a mystery “model 2” is mentioned alongside mythos/fable.

merksittich an hour ago | parent | next [-]

> Model 2, which is somewhat more capable than Mythos 5. Our rough qualitative sense is that this model is a noticeable improvement on Mythos 5 for many tasks relevant to internal use but does not display a capability jump of the degree observed from Claude Opus 4.6 to Mythos Preview. We do not currently have plans to release this model externally, and have not run all of our typical suite of predeployment assessments, so we have somewhat lower confidence in our beliefs about its capabilities.

	▲	andai an hour ago \| parent [-]
		"Yeah, you wouldn't know her, she goes to another school."

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lwarfield an hour ago | parent | prev | next [-]

> More capable than Mythos 5 in some areas, less capable in others; overall slightly more capable.

This sounds like it might be a Mythos finetune for some specific task.

EDIT: After reading some more reading, it looks like model 2 might be an AI research fine tune based off the section 3.4.3 CoBench

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flyinglizard an hour ago | parent | prev [-]

Meanwhile I can't really tell the difference between Fable and Opus for my tasks. I kinda think Fable does a better UX work so I keep using it for that because I couldn't be bothered to A/B them, but otherwise it's all the same and the model and effort are just feel good knobs I twist to still remain a load-bearing element. At least that's my honest take.

	▲	dataminded an hour ago \| parent \| next [-]
		Fable was amazing during the first preview. Once they added it back, the limits are too low to get anything done. I might use it in chat if I remember to select it once a month but don’t even bother to try and code with it.
	▲	malexw an hour ago \| parent \| prev [-]
		For the past 2 weeks or so I've been doing the A/B test, sending identical prompts to Fable 5 and Opus 5 to test their ability to produce design documents for new feature work. I've consistently found that Opus 5 produces more complete, accurate and "imaginative" designs than Fable, often finding design issues or nearby bugs that Fable 5 misses. However, that creativity means Opus seems to hallucinate more, while Fable's design is clearly based on the actual existing code. Or as Opus put it: "I hedged — [Fable] checked." By pitting them against each other I get much better design work, and then I've been happy to hand off the design file to Opus 5 for implementation. But some of the assumptions Opus 5 makes leaves me wary of relying on it too strongly. This might be fixable by prompting it to ground its answers.