Cursor's inaugural Developer Habits Report is the most data-rich picture of AI-assisted software development published to date. Built from aggregated usage across Cursor's entire platform, it covers agent sessions, token consumption, accepted diffs, and merged PR activity, spanning all major model families. The findings are striking, and in some cases, unsettling.

The numbers that matter

The headline stat is simple: coding speed has doubled year-over-year, PRs are getting larger and deeper, and agent-generated code is surviving review at higher rates than ever. But the details behind that headline tell a more nuanced story.

• Lines added per developer per week went from 3.6K in January 2025 to 8.6K by May 2026, a roughly 2.4x increase.
• Lines added per PR are up roughly 2.5x year over year, and the growth rate is accelerating.
• Mega PRs, defined as PRs with at least 1,000 lines changed, are becoming more common. There was a notable jump in January 2026, when many developers were trying out the latest improvements in coding agents and models.
• In just the last two months, average tool calls per session have risen roughly 30%. Coding agents are taking on more complex work, reading and editing files, searching code, running shell commands, and browsing the web more frequently.
• The share of accepted AI lines still present after 60 minutes has risen from roughly 76% to 81%, suggesting the code quality is improving, not just the volume.

The model economics are wild

One of the most practically useful sections of the report is its breakdown of cost across model families. Cost per agent request varies by nearly 9x across model families, showing that the same workflow can have very different cost profiles depending on the model behind it. But raw request cost is a misleading metric.

Cost per accepted line varies by roughly 7x across model families, compared with nearly 9x for cost per request, suggesting that higher-cost models partially make up the difference by producing more accepted code per request. In other words, expensive models earn some of their premium back through efficiency.