"Btw, we rolled this out over 3 weeks ago and I think you're the first person to ask about it on HN. There was one earlier question by email. I think that qualifies as a splash-free dive."

I had no idea and I'm an HN addict!

https://github.com/pauek/arc-sbcl

And there's no version of Anarki that runs on sbcl?:

https://arclanguage.github.io/

>SBCL derives most of its code from CMU CL, created at Carnegie Mellon University. Radical changes have been made to some parts of the system (particularly bootstrapping) but many fundamentals (like the mapping of Lisp abstractions onto the underlying hardware, the basic architecture of the compiler, and much of the runtime support code) are only slightly changed. Enough changes have been made to the interface and architecture that calling the new system CMU Common Lisp would cause confusion - the world does not need multiple incompatible systems named CMU CL. But it's appropriate to acknowledge the descent from the CMU hackers (and post-CMU CMU CL hackers) who did most of the heavy lifting to make the system work. So the system is named Steel Bank after the industries where Andrew Carnegie and Andrew Mellon, respectively, made the big bucks.

  SBCL - Sanely Bootstrappable Common Lisp

SBCL redid the logic heavily into being able to host the core SBCL compiler parts in any mostly-complete (does not have to be complete!) ANSI CL implementation, then uses that to compile the complete form.

Meaning you can grab SBCL source tarball, plus one of GNU clisp, ECL, Clozure CL, even GNU Common Lisp at one point, or any of the commercial implementations, including of course CMUCL, and C compiler (for the thin runtime support) and build a complete and unproblematic SBCL release with few commands

well yea, lispworks and allegro are expensive commercial projects. I wish sbcl, the defacto best open source option had better tooling. emacs is great and all for the true believers but I'm an unwashed vscode user. For plenty of reasons I can't justify it in my startup but I'd love to spend more time working with common lisp for personal projects but my time is limited so I prefer clojure or rust.

But putting emacs aside, the SBCL tooling seems reasonable to me. The real reason I rarely reach for lisp these days is not the tooling, but because the Common Lisp library ecosystem is a wasteland of partial implementations and abandoned code bases.

It's also been my experience that LLMs are better at writing more mainstream languages, especially "newbie-proof" languages like Go.

In any case, I don't see why one would reach for Allegro or Lispworks over SBCL unless one really enjoys writing lisp by hand and needs specific features they offer that SBCL doesn't. I would imagine those features are vanishingly few.