Anthropic's most capable Opus yet, built for long-horizon autonomous agents and frontier coding.
OpenAI's most advanced agentic coding model with 400K context.
No shared demos for these models yet.
No captured outputs for these models yet.
Based on the Capability Index, Claude Opus 4.8 scores higher (89.2 vs 87.0). However, "better" depends on your use case — pricing, speed, context window, and specific capability needs all matter.
GPT 5.3 Codex has a lower blended cost. Claude Opus 4.8: $5.00 input / $25.00 output. GPT 5.3 Codex: $1.75 input / $14.00 output.
Claude Opus 4.8 has a larger context window: Claude Opus 4.8 supports 1M tokens vs GPT 5.3 Codex at 400K tokens.
Yes, both Claude Opus 4.8 and GPT 5.3 Codex support vision/image input.
Claude Opus 4.8 scores higher on SWE-bench Verified: Claude Opus 4.8 resolves 89% vs GPT 5.3 Codex at 75%.
Key differences: GPT 5.3 Codex is significantly cheaper. Compare full specs on this page.
If cost is your priority, choose the cheaper option. If you need the highest intelligence for complex tasks, pick the higher-scoring model. For long documents or codebases, choose the larger context window. You can try both Claude Opus 4.8 and GPT 5.3 Codex for free on idapt.app to see which performs better for your specific needs.