Anthropic’s fix for Fable 5’s high cost is turning it into a manager that delegates to Sonnet 5

Anthropic recommends using the expensive Claude Fable 5 mainly as a planner for smaller models instead of running it on every task. Combined with Sonnet 5 in the “Advisor” pattern, this setup hits 92 percent of Fable 5’s solo performance at 63 percent of the cost.

In the “Advisor” pattern, Sonnet 5 runs as the executor and only calls Fable 5 when it needs guidance. On SWE-bench Pro, this combo reaches about 92 percent of Fable 5’s solo performance at 63 percent of the cost, according to Anthropic. Fable 5 gets called roughly once per task. In the second pattern, Fable 5 acts as a planner that delegates tasks to Sonnet 5 worker agents. On BrowseComp, this delivers 96 percent of Fable 5’s performance at 46 percent of the cost. Both patterns run through Claude Managed Agents, with each sub-agent using its own cache to avoid duplicate context costs. The official documentation has more details. Anthropic is likely sharing these tips because of growing price pressure. Chinese open-source models are already undercutting Western pricing, and the new GPT-5.6 Sol is much cheaper per token and reportedly more token-efficient too.AdDEC_D_Incontent-1Ad Follow The Decoder for AI news, background stories and expert analyses.