Claude credited as co-creator of programming language Elo • The Register

function Bernard Lambeau, a Belgium-based software program developer and founding father of a number of expertise firms, created a programming language referred to as Elo with the assistance of Anthropic’s Claude Code.

Beginning on December 25, 2025, he printed a sequence of posts in regards to the undertaking. The primary submit names Claude as a co-author.

“In roughly 24 hours of collaboration, we constructed a whole expression language with a parser, kind system, three compilers, a typical library, a CLI instrument, and a documentation web site. Not dangerous for a day’s work,” Lambeau and Claude wrote.

“Elo is not only a demonstration that AI can write code. It is a demonstration that people and AI can construct collectively – every contributing what they do greatest,” they added.

As an expression language that compiles to JavaScript, Ruby, and SQL, Elo is meant as a transportable option to deal with type validation, e-commerce order processing, and subscription logic.

Lambeau, founder and CTO of Klaro Cards and CEO of app consultancy Enspirit, just isn’t the primary to develop a programming language with the assistance of AI.

Steve Klabnik performed an analogous feat final 12 months with the Rue programming language. In September 2025, Geoffrey Huntley enlisted Claude to jot down a programming language referred to as Cursed. And earlier than that, Avital Tamir printed a Claude-authored repo for the Server programming language, with the caveat that the code just isn’t meant for precise use.

Claude Code isn’t the only AI-assisted programming method having a moment. AI biz Cursor created a rudimentary browser utilizing OpenAI’s GPT-5.2. And developer Ola Prøis used Cursor, powered by Claude, to create a Rust-based textual content editor referred to as Ferrite.

Claude customers usually acknowledge that their pair companion makes errors. However these dedicated to AI help discover it worthwhile to wash up after their helper.

“Claude Code is aware of virtually each tech stack (and might search the online), is aware of the Linux instructions that matter (search code, search & change, compile, take a look at, and so on.), and does that 10x sooner than I can do myself,” Lambeau advised The Register in an e mail interview.

Claude, he mentioned, permits him to make use of expertise he hasn’t mastered.

“I used to be already a full-stack developer (on languages, frameworks & reusable libraries I knew); I am now a full-stack++ dev as a result of I also can use languages, frameworks, and reusable libraries I barely know, if in any respect,” he defined.

“Claude Code falls quick if you do not have a terrific methodology. It wants suggestions loops to work high quality; in any other case, it derails. One potential suggestions loop is a human reviewing code and testing manually. However there’s a greater/complementary method if you would like it to work autonomously. On each Elo and Bmg.js, I’ve began by ensuring the testing methodology was efficient and scientifically sound. Claude writes the exams, executes them, discovers the place it is improper, and corrects itself. Spectacular.”

Lambeau mentioned he nonetheless must overview a few of Claude’s output.

“But when I learn the exams, agree with them, and might verify myself that they run high quality, I am 95 p.c positive it is already appropriate as a black field (not even studying the code),” he defined. “Then I can verify the structure and code high quality as a white field by having a common have a look at the code, however I haven’t got to know each element.”

Notably, Lambeau documented the sequence of prompts he used to create the language. The repo contains more than 100 tasks used to direct the AI mannequin. As well as, Lambeau has printed a video that describes his AI pair programming course of.

“I began in a setting the place Claude Code requested for permissions each 20 seconds and I used to be checking all the things it did,” Lambeau defined. “After a couple of successes, I rapidly arrange secure environments to have the ability to let Claude Code run in full autonomy (remoted pc & remoted Linux person, or operating in a Docker picture).”

Lambeau mentioned he nonetheless makes use of plan mode for advanced duties that require dialog with Claude.

“I overview the plan, be sure we have now a take a look at technique that is sound, then change Claude to autonomous mode and have a look at the exams, code & outcomes afterward,” he mentioned. “That is similar to a lead-dev/CTO + QA position, btw; it is simply a lot sooner than with human devs.”

Lambeau, who has a PhD in software program engineering and 30 years of expertise as a developer, mentioned each consultants and novices can profit from Claude Code, although he added {that a} service like Lovable may be extra approachable for these not already acclimated to the command line.

“Now, in relation to actual software program/product engineering, I believe Claude Code requires consultants (to this point),” he mentioned. “You continue to must information it rather a lot to maintain the standard excessive sufficient. You want very sturdy experience to do it successfully. At present (Claude will nonetheless enhance rather a lot), if you do not have the experience, you definitely find yourself with a giant mess of unmaintainable code.”

Many builders have mentioned as a lot about AI instruments. They’re extra helpful as an amplifier of experience than as a alternative for it. The scenario is analogous to the introduction of sequencing software program, digital synthesizers, and drum machines half a century in the past. These instruments enabled lots of people who weren’t nice musicians to make music. However they did not instill musical ability, and so they produced essentially the most fascinating work within the palms of practiced musicians.

The associated fee to do that, Lambeau mentioned, has been a Claude Max subscription that he bought in December for €180 a month. In that point, he says, he wrote Elo (https://elo-lang.org), accomplished Bmg.js (https://github.com/enspirit/bmg.js), accomplished Bmg’s documentation (https://www.relational-algebra.dev), and created the primary model of the Attempt web page (https://www.relational-algebra.dev/try).

“It is all private analysis and open-source tasks,” he mentioned. “It could have required a number of weeks to do the identical manually myself, and several other months to ask one other developer to do it. The associated fee can be principally due to the scientific & technical data switch in regards to the information language I envision. Surprisingly sufficient, it is very low-cost with Claude Code. There’s one thing true about the truth that these LLMs have a PhD.”

Lambeau defined that Elo is not only a option to take a look at Claude Code. He additionally sees it as an extension of his educational work in software program engineering and his private curiosity within the Relational Mannequin – he is served as a lecturer for database programs at Belgium’s UCLouvain.

“I am completely satisfied that we’d like higher/safer/easier programming languages inside no-code instruments and when interconnecting them (e.g. Zapier, Make, n8n, and so on.),” he mentioned. “Mainstream programming languages are very advanced, error-prone, typically harmful, and the packages are troublesome to overview for non-experts.”

“Extra importantly, they’re cumbersome to make use of for even easy information duties. I imply, even validating the schema and constraints of a knowledge file at runtime tends to be a nightmare in current languages. It is not built-in in any mainstream language; you instantly want validation libraries; most of them are restricted in what they’ll simply verify, so you might want to add devoted boilerplate code.”

In a world the place non-technical individuals can have the chance to jot down untrustworthy code with the assistance of AI, he mentioned, we’d like to have the ability to run that code safely.

“Elo goals at offering a secure & easy different,” he mentioned. “It will likely be a restricted language (non-Turing-complete, as we are saying) however tremendous secure & easy, and usable in 80 p.c of frequent information use circumstances. The very first no-code instrument to combine will probably be Klaro Playing cards, after all.” ®