Claude Opus 4.5 vs GPT-5.2 vs Gemini 3: AI Coding Compared
The AI coding landscape transformed in late 2025: On the SWE-bench Verified leaderboard, Gemini 3 Pro leads at 77.4%, Claude Opus 4.5 (released November 24, 2025) follows at 76.8%, and GPT-5.2 Codex scores 71.8% but boasts a perfect AIME score. This head-to-head comparison covers real benchmarks, pricing, and which model fits your workflow.
Gemini SWE-bench
Claude SWE-bench
GPT-5.2 SWE-bench
GPT-5.2 context tokens
Key Takeaways
January 2026 marks an unprecedented moment in AI coding assistants. All three leading models now score above 70% on SWE-bench Verified - a benchmark that seemed impossible just 18 months ago. Claude Opus 4.5, GPT-5.2 Codex, and Gemini 3 Pro each bring unique strengths to the table. This comprehensive comparison will help you choose the right model for your development needs.
Model Overview & Key Differences
Each model represents a distinct philosophy in AI development:
Released: November 24, 2025
Company: Anthropic
Specialty: Extended thinking, code quality
SWE-bench: 76.8%
Pricing: $5/$25 per 1M tokens
Best for: Production code, complex debugging
Released: December 2025
Company: OpenAI
Specialty: Code execution, large context
SWE-bench: 71.8%
Pricing: $1.75/$14.00 per 1M tokens
Best for: Rapid prototyping, agents
Released: December 2025
Company: Google
Specialty: 1M context, multimodal
SWE-bench: 77.4%
Flash: $0.50/$3.00 per 1M tokens
Best for: Large codebases, budget teams
Benchmark Performance Comparison
Real performance data from official sources and independent verification:
| Benchmark | Claude Opus 4.5 | GPT-5.2 Codex | Gemini 3 Pro |
|---|---|---|---|
| SWE-bench Verified* | 76.8% | 71.8% | 77.4% |
| ARC-AGI-2 | ~48% | 54.2% | ~45% |
| AIME 2025 | ~85% | 100% | ~80% |
| HumanEval | 96.4% | 95.8% | 94.2% |
| MBPP+ | 91.2% | 92.1% | 89.5% |
* SWE-bench Verified scores from swebench.com leaderboard (January 2026). Vendor-claimed scores may differ due to testing configurations.
Pricing & Cost Analysis
Anthropic's 67% price reduction on Claude Opus 4.5 changed the competitive landscape dramatically:
| Model | Input / 1M | Output / 1M | Cached Input | Typical Request |
|---|---|---|---|---|
| Claude Opus 4.5 | $5.00 | $25.00 | $0.50 | $0.375 |
| Claude Sonnet 4.5 | $3.00 | $15.00 | $0.30 | $0.225 |
| GPT-5.2 Codex | $1.75 | $14.00 | $0.175 | $0.158 |
| Gemini 3 Pro | $2.00 | $12.00 | $0.50 | $0.16 |
| Gemini 3 Flash | $0.50 | $3.00 | $0.125 | $0.040 |
* Typical request: 50K input tokens, 5K output tokens
$375
Claude Opus 4.5
$158
GPT-5.2 Codex
$160
Gemini 3 Pro
$40
Gemini 3 Flash
Context Windows & Capabilities
| Feature | Claude Opus/Sonnet 4.5 | GPT-5.2 Codex | Gemini 3 Pro |
|---|---|---|---|
| Standard Context | 200K tokens | 400K tokens | 1M tokens |
| Extended Context | 1M (beta) | 400K | 2M (coming) |
| Max Output | 64K tokens | 128K tokens | 65K tokens |
| Extended Thinking | Yes (visible) | Internal | Internal |
| Code Execution | Via tools | Native | Via tools |
Context in Practice: 200K tokens holds approximately 150,000 words or 40,000 lines of code. GPT-5.2's 400K context handles larger monorepos without chunking, while Gemini's 1M context can analyze entire enterprise codebases in a single request.
Coding Capabilities Deep Dive
Claude Opus 4.5 Strengths
- Extended Thinking: Visible chain-of-thought for complex debugging, showing exactly how it reasons through problems
- Code Quality: Generates cleaner, more idiomatic code with better error handling and documentation
- Security Focus: Superior at identifying vulnerabilities and suggesting secure coding patterns
- MCP Integration: Native Model Context Protocol support for tool use and agentic workflows
GPT-5.2 Codex Strengths
- Native Code Execution: Runs code in sandboxed environment, validates outputs automatically
- Mathematical Reasoning: Perfect AIME 2025 score translates to better algorithm optimization
- 128K Output: Can generate entire applications in single responses
- Codex Agents: Built-in autonomous development with file system access
Gemini 3 Pro Strengths
- 1M Context: Analyze entire large codebases without chunking or summarization
- Multimodal: Understand diagrams, screenshots, and architectural visuals in context
- Google Ecosystem: Deep integration with Cloud, Firebase, and Antigravity IDE
- Flash Speed: Gemini 3 Flash offers fastest inference for high-throughput applications
Agentic & Tool Use Features
All three models excel at agentic development, but with different approaches:
Model Context Protocol enables standardized tool integration across 20+ services
Works with Claude Code CLI, Cursor, and Windsurf
Strong ecosystem after Linux Foundation donation (Dec 2025)
Native agentic capabilities with file system and terminal access
Code execution in sandboxed environment
Deep integration with GitHub Copilot Workspace
Google Antigravity IDE with "Manager View" runs 5 parallel agents
Chrome integration for browser automation
76.2% SWE-bench score on Antigravity platform
Which Model to Choose
Choose Claude Opus 4.5 When:
- Production code quality is paramount - Claude generates cleaner, more maintainable code
- Complex debugging requires visible reasoning - Extended Thinking shows the thought process
- You need MCP ecosystem integration for tool use and agentic workflows
- Security-sensitive applications require thorough vulnerability analysis
Choose GPT-5.2 Codex When:
- You need larger context (400K) for monorepos or extensive documentation
- Native code execution matters for validated, tested outputs
- Mathematical or algorithmic challenges require perfect AIME-level reasoning
- OpenAI ecosystem integration (Copilot, Azure) is already in place
Choose Gemini 3 Pro/Flash When:
- Budget is the primary concern - Flash is 10x cheaper than competitors
- Analyzing massive codebases requires 1M token context
- Google Cloud, Firebase, or Antigravity IDE integration is needed
- High-throughput applications need the fastest inference speeds
Real-World Coding Tests
We tested all three models on common development scenarios:
Claude Opus 4.5
- Time: 4.8s
- Approach: useReducer with batched updates
- Quality: Production-ready, comprehensive
- Extended thinking: Visible reasoning
GPT-5.2 Codex
- Time: 3.2s
- Approach: useRef + cleanup
- Quality: Works, less idiomatic
- Code execution: Validated fix
Gemini 3 Pro
- Time: 3.0s
- Approach: AbortController pattern
- Quality: Good, modern approach
- Context: Full app analysis
Ready to Upgrade Your AI Coding Stack?
Whether you choose Claude, GPT-5.2, or Gemini, our team can help you integrate the right AI models for your development workflow.
Frequently Asked Questions
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