we build an automated code review tool, so we get a unique view of how AI-generated code behaves in real workflows across IDEs and models. insights from our 2025 sample. bug rates vary widely across models: 2.7 to 19. 5 bugs per 10k lines (7. 2x spread). 1/9 🧵

Spellchecking did not start as a subtle, always-on feature. The early spell checkers were basically batch programs: take a document, compare tokens against a dictionary, print a list of suspicious words On PCs in the 1980s, spellchecking becomes more mainstream, but it is still mostly a deliberate step. Many systems either shipped as separate utilities or ran in a proofing mode inside word processors that you had to run yourself. What is easy to miss is why it changed. I think that a major leap was not just better detection of mistakes but the innovations to make spell checking fast enough to feel interactive: compressing dictionaries with affix stripping (store stems plus prefix and suffix rules), keeping a frequent word list in (limited!) main memory to avoid slow disk accesses, and using hashed / bitmap based membership tests to quickly answer "is this a word?" without storing the full wordlist verbatim. In other words, once it got fast enough, the interface flipped. Spellcheck moved into the background and became continuous. When the editor can underline mistakes while you type, you stop thinking of it as a separate tool and it becomes part of writing. Microsoft Word made this style mainstream in the mid-1990s, right around the Windows 95 era, when I was coming of age as a young computer nerd. I think automated code review hasn't yet made this shift. It is treated like a batch job, and the latency is high enough that people naturally push it to the end. I wrote a short blog post about what changes when review is fast enough to stay in flow, and why timing matters as much as what a tool finds. That work also enabled a feature we just shipped at kluster.ai: Ambient Background Review in your IDE. It runs continuously and only interrupts when there is actually something worth saying. Like spellcheck in Microsoft Word in 1995. At the risk of sounding like this post is written by AI, I think this is a game changer. Attached picture of the Microsoft Windows 95 manual that is usually on my bookshelf, which I recently found myself flipping through again. kluster.ai/blog/fast-high-qu…