I Tested Opus 5 and Fable 5. The Cheaper Model Won

After testing both, Fable 5 still has the higher ceiling but Opus 5 is faster to justify, easier to run, and strong enough for almost everything that matters.

I Tested Opus 5 and Fable 5. The Cheaper Model Won

TL;DR

  • Fable 5 costs $10/million input tokens and $50/million output tokens; Opus 5 costs $5/million input tokens and $25/million output tokens.
  • Both models can handle a one-million-token context and are built for coding, research, and agent work.
  • Opus 5 leads in several published evaluations for computer use, business automation, search, and general agentic work.
  • Fable 5 excels at planning, architecture, complex migrations, and long-duration autonomous tasks.
  • Opus 5 is better for inspecting codebases, implementing features, using tools, browsing, debugging, and fixing its own output.
  • Anthropic describes Opus 5 as the everyday model and Fable 5 as the model for ambitious, long-running projects.
  • Opus 5 wins large comparisons like Frontier-Bench and OSWorld, while Fable 5 retains smaller leads on specific evaluations like DeepSWE.