OpenAI GPT-5.3 Codex vs Claude Opus 4.6: The AI Coding War is Declared
On February 5, 2026, OpenAI and Anthropic launched their new models minutes apart. This isn’t a coincidence — it’s a declaration of war.
On one side, GPT-5.3 Codex transforming Codex into an agent capable of “doing almost everything a developer does on a computer”. On the other, Claude Opus 4.6 finding 500 zero-days and opening the vibe working era.
Here’s what this means for us.
GPT-5.3 Codex: from autocompletion to autonomous agent
OpenAI no longer positions Codex as a coding tool. They position it as an autonomous developer agent capable of:
- Creating “complex games and applications from scratch in days”
- Navigating entire codebases
- Executing multi-file modifications
- Iterating with minimal human input
- 25% faster than the previous model
The shift is clear: moving from “AI that helps you write code” to “AI that develops for you while you supervise”.
Claude Opus 4.6: depth over speed
Anthropic plays a different card. Opus 4.6 isn’t sold on execution speed but on analysis quality:
- 500+ zero-day vulnerabilities detected natively
- 1M token context window in beta
- Better at planning, code review, and debugging
- Ability to extract insights from large document sets
- Professional-grade financial analysis
Where GPT-5.3 Codex says “I code for you”, Opus 4.6 says “I understand your code better than you”.
The real comparison: two philosophies
| GPT-5.3 Codex | Claude Opus 4.6 | |
|---|---|---|
| Positioning | Autonomous agent, execution | Deep analysis, understanding |
| Strength | Speed, autonomy | Quality, security, context |
| Business model | Ads (ChatGPT Go) + API | Ad-free, API only |
| Coding agent | Autonomous Codex | Claude Code + Agent Teams |
| Security | Standard | 500 native zero-days |
| Context | Large | 1M tokens beta |
This isn’t just about benchmarks. It’s two visions of development’s future:
- OpenAI bets on autonomy: AI does the work, you validate
- Anthropic bets on collaboration: AI understands and you orchestrate together
And the others? The complete battlefield
Google Gemini 3 Pro + Deep Research
Google isn’t sitting idle. Gemini Deep Research, powered by Gemini 3 Pro, moves from “specialized research assistant” to autonomous research agent. Long-form reasoning, complex analysis — Google plays the analytical intelligence card.
DeepSeek V4: the Chinese wildcard
DeepSeek is preparing V4 for mid-February 2026, specifically targeting long and complex code. Their previous models already rivaled GPT-5 — and they’re free. DeepSeek also announces a multimodal AI search engine (text, images, audio) to challenge Google directly.
Coding tools: Cursor, Cline, Copilot
The AI coding tool market is exploding:
- GitHub Copilot: 20M users, 90% of Fortune 100
- Cursor: the serious challenger to Microsoft, superior polish and UX
- Cline: the choice for developers who want control (native VS Code, multi-provider, agent workflows)
- Claude Code: CLI + Agent Teams approach for devs who want to orchestrate
85% of developers now regularly use AI tools for coding. It’s no longer a competitive advantage — it’s the baseline.
Legacy model retirement: the end of an era
OpenAI retires GPT-4o, GPT-4.1, GPT-4.1 mini, and o4-mini from ChatGPT on February 13, 2026. Models that seemed revolutionary 18 months ago are already obsolete.
The obsolescence rate is brutal. If you build tools around a specific model, multi-provider abstraction is no longer a luxury — it’s a necessity. That’s exactly the approach of GLM Delegator: your experts work with any provider (Anthropic, OpenAI, Ollama, GLM via Z.AI).
What this changes for your workflow in 2026
1. Don’t bet on a single provider
Models change every 3 months. Your architecture must be provider-agnostic. Use MCP abstractions or multi-provider tools.
2. Orchestration is the new key skill
Knowing how to write code isn’t enough. Knowing how to orchestrate agents that write code — that’s the 2026 skill. Claude Code Agent Teams are the beginning.
3. Native AI security is arriving
With 500 zero-days found by Opus 4.6 and tools like GLM Delegator exposing security experts, automated code auditing is no longer nice-to-have.
4. Free disrupts everything
DeepSeek V4 free + local Ollama = near-equivalent capabilities to proprietary models for zero dollars. The barrier to entry has never been lower.
The war is declared. And developers who know how to orchestrate these tools are the big winners.
Kevin De Vaubree
Senior Full-Stack Developer