GPT-5.5 vs Claude 4.5 Haiku

1. Strongest Agentic Coding Model

• State-of-the-art on Terminal-Bench 2.0 (82.7%), Expert-SWE (73.1%), and SWE-Bench Pro (58.6%), outperforming GPT-5.4 on complex coding tasks.
• Holds context across large systems, reasons through ambiguous failures, and carries changes through surrounding codebases with fewer tokens.

2. Higher Intelligence at GPT-5.4 Latency

• Co-designed, trained, and served on NVIDIA GB200/GB300 NVL72 systems to match GPT-5.4 per-token latency while performing at a significantly higher level.
• Uses fewer tokens to complete the same tasks, making it more efficient as well as more capable.

3. Powerful for Knowledge Work & Computer Use

• Scores 84.9% on GDPval (44 occupations) and 78.7% on OSWorld-Verified for autonomous computer operation.
• Excels at generating documents, spreadsheets, and reports; naturally moves across finding information, using tools, and checking output.

4. Scientific Research Co-Scientist

• Leading performance on GeneBench, BixBench, and FrontierMath; helped discover a new proof about Ramsey numbers verified in Lean.
• Strong enough to meaningfully accelerate progress at the frontiers of biomedical and mathematical research.

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).