Not trying to be cynical here, but I am genuinely interested is there a reason why these LLM don't/can't/won't apply some deterministic algorithm? I mean, counting characters and such, we have solved those problems ages ago.

Thanks, Simon! I saw the same approach (numbering the individual characters) in GPT 4.1's answer, but not anymore in GPT 5's. It would be an interesting convergence if the models from Anthropic and OpenAI learned to do this at a similar time, especially given they're (reportedly) very different architecturally.

Does that mean they've managed to post train the thinking steps required to get these types of questions correct?

Or they’d rather use that context window space for more useful instructions for a variety of other topics.

Did you try "literal but with an o"?

I know this word, it's French and it means coastline, coastal, something at the edge of the land and sea ! We use it in French a lot to describe positively a long coastline. I'm surprised it's used in an English context, but all French words can be used in English I guess if you're a bit "confiant" about it !

Yep, there is still a room for improvement, but my point is that the LLMs are getting better at something they're "not supposed to be able to do".

Quartiles sound like an especially brutal game for an LLM, though! Thanks for sharing

Even GPT 3.5 is okay (but far from great) at Base64, especially shorter sequences of English or JSON data. Newer models might be post-trained on Base64-specific data, but I don't believe it was the case for 3.5. My guess is that as you say, given the abundance of examples on the internet, it became one of the emergent capabilities, in spite of its design.

Why test for something? I find it fascinating if something starts being good at task it is "explicitly not designed for" (which I don't necessarily agree with - it's more of a side effect of their architecture).

I also don't agree that nobody is using this for - there are real life use cases today, such as people trying to find meaning of misspelled words.

On a side note, I remember testing Claude 3.7 with the classic "R's in the word strawberry" question through their chat interface, and given that it's really good at tool calls, it actually created a website to a) count it with JavaScript, b) visualize it on a page. Other models I tested for the blog post were also giving me python code for solving the issue. This is definitely already a thing and it works well for some isolated problems.

One reason for testing this is that it might indicate how accurately models can explain natural language grammar, especially for agglutinative and fusional languages, which form words by stringing morphemes together. When I tested ChatGPT a couple of years ago, it sometimes made mistakes identifying the components of specific Russian and Japanese words. I haven’t run similar tests lately, but it would be nice to know how much language learners can depend on LLM explanations about the word-level grammars of the languages they are studying.

Later: I asked three LLMs to draft such a test. Gemini’s [1] looks like a good start. When I have time, I’ll try to make it harder, double-check the answers myself, and then run it on some older and newer models.

[1] https://g.co/gemini/share/5eefc9aed193

https://www.anthropic.com/news/analysis-tool

Seems like they already built this capability.

Character level LLMs are used for detecting insults and toxic chat in video games and the like.

I remember people making the exact same argument about asking LLMs math questions back when they couldn't figure out the answer to 18 times 7. "They are text token predictors, they don't understand numbers, can we put this nonsense to rest."

The whole point of LLMs is that they do more than we suspected they could. And there is value in making them capable of handling a wider selection of tasks. When an LLM started to count the numbers of "r"s in "strawberry", OpenAI was taking a victory lap.

I made a response to this counterpoint in a blog post I wrote about a similar question posed to LLMs (how many b's are in blueberry): https://news.ycombinator.com/item?id=44878290

> Yes, asking an LLM how many b’s are in blueberry is an adversarial question in the sense that the questioner is expecting the LLM to fail. But it’s not an unfair question, and it’s objectively silly to claim that LLMs such as GPT-5 can operate at a PhD level, but can’t correctly count the number of letters in a word.

It's a subject that the Hacker News bubble and the real world treat differently.

Wouldn't a llm that just tokenized by character be good at it?