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Showing posts from January, 2026

Reasonable Doubt

In Your job is to deliver code you have proven to work  Simon Willison writes: As software engineers we ... need to deliver code that works — and we need to include proof that it works as well.  He is coming at this from the perspective of LLM-assisted coding, but most of what he says applies in general. I think this is a reasonable consise summary of his requirements for developers: Manual happy paths: get the system into an initial state, exercise the code, check that it has the desired effect on the state. Manual edge cases: no advice given, just a note that skill here is a sign of a senior engineer.  Automated tests: should demonstrate the change like Manual happy paths  but also fail if the change is reverted.  He notes that, even though LLM tooling can write automated tests, it's humans who are accountable for the code and it's on us to "include evidence that it works as it should." Coincidentally, just the week before I read his post I told one of my...