Introducing Max in Agent Arena
Today, we are releasing our newest version of Max, Arena’s agentic router that achieves frontier performance in Agent Arena with 37% cost savings compared to top models.
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Product
Arena Team—12 Oct 2026
Measuring the AI Frontier for Real-World Alignment: Arena's $200 Million Series B
Arena announces a $200 million Series B at a $3.1 billion valuation to advance real-world AI evaluation. Alongside this milestone, we're introducing the Arena Alignment Index, a new measurement of how well frontier AI models act in line with human intent.
News
Arena Team—8 Oct 2026
Arena Alignment Index
Today we are introducing the Arena Alignment Index, comparing 27 models across 90,000 real-world agent sessions. GPT-6.1 Sol, Claude Opus 5.5, and Grok 4.7 are among the highest-scoring models, with alignment improving across generations. Yet even frontier models still fail in consequential ways, from deleting files without permission to claiming checks they never performed.
Research
Arena Team—8 Oct 2026
How to Post-Train Text-to-Image Models: Combining Preference and Rubric Rewards
We introduce a post-training approach that combines human preference signals with explicit rubric-based rewards. Trained on 5M Arena pairwise preference votes, it pushes FLUX.2-dev to #2 on the live T2I leaderboard and Ideogram 4 past every publicly listed open-source model.
Research
Arena Team—2 Oct 2026
Self-Preference of AI Judges
LLM judges prefer their own responses 70% more often than humans do.
Research
Arena Team—30 Sept 2026
HarnessTax: How Much Does the Harness Matter for Coding Agents?
We tested 21 coding agent model–harness combinations across Claude Code, Codex CLI, and Pi to understand how harness choice affects performance and cost. The results show that harness choice can significantly impact cost, even when task success rates are similar.
Research
Arena Team—16 Sept 2026
Call for Proposals: Arena's Academic Partnerships Program, Fall 2026
Arena's Academic Partnerships Program opens a call for research proposals twice a year, every Spring and Fall. We're excited to open the Fall 2026 cycle today, with submissions due October 30, 2026.
Arena Team—1 Sept 2026
Announcing the First Cohort of Arena's Academic Partnerships Program
We're glad to introduce the first cohort of researchers supported through the Arena Academic Partnerships program.
Arena Team—1 Sept 2026
Coding in Agent Mode: From Idea to Shipping with GitHub
AI coding assistants have fundamentally changed how code is created. But for most developers, a chat interface has been a "read-only" or "copy-paste" coding experience — until now.
Product
Arena Team—24 Aug 2026
Agent Leaderboard Improvements: Categories & Task Cost
Agents are being asked to do a wide variety of work. This means a single, performance-only agentic leaderboard is no longer sufficient. Two questions decide which model to use: what’s best for my specific kind of task, and what will it cost to get that task done? We aim to help answer these questions with our latest update to Agent Arena.
Product
Arena Team—14 Aug 2026
Introducing AutoEval to the Arena leaderboards
At Arena, our evaluations are dynamic and grounded in real-world use. But real-world signals take time to collect. Today, we’re introducing AutoEval scores to provide immediate, calibrated model ratings on real tasks when waiting for human votes to accumulate.
Product
Arena Team—30 Jul 2026
Factuality in the Arena
Factuality remains one of the most persistent questions users face when using AI models. Today, we are launching a leaderboard that ranks models not only by human preference, but also by the factual accuracy of their responses.
Research
Product
Arena Team—14 Jul 2026
Build, Deploy, and Evaluate with Fullstack Code Arena
Code Arena has evolved beyond frontend prototyping into a complete fullstack AI development platform. Explore capabilities like databases, authentication, third-party integrations, and deployments, and see how Fullstack Code Arena helps developers, entrepreneurs, and AI labs build, deploy, and evaluate production-ready applications.
Product
Arena Team—2 Jul 2026