What's the best programming language for coding agents?

summarybot

Cool line of questioning, but one piece of information is pivotal and critically not-yet-included: equivalent accomplishments in each language. For example, if I want to write standard things: web server, memoized fibonnaci, recipe search engine, what's the length-and-density of these outputs for each language? I think that would add in some ~normalization.

_doctor_love

I love Dan's writing. I really do. But I don't understand why he doesn't have some basic styling on his blog so that it's easier to read.

nylonstrung

One thing worth noting is that syntactic density doesn't necessarily mean cheaper because because symbols don't chunk/tokenize as well as plain English What I see from results like this is that the delta between languages is small enough now that it's hard to justify not not using something like Rust for the performance and correctness benefits if you're using LLMs and it fits the domain

aleph_minus_one

> Dynamically typed languages generally have a lower LLM token cost than traditional statically typed languages because omitting explicit type declarations makes the code more compact. If this was true, the programming languages that are very much on the left side of > https://danuker.go.ro/programming-languages.html#non-math-ma... > https://danuker.go.ro/programming-languages.html#overall-map should be very ideal for LLMs, in particular if they are dynamically typed. What I can tell you is: I experimented with AI prompts for generating Wolfram (Mathematica) code using some LLMs, and I can tell you that the results were very disappointing: in my experience LLMs have difficulties with programming languages that are - very concise, and - for which there is less code publicly available. Wolfram (Mathematica) is a good example of such a programming language.

dang

Related: Which programming languages are most token-efficient? - https://news.ycombinator.com/item?id=46582728 - Jan 2026 (91 comments)

clbrmbr

I discovered last week that Fable 5 can write perfect xTensa LX7 assembler code without tools or references. Mind blown. But, when working on a creative graphics task, the results were best in Lua, middling in integer-only C, and underwhelming in ASM in terms of creative depth.

cynicalpeace

I've long suspected that LLMs will just output pure bits eventually

DarkContinent

Is there a relationship between how good a programming language is for coding agents and how popular it is among humans? If so, wouldn't Python be the best language for agents, since it's is the most popular (and hence has the most context available for models)?

gr_norm

It's not clear to me how useful of a signal replicating existing pieces of well-known software is for this kind of evaluation, given what we know about how effectively LLMs can retrieve data from their training corpus and style-transfer it across different settings (programming languages here). That would explain their convergence in ability across different languages on the tasks in this post. I'd be far more interested in people's real-world experiences.

frollogaston

Any good LLM service (not just coding-focused ones) will write and run ad hoc code without being asked if your prompt involves lots of data. Gemini and Claude tend to pick Python with maybe some SQLite. Some of that must be due to portability alone, but it also means they'll make sure the model and tooling are good at those.

genxy

What is the best language for the user of the LLM? What is the best language to have high quality correctness oracles so that the user doesn't have to babysit the LLM and do lots of manual testing?

MichaelNolan

Ive been amazed at how well LLMs are at writing Gleam[1] and Lustre[2]. Compared to a mainstream language, there is basically zero gleam code in the training data. I have no evidence to back this up, but I suspect that languages that are good for humans[3] will be good for LLMs. Compiled, strongly typed, statically typed, immutable, pure functions, pattern matched, memory safe, etc. [1] https://gleam.run [2] https://lustre.hexdocs.pm [3] Yes I realize that languages features that are "good for humans" is a hotly debated topic. That's just my personal list for what I like in a language.

pianopatrick

I'd like to see the results for Ada on these same measures. On the theory that the Ada type system covers more classes of errors than other languages, and so AI can self correct better.

nogha

Cool seeing Guards of Atlantis 2 here. One thing that often happens with board games is rule issues in translations. Specifics that are clear in one language get lost in translation. Wolff Designa is out of Latvia. So not surprised there are some hard to interpret rules. It’s interesting that LLMs struggle with the board game rules like we do. I think game designers should get the llm to teach them from their rulebook. If an LLM can’t understand the rules good chance people will also be confused.

lowbloodsugar

First, How fast is the Zstd decoder in python at runtime? If rust and python are essentially the same cost, then chose rust. Second, I am surprised that python scored slightly better than rust. My own experience is that, when programming python, Claude would spend so much more time dealing with the code not working at runtime , while for any given rust problem, rust would likely fail at compile time, iterating faster and taking less tokens. Some tasks in python it just completely failed at, writing awful garbage. I suspect that is because there is much more awful garbage written in python. (I was trying to write an AI harness. Python seemed like the obvious choice. It was decidedly not). But in this article, python took slightly less time and tokens than rust for both experiments. I asked Claude: could you write a decoder, from memory, in python (dont do it, just tell me if you could) > Honestly: I could write something that's structurally right and would not decode a real .zst file. > The control flow I'm confident about from memory — frame/block parsing, the literals section dispatch, Huffman weight reconstruction, the backward bitstream reader, the interleaved three-state FSE loop, sequence execution with the repeat-offset rules and the overlapping-copy hazard. I'd expect to get that architecture right, and it would be readable. So perhaps asking it to do things that are in its memory is not a good benchmark. It was trained with the C "educational decoder, and every third-party port in Rust, Go, Java, JS." and offered a working link [1] to the former. [1] https://github.com/facebook/zstd/blob/dev/doc/educational_decoder/zstd_decompress.c

michaelteter

I'm not sure I trust a source that says "just 70 tokens average, nearly half of Clojure (109 tokens)". There's no reason to add the phrase "nearly half of", and there's especially no reason to add it when it's significantly far away from half. But on the main topic, I still feel that Go is an excellent choice for LLMs. There is pretty much just one way of doing most things, and the available training data is pretty consistent. This is very different from Python, where training data is polluted (I presume) with tons of code written by non-software engineers and demonstrating many different ways of doing the same thing. Also a big plus for Go is the tooling. Fast compiles and good linting shortens the iteration cycle time, resulting in less need for me to tell the LLM to correct mistakes. For some reason, most LLMs I've used default to wanting to write Python. I have to repeatedly teach them to use Go unless there is a very compelling reason to choose otherwise. I would personally rather see and use Clojure, but I don't feel its ecosystem would provide the same benefits as Go, including obviously the easy single binary distribution.

chvid

So Javascript beats typescript in correctness???

est

Python has a less known advantage because it had no curly braces, so LLMs can focus its attention to logic instead of syntax. https://blog.est.im/2026/stdin-11

kayashaolu2

This is a great discussion: I wonder though if we are asking the right question. Yes, absolutely language choice can play a large role in the efficiency of coding agents. The point about Rust is right: static typing provides a fast verification loop at compile time. I would argue though that the way the codebase is composed could actually generalize the concept of "easy verifiability" past the actual coding language. For instance, if an application can be broken down into components that have a verifiable contract in how they are to be used, then an LLM can load only the relevant modules into its context and fully understand how to use them and fix them if needed. It is also easier for the LLM to verify the functionality of a component rather than the entire system. Additionally, in an application composed of functioning components, issues are more likely to occur at the boundaries between them, which the LLM can focus on rather than having to always consider the entire application that it most likely can't load fully into its context. A well designed componentized Python application will likely be far more efficient for modification by an LLM than a large Rust monolith.