o3

At a glance

What o3 does

Vision, Tool use, Extended thinking, Streaming, Structured output

Best for

Hardest coding problems, complex multi-step reasoning, advanced debugging

Works well with

Conflicts & caveats

• Trae's built-in model menu may not include o3 — Trae primarily ships with Claude/GPT/Gemini/DeepSeek.
• Google Antigravity is built around Gemini 3 Pro; Claude and recent GPT-5 models also work, but o3 is not in the supported model list.
• Kiro's spec mode is tuned for Claude models — o3 may work but spec-driven flows are best with Claude.
• Gemini CLI is locked to Google Gemini models — your LLM is o3.
• Claude Code only works with Claude models — your LLM is o3.
• Devin uses Cognition's proprietary model internally — your selected o3 will be ignored.
• OpenAI Codex (Cloud) runs GPT-5.1 Codex internally — your selected o3 will be ignored.
• Jules runs Gemini models internally — your selected o3 will be ignored.
• The Claude Code SDK is tuned for Claude models — o3 may work via the model adapter but loses Claude-specific features (thinking, prompt caching, sub-agents).
• Lovable uses a fixed internal model — your selected o3 will be ignored.
• Replit Agent 3 uses its own model selection internally — your selected o3 will be ignored.