GPT-5.2 Codex vs Claude 4.5 Haiku

1. Optimized for Long-Horizon Coding Tasks

• OpenAI describes GPT-5.2 Codex as a highly intelligent coding model built for long-horizon, agentic coding work.
• Well suited to planning, refactoring, debugging, and multi-step implementation flows inside real codebases.

2. Adjustable Reasoning for Coding Work

• Supports configurable reasoning effort from low to xhigh depending on speed and quality needs.
• Accepts both text and image inputs while producing text output.

3. Large Context + Long Output

• 400 k token context window supports broad repository understanding and larger working sets.
• Allows up to 128 k output tokens for longer patches, code generation, and technical explanations.

4. Up-to-Date Model Snapshot

• Knowledge cut-off of Aug 31 2025 keeps it current with newer tools and frameworks.
• Supports streaming, function calling, and structured outputs for tool-driven coding workflows.

1. Frontier-level coding at small-model speed

• Similar coding performance to Claude Sonnet 4 at one-third the cost.
• Runs 4-5x faster than Sonnet 4.5 for many tasks.
• Ideal for real-time pair programming, prototyping, and rapid iteration.

2. Excellent computer-use abilities

• Surpasses Claude Sonnet 4 in certain computer-control tasks.
• Great for agents requiring low-latency tool use (Chrome automation, coding agents, etc.).

3. Perfect for real-time, low-latency applications

• Chat assistants
• Customer support agents
• Interactive development loops
• Multi-agent orchestration

4. Works seamlessly with Sonnet 4.5 in hybrid agent setups

• Sonnet 4.5 plans complex workflows.
• Haiku 4.5 executes subtasks in parallel for speed and cost-efficiency.

5. High alignment & safest Claude model by metric

• Lower misaligned behavior rates than Haiku 3.5, Sonnet 4.5, and Opus 4.1.
• Limited CBRN risk → released under AI Safety Level 2 (ASL-2).