Ludwig Pettersson

I build internet stuff. Previously creative director of @stripe, original designer of @openai, and founder of @quillchat.

[Ludwig Pettersson @ludwig]

this one was better

[Ludwig Pettersson @ludwig]

NYC Compute

[Ludwig Pettersson @ludwig]

Signal: Nominal

[Ludwig Pettersson @ludwig]

@nickarner will share soon!

[Ludwig Pettersson @ludwig]

I was able to remove 90% of my deterministic guard rails, all my pre-loop classifiers, and reduce my system prompt by ~30% moving from GPT 5.4 -> 5.5. (tbf it had built up a lot of cruft 5.4 probably didn't need)

5.5 did it itself over ~8 hours total (never had anything run this long before! 3-4 sessions, mostly unattended), then it took me 2-3 hours to review and clean up. Would've taken me ~2 weeks on my own, probably.

[Ludwig Pettersson @ludwig]

@bionicashish it's a classic https://t.co/RT5ydFZMpP

[Ludwig Pettersson @ludwig]

weeeee

[Ludwig Pettersson @ludwig]

@bdc lets gooooo

[Ludwig Pettersson @ludwig]

bonus of working on an image/video agent: I thoroughly enjoy skimming through the eval results

[Ludwig Pettersson @ludwig]

Also the irony that LLMs aren't that great at writing system prompts

(tbc probably a skill issue)

[Ludwig Pettersson @ludwig]

Every time I catch myself trying to do clever system prompts + deterministic guardrails (old world thinking) and instead rethink it into a few simple primitives, my little agent loops get like 2-3x more capable and 90% less brittle

Also: evals. Evals evals evals.

[Ludwig Pettersson @ludwig]

@DamiDina something new I'm experimenting with

[Ludwig Pettersson @ludwig]

spaghetti

[Ludwig Pettersson @ludwig]

@fredzaw something new!