Charlie Snell
@sea_snell
PhD student @berkeley_ai; research @cursor_ai; prev @GoogleDeepMind. My friend told me to tweet more. I stare at my computer a lot and make things
6.5K Following 8.3K Followers
Think of an AI PhD as an artistic pursuit
We’re introducing Cursor 3. It is simpler, more powerful, and built for a world where all code is written by agents, while keeping the depth of a development environment.
Earlier this week, we published our technical report on Composer 2.
We're sharing additional research on how we train new checkpoints. With real-time RL, we can ship improved versions of the model every five hours.
Show more
Cursor can now search millions of files and find results in milliseconds.
This dramatically speeds up how fast agents complete tasks.
We're sharing how we built Instant Grep, including the algorithms and tradeoffs behind the design.
Show more
Composer 2 tech report !
We're releasing a technical report describing how Composer 2 was trained.
We're releasing a technical report describing how Composer 2 was trained.
Congrats to the @cursor_ai team on the launch of Composer 2!
We are proud to see Kimi-k2.5 provide the foundation. Seeing our model integrated effectively through Cursor's continued pretraining & high-compute RL training is the open model ecosystem we love to support.
Note: Cursor accesses Kimi-k2.5 via @FireworksAI_HQ ' hosted RL and inference platform as part of an authorized commercial partnership.
Show more
It's a really good model! Excited for more people to try it
Composer 2 marks the one-year anniversary of our large model training efforts. Since then, we've built an exceptionally talent-dense team of ~40 people with some of the best researchers and engineers from the labs, academia, industry, and more heterogeneous backgrounds.
And we are exclusively focused on coding. We don't care about models that can respond to emails, do your tax returns, or be your friend.
Every FLOP, token, parameter, and researcher is entirely dedicated to software engineering.
Show more
now that i can talk about it, i had early access to composer 2 and have been using it for the past few days. quick thoughts:
- feels very close to gpt-5.4-high at lesser price
- follows instructions really well
- holds structure over long threads without much context rot
- very noticeable leap from composer-1.5 but also codex 5.3 and opus 4.6 low/medium in reasoning + code quality
- "fast" genuinely fast (2-3x faster than the non-fast variant), beats opus-4.6-high on code throughput
cursor cooked. absolutely banger launch that's gonna save people serious money
Show more
Composer 2 is now available in Cursor.
We trained Composer to self-summarize through RL instead of a prompt.
This reduces the error from compaction by 50% and allows Composer to succeed on challenging coding tasks requiring hundreds of actions.
Show more
We're sharing a new method for scoring models on agentic coding tasks.
Here's how models in Cursor compare on intelligence and efficiency:
See you Sunday!
Participants will get free Cursor credits and the winners will get a year of Cursor Ultra.
Cursor team will be on hand.
We believe Cursor discovered a novel solution to Problem Six of the First Proof challenge, a set of math research problems that approximate the work of Stanford, MIT, Berkeley academics. Cursor's solution yields stronger results than the official, human-written solution.
Notably, we used the same harness that built a browser from scratch a few weeks ago. It ran fully autonomously, without nudging or hints, for four days.
This suggests that our technique for scaling agent coordination might generalize beyond coding.
Show more
Cursor now shows you demos, not diffs.
Agents can use the software they build and send you videos of their work.
People who do model merging are like the flat earthers of deep learning
Composer 1.5 is now available.
We’ve found it to strike a strong balance between intelligence and speed.
Think of an AI PhD as an artistic pursuit
