GPT-6 Luna vs Claude Haiku 5.5

GPT-6 Luna in brief

GPT-6 Luna specs and pricing: OpenAI's lowest-cost GPT-6 model (September 2026) at $0.10/$0.50 per million tokens with a 1.05M-token context window.

• Very low price
• Fast responses
• Same ~1.05M-token context as the rest of the GPT-6 family

Claude Haiku 5.5 in brief

Claude Haiku 5.5 specs and pricing: Anthropic's fastest model (October 2026), from $0.10/$0.50 per million tokens with a 1M-token context, vs GPT-6 Luna.

• Fastest model in Anthropic's lineup
• From $0.10 / $0.50 per million tokens
• 1M-token context and 128K output
• Adaptive thinking with adjustable effort

GPT-6 Luna or Claude Haiku 5.5: which should you choose?

GPT-6 Luna is best for:

• Classification, extraction and routing at scale
• Chat features in consumer apps
• Sub-agents inside larger agent systems

Claude Haiku 5.5 is best for:

• Classification
• extraction and routing at scale
• Sub-agents inside larger agent systems
• Latency-sensitive features in apps

For most teams the best test is your own workload: run the same 20–50 real prompts through both models and compare quality, speed and cost. Benchmarks published by labs use different settings and rarely match everyday use.