Bartosz Jedrzejewski (@e4developer) / X

Bartosz Jedrzejewski

2,743 posts

Bartosz Jedrzejewski

@e4developer

Engineering manager @meta MSL. After work - @BattleCastGG and e4developer.com

London, England

Joined January 2011

Bartosz Jedrzejewski
@e4developer
Jul 9
I turned Dungeons & Dragons combat into an LLM benchmark. Not serious research, very much a learning experiment: eval harness bugs, tactical decisions, dice rolls, and a real OpenRouter bill. I wrote up D20bench here:
D20bench - Benchmarking LLMs with Dungeons & Dragons Combat
From e4developer.com
Bartosz Jedrzejewski
@e4developer
Jul 9
Incredibly proud for the team, especially for the contributions to our CUA and Coding capabilities! Performance on browser tasks is truly impressive - give it a try! There is so much more to come!
Alexandr Wang
@alexandr_wang
Jul 9
1/ muse spark 1.1 is an industry-competitive agentic and coding model. across many agentic evals it rivals gpt-5.5 and opus-4.8. available now through the new meta model api and in meta ai. 🧵
Bartosz Jedrzejewski
@e4developer
Apr 27
I think we did a pretty good job at MSL 😎
Arena.ai
@arena
Apr 27
GPT-5.5 by @OpenAI is now live in the Arena, landing across multiple leaderboards. Here’s how it ranks by modality: - Code Arena (agentic web dev): #9, a strong +50pt jump over GPT-5.4 - Document Arena (analysis & long-content reasoning): #6, on par with Sonnet 4.6 - Text
Bartosz Jedrzejewski
@e4developer
Apr 27
I’ve never had as much fun being software engineer as I’m having now. The speed of turning ideas into concrete work is something else!
Bartosz Jedrzejewski
@e4developer
Apr 24
@ColbyPoulson really awesome youtube channel! I thought you may be interested in battlecast.gg - free D&D battle simulator I wrote (it turns out that about 10 cats are a fair fight for lvl1 wizard). Let me know if you like it!
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