Ultrathink is a Claude Code a magic word

a year ago

Anthropic's Claude Code CLI tool recommends using specific phrases like 'think', 'think hard', 'think harder', and 'ultrathink' to trigger extended thinking modes.
Each phrase ('think' < 'think hard' < 'think harder' < 'ultrathink') allocates progressively more computation time for Claude.
The 'ultrathink' phrase is particularly notable, mapping to a token budget of 31,999 in the Claude Code system.
Analysis of obfuscated JavaScript in Claude Code reveals that phrases like 'think harder' and 'ultrathink' directly influence token allocation.
Other phrases like 'megathink' map to 10,000 tokens, while 'think' alone maps to 4,000 tokens.
Claude Code's behavior is confirmed through code examination, showing it's a feature of the tool rather than the base Claude model.

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