Opus 5 doesn't use em-dashes in code comments

· #claude-code#llm#sqlite

I’ve been using Opus 5 as my main coding for the last few days 1, and I noticed something odd: the code comments stopped using em-dashes; everything is double hyphens (--) now.

Instead of going off a gut feeling, I decided to actually run some checks. agentsview indexes all my conversations into a SQLite database, so this kind of question is just a query away. Here’s the chart:

Em-dashes vs double hyphens in code comments, per model

Seems pretty clear to me! But you might say “maybe it’s not the model, maybe it’s something else”.

Well actually the cleanest evidence came from a session where I switched from Fable to Opus 5 mid-conversation and didn’t touch anything else. Looking at just that session, Fable produced 11 em-dashes in comments. Opus 5 produced 36 double hyphens. I didn’t touch anything else.

What I find genuinely strange is that this only affects code comments. My chat replies still have just as many em-dashes as ever. So maybe something was tweaked when training for code-generation in particular?

Or keep reading on a related topic:

Eight years of wanting, three months of building with AI For eight years, I’ve wanted a high-quality set of devtools for working with SQLite. Given how important SQLite is to the industry, I’ve long been puzzled that no one has invested in building a really good developer experience for it. A couple of weeks ago, after ~250 hours of effort over three months on evenings, weekends, and vacation days, I finally released syntaqlite (GitHub), fulfilling this long-held wish. And …

  1. I don’t like Opus 5 but I ran out of tokens for Sol, Deepseek raised their prices and Fable is just too slow (and I don’t particuarly like it either!)… ↩︎