Verification now takes far longer than implementation: roughly 85% of time on fixing and validating versus 15% on initial coding.

Jarred Sumner reports that in his Bun rewrite, implementation took about 15% of the effort while 85% went to fixing compile bugs, passing tests, and verifying correctness—a pattern Thariq Shihipar confirms holds broadly at Anthropic. ✦ AI generated

Jarred Sumner · The Pragmatic Engineer · 2026-07-28 · original ↗

Implementation of the Rust rewrite took far less time than fixing it up, then validating that it works as expected. The 'implementation' part of rewriting the code from Zig to Rust took about 15% of the time, while 85% went on fixing things up: getting it to compile, fixing tests, verifying that it worked.

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