From contributing half of its revenue to a standoff over a supply cutoff—and the resulting full break—Claude Code is forcing Cursor to urgently develop its own model.

According to Beating Monitoring, the subtle long-term symbiotic relationship between AI programming tool Cursor and the main model provider Anthropic was exposed by Business Insider. Internal employees described the relationship between the two companies as very strange, with Cursor heavily relying on Anthropic's API to drive its underlying coding functions, and nearly 40% to 50% of Anthropic's early revenue coming from calls made by Cursor users. However, while mutually beneficial, Anthropic is also secretly developing competing tools of the same kind.

Before releasing the terminal programming tool Claude Code, Anthropic executives privately reassured Cursor management, claiming that Claude Code was only an academic research experiment with no large-scale commercialization plans. However, after Claude Code was launched, it quickly became popular among developers, with annualized revenue soaring to $2.5 billion by February 2026, surpassing Cursor's current annualized revenue of $2 billion. Losing its technological exclusivity, Cursor soon experienced a wave of user defections, with many developers on social platforms announcing they had canceled their Cursor subscriptions to enable Claude Code.

Deeper panic arose from the threat of model supply disruptions. During negotiations with OpenAI over the acquisition of the AI programming tool Windsurf, Anthropic suddenly cut off model supplies to Windsurf. This supply cutoff served as a wake-up call for Cursor. On January 5, Michael Truell held an emergency all-hands meeting, deciding to fully develop its own models. Subsequently, Cursor developed the Composer series based on open-source models from the Moon of Darkness. By May this year, in Composer 2.5, the team’s independent R&D work accounted for over 85%, maintaining advantages of low cost and high concurrency while reducing dependence on interfaces from leading large companies.