A new mode called "Ultraplan" appeared inside Claude Code on April 4, visible to users on Anthropic's Max 20x subscription. Max 20x is the highest-tier individual Claude plan at roughly $200 per month, providing 20 times the message limits of a standard Pro account.
Anthropic hasn't published documentation or made an official announcement. Users on the Max plan reported seeing Ultraplan appear after updating to the latest Claude Code release.
The name points to an extension of Claude Code's existing plan mode - a feature that separates "thinking through the task" from "executing the task," letting you review the agent's proposed approach before it starts modifying your files. Ultraplan likely takes that further, possibly with more detailed multi-step breakdowns or deeper codebase analysis before execution begins.
The Max 20x restriction at launch suggests the mode is compute-intensive. Claude Code already uses more processing per task compared to standard chat - adding a more thorough planning phase pushes that higher. Keeping it behind the top subscription tier while Anthropic monitors infrastructure load is a reasonable rollout approach.
Claude Code has shipped features quickly since launch, sometimes before official documentation arrives. Whether Ultraplan expands to lower subscription tiers or stays exclusive to Max 20x hasn't been addressed by Anthropic.