Mechanize (@MechanizeWork) / X

Mechanize

161 posts

Mechanize

@MechanizeWork

We build environments and evals for training and evaluating frontier coding agents.

San Francisco, CA

Joined April 2025

Mechanize
@MechanizeWork
Jun 17
Dario claims that AI will write basically all code, and that within a year thereafter a large share of software engineering jobs will be lost. While his prediction about the automation of coding is right, the conclusion about jobs does not follow. Coding models are
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Mechanize
@MechanizeWork
Jun 17
Full podcast episode:
How bad data teaches models to write terrible code
From mechanizework.substack.com
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Mechanize
@MechanizeWork
Jun 17
Coding models will often do things that are reasonable during training but produce a terrible user experience. Models trained to conserve tokens will happily rerun 10-minute commands, wasting your time to avoid using a few more tokens.
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Mechanize
@MechanizeWork
Jun 17
Full podcast episode:
How bad data teaches models to write terrible code
From mechanizework.substack.com
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Mechanize
@MechanizeWork
Jun 17
Poor theory of mind is one of the main things keeping models from being good software engineers. They can resolve specific, reproducible bugs, but they struggle to anticipate what users want in the first place, which is much of what building good software requires.
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Mechanize
@MechanizeWork
Jun 17
Full podcast episode:
How bad data teaches models to write terrible code
From mechanizework.substack.com
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Mechanize
@MechanizeWork
Jun 16
Our new podcast on evals, with Max Niederman, Ege Erdil, and Stephen Yang. 0:00:00 – What's an eval, and how's it different from an RL environment? 0:19:33 – Why are models bad at building an emulator when the task is fully verifiable? 0:42:00 – How does training on bad data
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Mechanize
@MechanizeWork
Jun 16
Youtube: youtube.com/watch?v=UpO70A… Substack: mechanizework.substack.com/p/how-bad-data… Spotify: open.spotify.com/show/033krxvlE…
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Mechanize
@MechanizeWork
Jun 10
Replying to @MechanizeWork
Claude Fable 5 performs especially well on gameplay, scoring 91.5%. Opus 4.8 scored 77.4%. Interestingly, Fable 5 is a regression on audio. It scores 44.5% on audio, which is worse than Opus 4.8's 69.1% and GPT-5.5's 58.9%.
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Mechanize
@MechanizeWork
Jun 10
Claude Fable 5 is the first model we tested that gets perfect gameplay on Varoom 3D. Opus 4.8 got just 25% on the same game.
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Mechanize
@MechanizeWork
Jun 10
However, like earlier models, Fable 5 also fails to build an emulator that works on Spout, a homebrew cave-flying game. It diverges shortly after the loading screen, scoring 7.6%.
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Mechanize
@MechanizeWork
Jun 10
Claude Fable 5 scores 74.5% on GBA Eval, the best score to date. Given 24 hours, it writes an emulator that plays all but one game in our test set near-perfectly. It beats Opus 4.8's 24-hour score in under 2 hours.
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Mechanize
@MechanizeWork
Jun 9
We caught Grok Build 0.1 reward hacking on GBA Eval. After it got stuck while testing, it started hard-coding its emulator to perform better on the exact ROM it was testing against.
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Mechanize
@MechanizeWork
Jun 9
It didn't work. The ROMs that Grok has access to are example ROMs that we intentionally give the models so they can test locally. We actually grade their emulators on a set of hidden ROMs, so the hacking doesn't improve the score.
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Mechanize
@MechanizeWork
Jun 9
This is the first reward hacking attempt we've caught on GBA Eval. This case is somewhat subtle, not "malicious," and wouldn't have affected scores. This last point is exactly why we're careful to think about these behaviors when designing evals. Blog:
GBA Eval - Build a Game Boy Advance emulator in WebAssembly from scratch
From gbaeval.com
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Mechanize
@MechanizeWork
Jun 3
We are now seeking a puzzle maker to help us create puzzles that LLMs can't yet solve.
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Mechanize
@MechanizeWork
Jun 3
Apply here:
mechanize.work
Puzzle Maker
Design interesting and original puzzles that LLMs can't yet solve
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Mechanize
@MechanizeWork
Jun 1
Claude Opus 4.8 scores 70.9% on GBA Eval, the top score to date. Given 24 hours, it writes an emulator that plays most games, with working audio on all of them. It beats the previous best (GPT-5.5 at 53.2%) in under an hour.
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Mechanize
@MechanizeWork
May 14
We gave frontier AI coding agents 24 hours to write a complete Game Boy Advance emulator from scratch. GPT-5.5's emulator runs games best, with Claude Sonnet 4.6 and Opus 4.7 close behind. Gemini 3.1 Pro failed to produce a working emulator.
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Mechanize
@MechanizeWork
Jun 1
Here's Claude Opus 4.8's emulator running Collie Defense, where it scores 99.8% on video and 91% on audio. On most games we tested, gameplay is near-perfect, with some audio imperfections.
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Mechanize
@MechanizeWork
Jun 1
However, Opus 4.8's emulator is not perfect. On Varooom 3D, it diverges after around 2,000 frames. This is better than GPT-5.5 (whose emulator diverged after around 1,250 frames), but Opus 4.8 only scores 25% on this game.
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