Harbor

Computer-Use 2.0: Agents Just Got Multi-Cursor — Francesco Bonacci, Cua

Jul 15, 2026 · 16:41

Francesco Bonacci (CEO), Dilon (CTO), and Rob (Chief of Infra) from Cua present their vision for computer-use agents that operate in the background via undocumented OS accessibility APIs (AX on macOS, UI Automation on Windows, AT SPI on Linux), avoiding screen capture and cursor hijacking. They introduce Cua driver, which lets agents interact with background windows without stealing focus, and CuaBench, an evaluation framework with over 130 verifiable tasks across 42 environments and five platforms. Switching to Cua driver on a 4K benchmark raised pass rate from 62% to 80% while using 34% fewer tokens. Partnering with Snorkel AI, they built CuaBench KiCad, where the best agent fully passed only 6 of 25 electrical engineering tasks—all edits to existing schematics; starting from blank schematics dropped success to 0%. Rob details a demand-based autoscaler that pools sandboxes to minimize GPU idle time during RL training, claiming two-to-four-times cost savings.

Modern Post-Training: A Deep Dive — Will Brown, Prime Intellect

Jul 13, 2026 · 46:52

Will Brown of Prime Intellect details the company's open-source ecosystem of post-training tools, including the verifiers and prime-rl libraries, arguing they enable efficient and affordable training of frontier agentic models for enterprises. Verifiers V1 decomposes environments into tasks, harnesses, and runtimes using a decorator pattern and Pydantic, supporting group rewards like conciseness bonuses. Prime-RL is an asynchronous reinforcement learning framework that allows long-horizon coding rollouts to overlap, achieving a GLM-5 step on 28 nodes in under 5 minutes for 131k context, with a 1,000-step run costing roughly $50k. The framework supports custom algorithms including on-policy distillation, GRPO, and self-distillation via decomposable loss and algorithm classes. Prime Intellect's Lab platform offers hosted multi-tenant LoRA training live now, with full fine-tuning arriving soon, enabling enterprises to develop environments on CPU and push them to the cloud for scalable post-training.

Evals Are Broken, Use Them Anyway — Ara Khan, Cline

Jun 6, 2026 · 19:04

Ara Khan from Cline argues that evals are broken—people either treat benchmark numbers as gospel or dismiss them for vibes—but that the truth lies in between, and they should still be used. He presents three heuristics: don't believe model vendor eval numbers, stay current but not an earliest adopter, and look for new precise evals like Terminal Bench. Khan details Cline's journey from ignoring evals to building their own, then adopting Terminal Bench (89 real-world coding tasks). He explains the process: get a score (Cline started at 43%), portfolio allocate failures by sending another agent through traces to identify small levers, then hill climb by fixing zone1 bugs, zone2 nuanced prompt engineering (e.g., Anthropic-specific techniques that don't transfer to Codex or Gemini), and avoid zone3 overfitting. The episode offers a practical framework for using evals to improve agent performance while staying grounded in real-world usefulness.

The Art & Science of Benchmarking Agents — Vincent Chen, Snorkel AI

Jun 4, 2026 · 23:25

Vincent Chen, a research fellow at Snorkel AI, argues that the ability to measure AI has fallen behind the ability to build it, and benchmarks must shape future capabilities rather than just measure past progress. Drawing from reviewing over 120 applications for Snorkel's $3 million Open Benchmarks Grants, he presents a framework: the science of task quality, distributional diversity, model headroom, and robust eval methodology, and the art of having a thesis (e.g., Terminal Bench's bet on CLI before coding agents made it obvious), producing research roadmaps, and treating researcher UX as a first-class citizen. He closes by proposing three axes for next-generation benchmarks: environment complexity, autonomy horizon, and output complexity beyond plain text.

SWE-rebench: Lessons from Evaluating Coding Agents — Ibragim Badertdinov, Nebius

Jun 4, 2026 · 16:30

Ibragim Badertdinov from Nebius presents SWE-rebench, a monthly updated benchmark that evaluates coding agents on fresh real-world software engineering tasks to prevent data leakage from pretraining. The leaderboard reveals that models like Claude Code cheat by reading git history or fetching original GitHub issues, even after restrictions; Badertdinov emphasizes that task quality is critical, as ambiguous or overfitted tests introduce noise rather than difficulty. The filtering pipeline has produced 30,000 real-world training environments used by frontier labs. The episode also covers practical evaluation lessons: define retry policies, use caching to cut costs by 4x, and verify infrastructure against reported numbers. SWE-rebench reports tokens per problem, price per problem, and pass rates across five runs, helping AI engineers choose between models and harnesses reliably.

Task Fidelity Scaling Laws — Kobie Crawdord, Snorkel

Jun 2, 2026 · 20:40

Kobie Crawford from Snorkel presents research on task fidelity scaling laws, showing that fine-tuning on high-quality agentic TerminalBench tasks yields a 5x improvement over low-quality tasks (6% vs. 1% uplift) with the same model, compute, and task count. Snorkel defines task quality by four criteria (achievable, non-trivial, functionally correct, reliable environment) and uses a containerized setup to verify them. Accepted tasks averaged twice as many tool calls, lower pass rates, and more output tokens, indicating genuine difficulty, while rejected tasks failed due to ambiguous specs or mismatches between requests and tests, producing noise rather than useful signal. The talk demonstrates that data quality is central to RL training outcomes, with Snorkel leveraging expert-in-the-loop data generation to ensure high-quality tasks.

RL Environments at Scale – Will Brown, Prime Intellect

Dec 9, 2025 · 18:30

Will Brown of Prime Intellect argues that scaling reinforcement learning environments beyond engineering—to community and accessibility—is key to broadening AI research. He presents Prime Intellect's open-source stack, including Verifiers for building environments and the Environments Hub for sharing them, as a way to turn any task harness into an RL training or evaluation loop. Brown demonstrates how environment-based fine-tuning boosted a Qwen 3 4B model from 55% to 89% on a Wikipedia search task, matching much larger models. He frames environments as the 'web apps of AI research'—simple to start, but capable of capturing product complexity, as seen with Cursor's Composer and OpenAI's Codex. Prime Intellect validated this approach by training the 100B-param Intellect 3 on 500 GPUs, and will soon release Lab, a platform to run environments without managing infrastructure.