Eighteen months ago, Devin was a parlor trick. An impressive demo that fell apart on real codebases.
Today? It’s merging 67% of its pull requests and solving problems four times faster than its original version. The catalyst: Anthropic’s Claude Sonnet 4.5, which Cognition Labs integrated in late September 2025.
The numbers tell a story that’s hard to ignore.
The Performance Leap in Context
Let’s start with what changed:
| Metric | 2024 (Original Devin) | December 2025 |
|---|---|---|
| PR Merge Rate | 34% | 67% |
| Problem-Solving Speed | Baseline | 4x faster |
| Resource Efficiency | Baseline | 2x better |
| Task Time Reduction | – | Up to 80% |
That PR merge rate deserves attention. Going from 34% to 67% means developers are accepting Devin’s work two-thirds of the time. Not tweaking it. Not rewriting it. Merging it.
At Gumroad, Devin merged over 1,500 PRs with an 85%+ acceptance rate, becoming a top contributor to their repositories. That’s not a proof-of-concept. That’s a teammate.
What Claude Sonnet 4.5 Brought to the Table
When Cognition rebuilt Devin on Claude Sonnet 4.5 in September 2025, the improvements were immediate:
- 2x faster execution compared to the previous model
- 18% increase in planning performance
- 12% improvement on Junior Developer Evals
But the real story is what Sonnet 4.5 enables architecturally. The model maintains focus on complex, multi-step tasks for over 30 hours – something earlier models couldn’t do without context degradation.
Devin doesn’t just write code faster. It thinks through problems more effectively, tests its own code more rigorously, and produces production-ready output more consistently.
Anthropic’s 77.2% SWE-Bench Verified score for Sonnet 4.5 isn’t just a benchmark. It’s the foundation Devin now builds on.
Real-World Use Cases: Where Devin Actually Works
Enterprise customers are deploying Devin for tasks that used to require senior engineers:
Security Vulnerability Resolution
When Log4j-style vulnerabilities drop, you need fast, comprehensive remediation across hundreds of repositories. Devin can scan, patch, and submit PRs at a pace no human team can match.
Repository Migration and Modernization
Moving from Python 3.8 to 3.12? Migrating to a new framework? Devin handles the grunt work – updating syntax, fixing deprecations, running tests – while humans review the edge cases.
Unit Test Generation
Devin now writes meaningful test coverage, not just placeholder assertions. For teams with test debt, this is time reclaimed.
The December 2025 Update: What’s New
Cognition pushed a significant update to all enterprise customers in December 2025:
- ~10% speed increase for tasks requiring extensive edits
- Cost efficiency improvements for high-volume usage
- New API v3 endpoints for tracking consumption metrics
- Jira project mapping for better workflow integration
- Visual indentation for child sessions – sounds minor, but makes complex task chains readable
This is the kind of incremental polish that separates tools from infrastructure.
How Devin Compares Now
The AI coding landscape has consolidated fast. Here’s where Devin fits:
| Tool | Primary Strength | Weakness |
|---|---|---|
| Devin | Autonomous task completion | Requires supervision for critical code |
| Cursor | IDE-integrated multi-agent | Acquisition-heavy, integration uncertain |
| Windsurf | GPT-5.2 Codex integration | Acquired by Cognition |
| GitHub Copilot | Ecosystem integration | Less agentic than competitors |
Devin’s acquisition of Windsurf means Cognition now controls both the autonomous agent (Devin) and a full IDE experience. That’s a powerful combination – if they can integrate cleanly.
The Productivity Paradox
Here’s what nobody’s talking about: if Devin can merge 67% of PRs and run 80% faster, what happens to mid-level engineering headcount?
I’ve been watching engineering team structures for years. The pattern is clear: AI amplifies senior engineers while displacing task-focused roles. One senior engineer with Devin can output what previously required a team of three or four.
This isn’t doom-and-gloom. It’s economics. The same thing happened when IDEs replaced text editors, when version control replaced email patches. The engineers who learn to orchestrate AI agents will thrive. The ones who compete with them won’t.
What’s Next for Devin
Cognition hasn’t announced specifics, but the trajectory suggests:
1. Tighter Windsurf integration – expect a unified product by mid-2026
2. Specialized domain agents – security, mobile, infrastructure
3. Enterprise pricing pressure – as efficiency improves, per-seat models may shift to consumption-based
The Agentic AI Foundation’s MCP protocol will also matter here. Devin’s ability to interact with external tools depends on standards adoption.
The Bottom Line
Devin’s jump from 34% to 67% PR merge rate represents a categorical shift. This isn’t AI assisting developers. This is AI operating as a developer – with humans as reviewers and architects.
The implications are enormous. And if you’re not experimenting with autonomous agents now, you’re already a cycle behind
FAQ
Is Devin worth the enterprise pricing?
Depends on your volume. For teams processing 50+ tickets weekly, the math works. For smaller teams, Cursor’s pricing may be more appropriate.
How do I test Devin before committing?
Cognition offers pilot programs for enterprise customers. For individual developers, the waitlist is still active.
What happened to Windsurf after the acquisition?
Windsurf continues operating, with Cognition integrating its IDE features into the broader Devin ecosystem over 2026.
