Boris Cherny’s line—“I don’t prompt Claude anymore. I have loops running that prompt Claude and figure out what to do”—captures a shift in coding practice. Instead of single-shot prompts, people now build harnesses that queue tasks, run an LLM (like Claude), inspect its output, then decide to continue the session, tweak context, or hand it off. That outer loop extends the model’s life beyond a single response. Armin Ronacher finds this powerful in theory but hasn’t trusted it for code he deeply cares about. Off-the-shelf loops churn out defensive, overly complex code, duplicating logic, papering over design flaws with extra checks instead of enforcing clear invariants. Models “terrified of exceptions” tend to tack on local fallbacks rather than eliminate impossible states. Each cycle in a hands-off loop adds another layer of defensive plumbing. That makes the system look robust at first glance but gradually erodes readability and correctness. Junior developers using these loops can end up with sprawling codebases they can’t justify—because the LLM will always invent a plausible rationale for every extra branch or fallback. Still, loops shine in niche domains. Ronacher points to large-scale porting projects—Zig-to-Rust migrations for Bun or his own MiniJinja-to-Go experiments—where transforming existing code works like a charm. Performance tuning, security audits and other explorations fit too: the loop runs benchmarks, filters failures, surfaces insights, and throws away throwaway code. Here the harness either verifies mechanically or even leans on a second LLM as a judge. The judge needn’t be perfect—just consistent enough to drive a new iteration. He draws a line between throwaway artifacts and lasting code. For experiments, the organism-style loop feels liberating. But for production systems, he still values machines you can “peel” like a black box, deterministic behavior you can map end to end. LLM-driven loops push software toward living, unpredictable systems—an appealing research path, but not yet where he trusts mission-critical code to live.