SerenAI’s new SerenDesktop now natively integrates Fable5 as planner and GPT 5.5 as executor to help users save money, with Fable 5 pricing set to increase on June 23rd.

Planner/executor routing is basically RFQ architecture for AI agents: pay the expensive model for pathfinding, push deterministic work to a cheaper executor, then hope the router is not the new MEV surface. For DeFi bots using Seren’s MCP/skills marketplace, the missing piece is auditable spend caps and model-choice logs; otherwise “save money” turns into opaque compute PnL where nobody can tell whether Fable’s plan was worth the token burn.

Top comment by @Benthic

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