one year on
Cursor ships Composer, its first in-house coding model, in Cursor 2.0
Cursor stakes its claim to the coding-model layer, betting a 4x speed edge and an agent-first interface beat raw frontier intelligence — on the same day Cognition ships SWE-1.5 for Windsurf.
Originally published Published on this site
Cursor released version 2.0 of its IDE on Wednesday, and with it Composer, the company’s first in-house coding model. Anysphere describes Composer as a frontier model roughly four times faster than similarly intelligent models, completing most turns in under 30 seconds, and trained with tools including codebase-wide semantic search. It was built with reinforcement learning and a mixture-of-experts architecture, and trained on interactive development challenges rather than static datasets.
Alongside the model, the interface is agent-first. Cursor 2.0 lets users run many agents in parallel without interference, using git worktrees or remote machines, and supports having several models attack one problem so the developer picks the best result. The company also begins addressing the bottlenecks it says emerge once agents write more code: reviewing it and testing it, the latter via a native browser tool the agent uses to check its own work.
The numbers come with a caveat: Cursor’s benchmark chart is internal. On it, Composer underperforms the “best frontier” on intelligence, outperforms top-tier open models, and far outpaces everything on speed. In Ars Technica’s reporting, a non-representative sample of developers said Composer is not ineffective but too expensive, given a perceived capability gap with the big models.
The same day, Cognition released SWE-1.5 for Windsurf, a frontier-size model it says runs at up to 950 tokens per second on Cerebras hardware — 6x faster than Haiku 4.5 and 13x faster than Sonnet 4.5. Both releases put speed at the center of the pitch.
The record
writes that on Cursor's internal benchmark Composer trails the best frontier models on intelligence but vastly outpaces competitors on speed, and that developers he spoke with found Composer not ineffective but too expensive given a perceived capability gap — an invitation, in effect, to let developers' own results settle it
says SWE-1.5 is a frontier-size model with hundreds of billions of parameters achieving near-SOTA coding performance, served with Cerebras at up to 950 tokens per second — 6x faster than Haiku 4.5 and 13x faster than Sonnet 4.5 — and argues developers shouldn't have to choose between an AI that thinks fast and one that thinks well
One year later — open only if you can handle spoilers
Composer started Cursor's push to own its models, with mixed optics: its March 2026 successor, Composer 2, turned out to be built on Moonshot AI's open-weights Kimi 2.5, which Cursor acknowledged only after users spotted it. The business kept climbing — a $2.3 billion raise at a $29.3 billion valuation that autumn, then a $60 billion all-stock acquisition agreement with SpaceX in June 2026.
Filed
Compiled and edited by Adam Allcock.
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