model-evaluation

Claude Fable 5 and Its Guardrails: A Hands-On Look at What the New Anthropic Model Will and Won't Do

Claude Fable 5 launched to strong impressions and an instant guardrail backlash. Here's what the new Anthropic model does well, where the refusal line falls, and how to evaluate whether it fits real work.

06/11/2026 · Model Evaluation · 7 min read

Claude Fable 5 Review: Capabilities, "Mythos-Class," and the Safety Controversy

Anthropic's Claude Fable 5 is its first "Mythos-class" model, headlined by one-click game generation. But the more durable story is the safety controversy — restricted topics and reports that it may quietly hold back on some tasks.

06/10/2026 · Model Evaluation · 8 min read

Claude Fable 5 Explained: What "Mythos-Class" Means and How to Evaluate It

Anthropic shipped Claude Fable 5, its most powerful public model yet — days after warning that AI is getting too dangerous. Here's what "Mythos-class" signals and how to evaluate Fable 5 for real agent work instead of taking the launch at face value.

06/09/2026 · Model Evaluation · 8 min read

Agentic RL Explained: What OpenEnv Means for Training AI Agents

Agentic RL trains AI agents by letting them act in environments and learn from outcomes. OpenEnv, backed by Hugging Face, PyTorch, Nvidia and more, gives open source the shared training substrate frontier labs already had.

06/09/2026 · Research · 10 min read

Computer Use Agent Benchmarks, Explained: What They Measure and How to Read One

A computer use agent benchmark tells you whether an OS-driving agent actually works — but only if you know what it measures. Here's how to read task success, trajectory quality, and cost before you trust the headline number.

06/09/2026 · Model Evaluation · 11 min read

Computer-Use Agents in 2026: How Good They Are and How to Run One Locally

Computer-use agents have moved past demos — Holo3.1 ships local checkpoints and the new MacArena benchmark exposes where they still break. Here's how good computer-use agents really are in 2026 and how to run one locally.

06/08/2026 · Model Evaluation · 8 min read