Type: url
Original: https://simonwillison.net/2025/Dec/18/code-proven-to-work/
Status: generated
Summary
A December 18, 2025 post by Simon Willison arguing that a software engineer’s job is to deliver code they have proven to work, and that depositing large untested LLM-generated pull requests on reviewers shifts the real work downstream. It sets out two non-optional steps for proving a change — manual testing, demonstrated to reviewers with pasted terminal output or a screen recording, and an automated test that fails when the implementation is reverted — and argues that mastering coding agents means making them perform both steps as well, with the human retaining accountability.