FWIW I assume Dylan is alluding to cases like this:[1]
Related: Tamay Besiroglu mentions that Fable often outputs gibberish while solving coding tasks, such as “The morning’s slim-scan fix cured the scan hang” and “this is a latent-drift API-shape wrinkle”, and explains it by saying that it invents codenames while reasoning about the problem. roon says GPT-5.5 has a similar issue.
”One thing I mentioned only in passing in my Fable post is that, for long running tasks, Fable starts to develop its own dialect as its many agents and tasks reinforce themselves and make Claudish language ever more Claudish.
You need to ask it to report out in plain English.
This was after a 9 hour task, and it all makes sense, actually, but takes way too much effort to parse, like reading Shakespearian English.”
Where for any particular case you might be able to retroactively construct a plausible interpretation (even in extreme cases), but in general it strictly hurts how much human oversight is applied to model outputs.
FWIW I assume Dylan is alluding to cases like this:[1]
or this:
Where for any particular case you might be able to retroactively construct a plausible interpretation (even in extreme cases), but in general it strictly hurts how much human oversight is applied to model outputs.
This is even now called out as a tip for prompting Fable in Anthropic’s guide: https://platform.claude.com/docs/en/build-with-claude/prompt-engineering/prompting-claude-fable-5#readability-when-communicating-with-the-user