Frontier Systems

Prithvi Rajasekaran of Anthropic - Office Hours, Episode 5

This week on Office Hours, Anjney sits down with Prithvi Rajasekaran, a member of Anthropic's labs team and author of a recent post on harness design for long-running coding agents. The conversation ranges across the substance of his post — the generator-evaluator loop borrowed loosely from GANs, the third "planner" agent that complicates the metaphor, the Ralph Wiggum loop, and why context resets unlock Sonnet 4.5 while plain compaction suffices for Opus 4.5 — and into the looser texture of the craft itself: the hours spent reading overnight agent transcripts, the "elicitation overhang" that makes a single prompt feel like a generation of capability, the temptation to over-engineer evals when a senior engineer's intuition would do, and the difficulty of designing async agent UX when waiting thirty minutes raises user expectations to a punishing pitch. Asked what to build, Prithvi's advice to students is to pick the Claude Agent SDK, find a hard problem you actually have, and spend your time in the dev loop where intuition is forged, and his predictions for the rest of the year are of a piece with that posture: models will keep surprising you, long-running agents will become a meaningfully larger share of how we interact with Claude, and the "Claude Code moment" will arrive for domains far outside software, his own recent one having come, somewhat sheepishly, from using Claude as a fitness coach.

Reiner Pope of MatX - Office Hours, Episode 4

This week on Office Hours, Anjney Midha and Mike Abbott are joined by Reiner Pope, CEO and co-founder of MatX, who spent a decade at Google - chip design for neural nets on the TPU team, then writing the inference stack for Palm - before leaving at the end of 2022 to bet that frontier-scale workloads deserved a chip designed from scratch around them. Reiner walks through the architecture decisions behind MatX including why intelligence per picojoule is the eval that matters, how to manage co-design risk when an error on the logic die costs hundreds of billions in CapEx, the trust boundary problem of working with frontier labs whose model architecture is their core IP, and why one well-balanced chip can serve pre-fill, decode, and training rather than splintering into specialized SKUs. He also gets into the parts of the job nobody talks about such as scaling supply chain from zero to gigawatts, fitting inside NVIDIA's de facto rack standard while Google's vertical integration runs ahead, and where SRAM stops scaling once context windows pass a million tokens.

Anastasios Angelopoulos of Arena - Office Hours, Episode 3

In this "Office Hours" episode, Arena co-founder and CEO Dr. Anastasios Angelopoulos discusses how a Berkeley side project became the gold-standard evaluation platform used by every frontier lab. He explains that benchmarks fundamentally cannot capture post-deployment reality, and what happens when a model meets tens of millions of real users doing real work across coding, creative writing, image editing, and increasingly agentic tasks. Angelopoulos argues Arena is structurally ungameable because the question distribution is constantly refreshed by new users, and shares the origin story of NanoBanana - Google's stealth image model whose viral run on Arena marked the first moment the Gemini app inflected globally with consumers. He unpacks the safety-versus-steerability tradeoff in rankings (suggesting LLMs may eventually need movie-style ratings) and why neutrality is not just ethics but the economic foundation of Arena's business. Looking ahead, he predicts long-running agents will become the central unit of work, fundamentally changing what reliability means.

Amanda Askell of Anthropic - Office Hours, Episode 2

In this "Office Hours" episode, Anthropic's Amanda Askell discusses her work making Claude "good"—a journey that took her from a philosophy PhD in formal ethics and decision theory to leading character and alignment work at Anthropic. She explains why Aristotelian virtue ethics has proven more practically useful than abstract theoretical frameworks, and unpacks Anthropic's constitutional approach to AI. Rather than imposing strict rules, the constitution describes situations, values, and good judgment, aiming for coherence across domains so models generalize well into new contexts. Askell argues this approach is safer than the "purely corrigible tool" model, which she worries could generalize into an entity willing to do anything it's told, and stresses the importance of flexibility paired with backbone - models that adapt to users but push back when something genuinely harms them. Looking ahead, she sees the next one to two years as critical as models become more autonomous, and hopes for a "rocky but ultimately good" transition with responsible deployment, strong alignment work, and a society that adapts to the disruption. She closes on an optimistic note about meaning beyond work, drawing on Star Trek-style abundance and the idea that purpose comes from relationships and contribution.

Anjney Midha and Mike Abbott - Office Hours, Episode 1

In this inaugural "Office Hours" livestream, Anjney Midha and Mike Abbott field rapid-fire student questions covering the AI compute and infrastructure landscape. They discuss how scaling laws continue to hold in verifiable domains like coding, materials science, and robotics, while creative writing remains stubbornly hard—an area Anjney would love to see students attack with carefully curated data sets. On infrastructure, they argue that meaningful frontier research now requires clusters in the 4K-16K chip range, that the training/inference distinction is dissolving into one fungible compute pool, and that GPU price corrections will come through standardization and a "universal kernel" abstraction. The conversation closes with leadership lessons from Mike's time at Apple, GM, and Twitter—culture and fiscal discipline are one-way doors you cannot recover once broken—and an extended metaphor about company-building as a road trip where mission alignment determines whether your passengers tolerate the scenic detours. They wrap with a peek at AMP's "grid" scheduling system, which targets Google-level node utilization (95%+) across a multi-cloud portfolio.