The Archive

Boris Cherny outlines Anthropic's production guardrails for Claude-generated code: linting, testing, fuzzers, automated review, and refactoring.

Claude Opus 5 achieves lowest prompt injection vulnerability rate across evals and red team testing, per Anthropic's system card.

After working with Opus 4.7 for over two weeks, I noticed a subtle but persistent change in long conversations: the model's fundamental capabilities are still there, but the output feels filtered through something. Details that should be remembered get dropped, consistency drifts. It feels more like the model is zoning out. The system card data seems to support this. MRCR v2 8-needle test: Opus 4.6 scored 91.9% recall at 256k context. Opus 4.7 dropped to 59.2%. At 1M context, it went from 78.3% to 32.2%. That's a significant decline. Boris Cherny has publicly stated that MRCR is being phase...

Boris Cherny, creator of Claude Code, discusses loops as a future direction in a podcast appearance.

Boris Cherny published post-mortem report on Claude Code issues and system design.

Earlier this month, millions of OpenClaw users woke up to a sweeping mandate: The viral AI agent tool, which this year took the worldwide tech industry by storm, had been severely restricted by Anthropic. Anthropic, like other leading AI labs, was under immense pressure to lessen the strain on its systems and start turning a profit. So if the users wanted its Claude AI to power their popular agents, they'd have to start paying handsomely for the privilege. "Our subscriptions weren't built for the usage patterns of these third-party tools," wrote Boris Cherny, head of Claude Code, on X. "We wa...

When the creator of the world's most advanced coding agent speaks, Silicon Valley doesn't just listen — it takes notes. For the past week, the engineering community has been dissecting a thread on X from Boris Cherny, the creator and head of Claude Code at Anthropic. What began as a casual sharing of his personal terminal setup has spiraled into a viral manifesto on the future of software development, with industry insiders calling it a watershed moment for the startup. "If you're not reading the Claude Code best practices straight from its creator, you're behind as a programmer," wrote Jeff ...