GPT-6 Sol vs Claude Opus 5.5: Coding, Pricing, and AI Agents

GPT-6 Sol and Claude Opus 5.5 introduced on September 22, 2026, now compete in the API pricing, coding performance, reasoning controls, and agent workloads sectors. OpenAI priced GPT-6 Sol at $2 per million input tokens and $10 per million output tokens, whereas Claude Opus 5.5 costs $4 per million input tokens and $20 per million output tokens.

Sol's advantage lies in its lower uncached input and output price, while Opus 5.5 leads several coding benchmarks. The models differ in reasoning controls, deployment options, and safeguards. Factors like context usage, reasoning needs, and whether coding or automation is prioritized determine the better fit. The 272,000-token threshold affects pricing, with Sol charging the same rate as Opus 5.5 for longer requests.

Context windows and output limits are identical for both models at 1 million tokens, with Opus 5.5 offering an additional 300,000 tokens via the Message Batches API. Reasoning options vary between Sol's customizable levels and Opus 5.5's always-on adaptive thinking. Benchmarks show Opus 5.5 leading in certain coding and agent tasks, but real-world production results require testing against specific repositories.

For agent workflows, models with higher token prices may still be cost-effective if they complete tasks efficiently. OpenAI and Anthropic tailor their respective models for coding and agentic work, with Anthropic offering Opus 5.5 at about 40% lower costs than Opus 5 on typical token-billed workloads. Both models are available through various platforms, including OpenAI's API, Amazon Bedrock, and Google Cloud.