Head-to-head

GPT-5.6 Sol vs Claude Opus 4.8

How GPT-5.6 Sol (OpenAI) and Claude Opus 4.8 (Anthropic) compare on price, context window and best-fit use case.

In short: GPT-5.6 Sol is best for the highest-stakes reasoning, deep agents and frontier coding where capability outweighs cost, while Claude Opus 4.8 suits complex coding agents, long-horizon tasks, and workloads needing top reliability and reasoning. On price it's $5.00 vs $5.00 per 1M input tokens; on context, ~1M tokens (128K max output) vs 1M tokens.

Verdict

GPT-5.6 Sol is the more capable pick (Bq score 96 vs 93). Choose Claude Opus 4.8 if its fit is closer to your workload: complex coding agents, long-horizon tasks, and workloads needing top reliability and reasoning.

SpecGPT-5.6 SolClaude Opus 4.8
DeveloperOpenAIAnthropic
Context window~1M tokens (128K max output)1M tokens
Input price /1M$5.00$5.00
Output price /1M$30.00$25.00
Modalitiestext, imagetext, image
Best forThe highest-stakes reasoning, deep agents and frontier coding where capability outweighs cost.Complex coding agents, long-horizon tasks, and workloads needing top reliability and reasoning.

GPT-5.6 Sol

  • Frontier reasoning and agentic workflows
  • New Ultra subagent + Max reasoning modes
  • ~1M context window
  • Strong coding and tool use
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Claude Opus 4.8

  • Best-in-class coding and agentic tasks
  • Adaptive reasoning with effort controls
  • 1M context at flat rate
  • Strong instruction following and safety
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