Gemini 3 Pro vs Claude Sonnet 4.5: Hands-On Antigravity IDE Review
Google launched Antigravity and Gemini 3 two days ago. I’ve spent the last 48 hours testing both—and comparing Gemini 3 Pro vs Claude Sonnet 4.5 in real-world coding tasks.
If you’ve been following the AI coding tool space, you’ve probably noticed Antigravity looks a lot like Windsurf. That’s because Google acquired the Windsurf team in July for $2.4 billion and licensed the technology. Internally at Google, this acquisition happened through DeepMind, where the Windsurf founders landed. I got my first look at Antigravity not long before the public did.
Gemini 3 Pro vs Claude Sonnet 4.5: Real-World Performance
I tested Gemini 3 Pro through Gemini CLI on several coding tasks. In my unscientific but practical tests, Gemini 3 Pro shows more complete responses than Claude Sonnet 4.5, especially when paired with Gemini CLI.
The model feels different. More thorough. Less likely to give you a partial solution and wait for you to ask for the rest. This aligns with what I saw in the internal Gemini 3 snapshots I tested before the public release on other Google platforms.
TechRadar ran a comparison where Gemini 3 Pro built a working Progressive Web App with keyboard controls without being asked. Claude struggled with the same prompt. The benchmark data backs this up. Gemini 3 Pro scored 2,439 on LiveCodeBench Pro compared to Claude Sonnet 4.5’s 1,418.
Claude still edges out Gemini on SWE-Bench Verified testing (77.2% vs 76.2%), but Gemini wins on most other coding benchmarks.
My take: Gemini 3 is a massive improvement over Gemini 2.5, and puts itself squarely into the discussion with Sonnet 4.5 for effective coding models. We have a legitimate competition on that front.
Quick Comparison: Gemini 3 Pro vs Claude Sonnet 4.5 vs Antigravity
| Feature | Gemini 3 Pro | Claude Sonnet 4.5 | Antigravity IDE |
|---|---|---|---|
| LiveCodeBench Score | 2,439 | 1,418 | Uses Gemini 3 or Claude |
| SWE-Bench Verified | 76.2% | 77.2% | Depends on model |
| Response Style | More complete, thorough | More concise | Varies by model |
| Best Interface | Gemini CLI | Claude Code | Antigravity IDE |
| Pricing | Free (rate limits) | Paid ($20/month) | 100% free |
| Browser Automation | No | No | Yes ✓ |
| Subagents | Limited | Yes (Claude Code) | No |
| Extension Support | N/A | Full VS Code | Open VSX only |
Google Antigravity First Impressions
Antigravity is Google’s take on the agentic IDE. Think Cursor, Windsurf, or Codeium Windsurf.
I don’t love it. But not because Antigravity is good or bad.
I prefer the CLI experience to the agentic IDE approach. Antigravity was similar to my experience with Cursor (pre-Cursor 2.0), but with more polish. The interface is clean, the multi-pane setup works well, and the agent orchestration is better than I expected.
But it’s still an IDE-centric agent experience, and that’s just not my workflow preference. I work in the terminal. I use Gemini CLI for work and a mix of Gemini CLI and Claude Code for personal projects. The IDE approach feels like it’s solving a different problem than the one I have.
Two things stood out as limitations:
-
No subagents - Unlike Claude Code’s specialized agents for different tasks, Antigravity doesn’t have that modularity. You get one agent doing everything.
-
IDE lock-in - The experience assumes you want to work primarily in the IDE. That might work for some developers, but it’s not how I code.
Antigravity vs Windsurf: Key Differences
Antigravity looks a lot like Windsurf. Developers on X and Hacker News noticed the similarities. One developer put it bluntly: “The interface looks nearly identical to VS Code… and Windsurf… and Cursor.” It has a massively talented engineering team behind it, and growing adoption inside Google. I have no doubt it will distinguish itself in short order. It’s just not my preference.
The main differences:
- Antigravity is 100% free with generous rate limits
- Powered by Gemini 3 Pro (but also supports Claude)
- Browser automation and multi-agent orchestration that Cursor and Windsurf don’t have. This is a legitimately awesome tool that I will leverage when testing and debugging UI issues.
- Uses Open VSX registry instead of the VS Code marketplace (which causes extension friction)
If you’re a frontend developer or someone who wants background agents handling tasks, Antigravity is worth trying.
For me, it’s not a replacement for my current workflow.
Gemini CLI Developer Experience
I’ve been using Gemini CLI since before it launched. It’s my day job to make it better.
The CLI got a major upgrade recently. Google overhauled the rendering foundation to fix flickering screens, bouncing prompts, and unstable output. It’s significantly better than it was six months ago.
Gemini 3 integration into the CLI unlocked better agentic coding. The model handles complex, multi-file refactors well. Context handling improved noticeably from Gemini 2.5 Pro.
Gemini CLI still needs work. I’m not going to pretend otherwise. But it’s improving fast, and with Gemini 3, it’s become a legitimate everyday coding assistant.
Capacity Issues and Limitations
This is the frustrating part.
Early adopters report hitting capacity limits quickly. I’ve seen “model provider overload” errors multiple times. Credits run out faster than expected.
Google is addressing this, but right now it’s a real issue. If you’re trying Antigravity or Gemini 3, expect to hit rate limits.
It’s annoying, but it’s a solvable problem. Google scaled Gemini 2.5 Pro capacity over time. They’ll do the same with Gemini 3.
FAQ
Is Gemini 3 Pro better than Claude Sonnet 4.5 for coding?
For most coding tasks, Gemini 3 Pro scores higher on benchmarks (2,439 vs 1,418 on LiveCodeBench Pro). However, Claude edges out on SWE-Bench Verified testing (77.2% vs 76.2%). “Better” depends on your workflow and the specific tasks you’re doing. I find Gemini 3 gives more complete responses, while Claude is more concise.
Should I switch from Cursor to Antigravity IDE?
If you’re already using Cursor or Windsurf, Antigravity is worth trying—it’s 100% free with generous rate limits. The interface is similar, but Antigravity adds browser automation and multi-agent orchestration. The main downside is the Open VSX registry instead of the VS Code marketplace, which limits extension availability.
What’s better: Antigravity IDE or Gemini CLI?
It depends on your workflow preference. Antigravity is better if you want an IDE-centric experience with visual feedback and multi-pane editing. Gemini CLI is better if you prefer terminal-based workflows and want modular agent capabilities. I personally prefer Gemini CLI, but both use the same underlying Gemini 3 model.
Are the capacity issues with Gemini 3 a dealbreaker?
Not for me. Early adopters are hitting rate limits, but Google has a track record of scaling capacity over time (they did it with Gemini 2.5 Pro). If you’re evaluating Antigravity or Gemini 3 now, expect occasional “model provider overload” errors, but they should improve in the coming weeks.
Should You Try Antigravity IDE?
My recommendations:
- Using Cursor or Windsurf? Try Antigravity—it’s free and adds browser automation features they don’t have.
- Prefer CLI workflows? Stick with Gemini CLI. The Gemini 3 integration is a major upgrade.
- Need reliability now? Claude Code with Sonnet 4.5 still offers the most stable experience without capacity issues.
Gemini 3 is competitive with Claude Sonnet 4.5 for the first time. Antigravity is well-built and free. Both have growing pains that Google is addressing.
I’m using Gemini CLI for daily work and keeping Claude Code for when I need specialized agents. Try both and see what fits your workflow.
Disclaimer: I work on Gemini CLI at Google. These are my personal opinions, not Google’s official position. I tested these tools like any other developer would.