> Importantly, we find that when used in an interactive, synchronous, “hands-on-keyboard” pattern, the benefits of the model were less clear. When used in this fashion, some users perceived Mythos Preview as too slow and did not realize as much value. Autonomous, long-running agent harnesses better elicited the model’s coding capabilities. (p201)

^^ From the surrounding context, this could just be because the model tends to do a lot of work in the background which naturally takes time.

> Terminal-Bench 2.0 timeouts get quite restrictive at times, especially with thinking models, which risks hiding real capabilities jumps behind seemingly uncorrelated confounders like sampling speed. Moreover, some Terminal-Bench 2.0 tasks have ambiguities and limited resource specs that don’t properly allow agents to explore the full solution space — both being currently addressed by the maintainers in the 2.1 update. To exclusively measure agentic coding capabilities net of the confounders, we also ran Terminal-Bench with the latest 2.1 fixes available on GitHub, while increasing the timeout limits to 4 hours (roughly four times the 2.0 baseline). This brought the mean reward to 92.1%. (p188)

> ...Mythos Preview represents only a modest accuracy improvement over our best Claude Opus 4.6 score (86.9% vs. 83.7%). However, the model achieves this score with a considerably smaller token footprint: the best Mythos Preview result uses 4.9× fewer tokens per task than Opus 4.6 (226k vs. 1.11M tokens per task). (p191)

To provide it access to refactoring as a tool also risks confusing it via too many tools.

It's the same reason that waffling for a few minutes via speech to text with tangents and corrections and chaos is just about as good as a carefully written prompt for coding agents.

And I'm not bragging. I'm expressing awe, and humility that I am finding a machine can match me on things that I find quite difficult. Maybe those things aren't so difficult after all.

By steering I mean more steering to flesh out the context of the problem and to find relevant code and perform domain-specific research. Not steering toward a specific solution.

The last few days I've been working on some particularly tricky problems, tricky in the domain and in backwards compatibility with our existing codebase. For both these problems GPT 5.2 has been able to come to the same ideas as my best, which took me quite a bit of brain racking to get to. Granted it's required a lot of steering and context management from me as well as judgement to discard other options. But it's really getting to the point that LLMs are a good sparring partner for (isolated technical) problems at the 99th percentile of difficulty

With claude code I'll ask it to read a couple of files and do x similar to existing thing y. It takes a few moments to read files and then just does it. All done in a minute or so.

I tried something similar with codex and it took 20 minutes reading around bits of file and this and that. I didn't bother letting it finish. Is this normal? Do I have something misconfigured? This was a couple of months ago.

I see this take somewhat often, and usually with similar lack of nuance. How do you come to this? In other cases where I've seen this it's from people who haven't worked in any context where performance or scientific computing ecosystem interoperability matters - missing a massive part of the picture. I've struggled to get through to them before. Genuine question.

This incident reflects extremely poorly on PostHog because it demonstrates a lack of thought to security beyond surface level. It tells us that any dev at PostHog has access at any time to publish packages, without review (because we know that the secret to do this is accessible from plain GHA secret which can be read from any GHA run which presumably run on any internal dev's PR). The most charitable interpretation of this is that it's consciously justified by them because it reduces friction, in which case I would say that demonstrates poor judgement, a bad balance.

A casual audit would have revealed this and suggested something like restricting the secret to a specific GHA environment and requiring reviews to push to that env. Or something like that.

https://docs.pypi.org/trusted-publishers/adding-a-publisher/

For a malicious version to be published would then require full merge which is a fairly high bar.

AWS allows similar

I've found structured output APIs to be a pain across various LLMs. Now I just ask for json output and pick it out between first/last curly brace. If validation fails just retry with details about why it was invalid. This works very reliably for complex schemas and works across all LLMs without having to think about limitations.

And then you can add complex pydantic validators (or whatever, I use pydantic) with super helpful error messages to be fed back into the model on retry. Powerful pattern

Was it 1% worse / unnoticeable? Did it become useless? The engineering is interesting but I'd like to see it tied to actual impact

We offer a feature to upload the invoice and we pull out all the rates for you. Uses LLMs under the hood. Fundamentally it's a "chatgpt wrapper" but there's a massive amount of work in tweaking the prompts based on evals, splitting things up into multiple calls, etc.

And it works great! Niche software, but for power users were saving them tens of minutes of monotonous work per day and in all likelihood entering things more accurate. This complements the manual entry process with full ability to review the results. Accuracy is around 98-99 percent.

Never had anything like this with claude code.

I've used Gemini 2.5 Pro quite a lot and like most people I find it's very intelligent. I've bent over backwards to use Gemini 2.5 Pro in another piece of work because it's so good. I can only assume it's the gemini CLI itself that's using the model poorly. Keen to try again in a month or two and see if this poor first impression is just a teething issue.

I told it that it did a pretty poor job and asked it why it thinks that is, told it that I know it's pretty smart. It gave me a wall of text and I asked for the short summary

> My tools operate on raw text, not the code's structure, making my edits brittle and prone to error if the text patterns aren't perfect. I lack a persistent, holistic view of the code like an IDE provides, so I can lose track of changes during multi-step tasks. This led me to make simple mistakes like forgetting a calculation and duplicating code.

Can run with `uvx --from lmnr-index --python 3.12 index run`

It's disingenuous to conclude that AI is no good at diagramming after using an impotent prompt AND refusing to iterate with it. A human would do no better with the same instructions, LLMs aren't magic.

This is the same as my previous comment https://news.ycombinator.com/item?id=42524125

[1] https://superwhisper.com/