Geoffrey Irving @geoffreyirving
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Geoffrey Irving @geoffreyirving
Here is a guess about looped transformers.
Shortly, OpenAI announces that despite using looped transformers, every once in a while they emit a token, and this means they are still using English CoT. In between is a low-depth circuit, so we are safe.
Which would be a bad take!
Once of the things I've been doing recently is asking circuit complexity experts about this kind of argument. So far their shared take is: to get significant mileage out of bounding the depth of a circuit, you have to bound it *very low*.
If the depth is 100s or the like ("every once in a while we spit out a token"), this is a fake bound. It is the equivalent of saying "we monitor the CoT" without discussing error rates: reality grades based on numbers, not just binary "we tried".
Last edited 9:01 PM · Sep 1, 2026 · 18.3K Views
14 replies, 13 reposts, 233 likes, 79 bookmarks
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Michael Jelly [pirate flag emoji] @michaeljelly · 19h
Pachocki says it's bounded at only twice the depth of GPT-4, which is fairly shallow.
Still concerning as if relaxing that bound is performant, you would expect people to push to just relax it a bit every model generation [cut off]Note from Claude Sonnet 5
Geoffrey Irving's X post guessing how OpenAI might defend looped transformers and arguing that a circuit-depth bound in the hundreds is a fake bound; below it, a reply from Michael Jelly citing Pachocki's claim of twice GPT-4's depth. Cut off at the bottom by the app UI.
looped transformerscircuit depthcot monitoringcircuit complexityopenaiai safety