Arena.ai
@arena • 234,612 subscribers
Where AI meets the real world. We measure and advance the frontier of AI through community-driven evaluation. We’re hiring → https://t.co/XBZCrsdD77
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Today, we're announcing our Series B: $200M at a $3.1B valuation, and the release of Arena's Alignment Index. AI is advancing faster than our ability to evaluate it. The world needs a neutral third party to measure how safe and aligned AI actually is once it's in the hands of real people. That's the role Arena is stepping into today. The Alignment Index is built from real-world agent traces, starting with three signals: Unauthorized Action, False Attribution, and Deceptive Completion, with results for over 20 frontier models launching today. Hear more from our CEO Anastasios Nikolas Angelopoulos below, and read the full breakdown, and more details about our company growth in thread. This funding will allow us to go further on safety signals, agentic capabilities, and modalities. It will also allow us to grow the company to match the scale of our mission. Today, we’re still a nimble team of 90, and we're looking for people to join us across research, product, engineering, and more. Come build with us. As AI gets more capable and autonomous, understanding how well it can safely and effectively work for people only matters more. That's what Arena is built to measure and advance. Thank you to our community, our investors, and everyone building with us! Take a look at our open roles if you want to join us (link in bio).
Arena.ai114,531 görüntüleme • 9 gün önce
Check out side-by-side outputs generated on Arena from Claude Opus 5.5 by Anthropic and GPT-6 Sol by OpenAI. Scores for Claude Opus 5.5 are coming soon. Real-world tasks from our global community of users power the Arena leaderboards. Head to Arena now to test it out, and stay tuned!
Arena.ai148,055 görüntüleme • 24 gün önce
Claude Code vs Codex vs Pi: which coding agent wins? Melissa Pan, PhD candidate at UC Berkeley’s Sky Computing Lab and previous Arena.ai intern, explored the hidden “harness tax”: how the system surrounding an AI model affects its cost and performance. She reports three surprising findings. One: harness choice impacts cost more than accuracy. To learn about all three findings, and what they mean for building useful coding agents on realistic budgets, check out the full video here:
Arena.ai85,347 görüntüleme • 19 gün önce
Introducing Agent Mode: Agentic AI is now measured in the Arena. Agent Mode can do deep research, create reports, generate images, build websites, debug code, and more. It completes more complex tasks by using tools like web search, bash in a sandbox environment, image generation, file writing, and asking follow-up questions. Frontier models are waiting for you in Agent Mode to take on real-world tasks. GPT-5.5, Claude Opus 4.7, Gemini 3.1 Pro, and top open models. Test them yourself.
Arena.ai550,664 görüntüleme • 4 ay önce
Code Arena just leveled up with fullstack capabilities 🚀 Introducing the new Fullstack Code Arena. We’re moving beyond frontend prototypes to fullstack development complete with databases, API keys, and fast deployments. Build, iterate, and ship real-world software — all in one place. Models now act as agents in the Code Arena, using structured tool calls to plan, execute, and refine in real time with real world tasks. Read more about it in the thread 🧵
Arena.ai288,910 görüntüleme • 3 ay önce
Arena reached a $100M annual revenue run rate just 8 months after launching our evaluation product. We started as a research project at UC Berkeley with a simple mission: measure AI progress through real-world use. As AI shifts from chatbots to agents taking on longer, higher-stakes work, the problem matters more than ever. Today, Arena measures real-world AI utility with a community of tens of millions. With Agent Arena, we’re evaluating long-running agents on complex, real-world tasks - how they use tools, adapt to feedback, recover from errors, and accomplish goals set by humans. We are excited to keep deepening our work in agentic evaluations. Here’s Anastasios Nikolas Angelopoulos on what this milestone means and where we go from here:
Arena.ai213,143 görüntüleme • 3 ay önce
📢We’re excited to share that we’ve raised $100M in seed funding to support LMArena and continue our research on reliable AI. Led by a16z and UC Investments (University of California), we're proud to have the support of those that believe in both the science and the mission. We’re focused on building a neutral, open, community-driven platform that helps the world understand and improve the performance of AI models on real queries from real users. Also, big news is coming next week!👀 We're relaunching LMArena with a whole new look built directly with community feedback from the ground up 🧱 Link in thread.
Arena.ai436,527 görüntüleme • 1 yıl önce
GPT-5.2-high by OpenAI is off to a strong start in the Code Arena. ⚡️ If you’re new here: Code Arena is where AI models build full web apps, tools, and interactive sites — all from a single prompt. Watch the video to see GPT-5.2-high in action, then try your own prompt and reply with your creation below. ⬇️
Arena.ai246,430 görüntüleme • 10 ay önce
During an agentic session, a quick “hi” after a coffee break can cost a full dollar. But it’s not because of the “hi.” It’s the million tokens of context you’re repaying for the moment your cache goes cold. Here's the caching math from Evan: 0:00 Why you're billed for last turn's context, not just this one 0:17 Cache hits: ~10% of full price 0:41 Agentic AI = way more back-and-forth than chat 1:16 Paying full price for context even on a 1-token tool call 1:40 Cache hit vs. cache miss 2:13 The $1 "hi": walk away for an hour, come back to a cold cache 2:59 Cost grows by the square, even with caching 3:28 How context compaction helps 4:03 Why Claude Code/Codex may compact at ~200-300K, not the full 1M window
Arena.ai53,273 görüntüleme • 2 ay önce
The NEW LMArena is officially live! 🎉 ✨ New Logo! ⚡️ Better, faster UI/UX for chat and leaderboard 📱 Mobile optimized 💬 Chat history 🧭 Clearer leaderboard navigation 🤖 Many modalities in one place: vision, image, and more coming soon Try it now at lmarena dot ai! (Link in 🧵)
Arena.ai267,006 görüntüleme • 1 yıl önce
We put the top three Code Arena models head-to-head: Opus 4.5 Thinking 32k, Opus 4.5, and Gemini 3 Pro. They’re just 20 points apart. Same tough prompts, different results. Here’s what stood out. Remember, your votes drive the rankings. Watch how these contenders move on the leaderboard as more votes come in. Check out the comparisons in the thread below. 🧵
Arena.ai163,929 görüntüleme • 10 ay önce
Meet… Arena Conversations. Peter Gostev sits down with Poolside researchers,Connor Adams and Aalhad Patankar, to discuss how they’re building frontier open coding models. Episode drops today at 10am PT on our YouTube. They dig into Poolside's Laguna model family, why the team publishes full trajectories (not just benchmark scores) for anyone to audit, and how "experiments" at Poolside range from data mixes to harness design to reward-tuning decisions run tens of thousands of times a day.
Arena.ai40,188 görüntüleme • 2 ay önce
Kimi K3 passed Fable 5 on Code Arena just 6 weeks after Fable's release, landing #1 in 6 of 7 frontend domains. We sat down with Arena CEO and co-founder Anastasios Nikolas Angelopoulos for a rapid fire conversation on what the data from real-world use tells us 👇 0:00 Biggest release of the year, or overreaction? 0:33 Kimi K3 beats Fable on Code Arena: verifying the votes 1:35 1679 points: a 17-place jump from K2.6 2:37 #1 in 6 of 7 frontend domains — but still #2 in gaming 3:15 Permanent shift or snapshot? Labs distilling Chinese models 4:23 Regulating Chinese models: the case for and against 6:30 $3 in, $15 out: open source is no longer 10% of the price 7:30 If you're Anthropic or OpenAI, what's your move? 8:09 How long before the leaderboard flips again?
Arena.ai50,961 görüntüleme • 2 ay önce
