OpenAI’s GPT-4.1 has some pretty standout results on SWE-bench Verified, Aider’s polyglot diff, and this leads to immediate adoption by top AI coding IDEs like Windsurf and Cursor.

SWE-bench: Real-World Coding, Real Progress

  • GPT-4.1 scores 54.6% on SWE-bench Verified, up from 33.2% for GPT-4o and 38% for GPT-4.5—a 21.4% absolute gain over 4.0 (OpenAI).
  • SWE-bench tests the model’s ability to solve real software engineering tasks in open-source Python repos, including bug fixes and feature additions.
  • This jump means GPT-4.1 is much better at exploring codebases, generating code that runs, and passing tests—crucial for devs building agents or automation.

Aider Polyglot: Multi-Language, Diff-Based Coding

  • Aider’s polyglot diff benchmark measures how well models handle code changes across multiple languages and output only the necessary diffs.
  • GPT-4.1 more than doubles GPT-4o’s score and beats GPT-4.5 by 8% absolute (OpenAI).
  • The model is specifically trained to follow diff formats more reliably, saving time and reducing merge conflicts for devs who rely on precise, minimal code changes.
  • For those who prefer full file rewrites, GPT-4.1’s output token limit is now 32,768—double that of GPT-4o.

Windsurf: Real-World IDE Impact

  • Windsurf now supports GPT-4.1, free for all users from April 14–21 (Windsurf Changelog, Reddit).
  • Performance gains:
    • 60% higher coding accuracy vs. GPT-4o
    • 30% more efficient tool calling
    • 50% fewer repeated/unnecessary edits
    • 40% fewer unnecessary file reads
    • 70% fewer incorrect file modifications
    • 50% less verbosity (details).
  • These improvements mean faster iteration, smoother workflows, and more accepted code changes on first review for engineering teams.

Cursor: GPT-4.1 Now Live

  • Cursor IDE has added GPT-4.1 as a selectable model—just enable it in Settings → Models (Cursor Forum, Reddit).
  • It’s currently free to try, letting users experience the new coding and tool-calling capabilities firsthand.
  • Cursor’s integration means developers can leverage GPT-4.1’s improved multi-language, diff, and instruction-following skills in a familiar, VS Code-like environment (Dr. Lee's Blog).

Real-World Impact: What These Improvements Mean

After using GPT-4.1 in both Windsurf and Cursor over the past week, the performance gains are immediately noticeable in daily development work. The model's improved understanding of codebases and more reliable diff generation means fewer frustrating back-and-forth iterations and more code that works on the first try.

For teams already using AI-powered development tools, the upgrade path is straightforward - and the productivity gains justify the transition effort.

Watch the video overview: