GPT-5.2 Codex vs Claude Fable 5

Detailed comparison of capabilities, features, and performance.

GPT-5.2 Codex

GPT-5.2 Codex

OpenAI
VS
Claude Fable 5

Claude Fable 5

Anthropic
Feature GPT-5.2 Codex Claude Fable 5
AI Lab OpenAI Anthropic
Context Size 400,000 tokens 1,000,000 tokens
Max Output Size 128,000 tokens 128,000 tokens
Frontier Model Yes Yes
Vision Support Yes Yes
Description OpenAI's coding-optimized model built on GPT-5.2. Designed for agentic coding tasks including building projects from scratch, feature development, debugging, large-scale refactoring, and code review. Supports multimodal inputs for UI development. Anthropic's most capable widely released model, with a 1M token context window, 128k max output, and always-on adaptive thinking.

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