthesis, and interactive design capabilities. The model is integrated into Gemini CLI and Android Studio for developer workflows.
Q: When will Gemini 3.1 Pro be generally available? A: Google released 3.1 Pro in preview on February 19, 2026. As of June 2026, the model remains in preview, four months after launch with no confirmed GA date. Google has cited completion of agentic workflow improvements as a prerequisite for general availability. (Google. “Gemini 3.1 Pro: A smarter model for your most complex tasks.” Google Blog, February 19, 2026)
Sources:
- Anthropic Release Notes - April 2026
- Introducing Claude Opus 4.7
- Anthropic rolls out Claude Opus 4.7
- Claude Mythos Preview - Anthropic Security Research
- LLM Leaderboard - Artificial Analysis
- OpenAI announces GPT-5.5
- Introducing GPT-5.5 - OpenAI
- GPT-5.4 features and pricing
- Gemini 3.1 Pro GA status
Sources:
- GPT-5.4 (xhigh) - Intelligence, Performance & Price Analysis
- Artificial Analysis Intelligence Index
- OpenAI’s GPT-5.5 is the new leading AI model
- Anthropic rolls out Claude Opus 4.7, an AI model that is less risky than Mythos
- Claude Mythos Preview - red.anthropic.com
- GPT-5.5 Pricing: Full Breakdown of API, Codex, and ChatGPT Costs
