DHH Lets Claude Rewrite Python Library in Rust in 3 Hours, 11M Tokens, Zero Intervention

新智元 · wechat · 2026-08-15

Rails creator DHH showed off a fully delegated rewrite: he only asked Claude to draft a plan, then stayed hands-off while 8 agents each took a branch to read code, implement, compile, run tests and merge. In 3h11m and roughly 11M tokens, the Python terminal-effects library TerminalTextEffects was rewritten as 21K lines of Rust (new repo ttfx), compiled into a 3MB binary supporting 37 effects — startup dropped from 87ms to 2ms and rendering got 9.6x faster. Codex completed the same task well from a single prompt, just 30% slower at $43 in token costs. Claude Code creator Boris Cherny showed up in the replies calling it awesome.

Notably, DHH has reversed course: in May last year he wrote he'd "rather retire than hand the keyboard to AI," yet now says that within five years few people will still write or read code. The article also cites Bun founder Jarred Sumner's AI-driven migration of a million-line codebase from Zig to Rust in under two weeks, arguing the marginal cost of code generation is heading toward zero and programmers' core value will shift to defining problems, constraints, test suites and judging AI output.

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