If you use the word "think" at any point, this mode will also trigger...which is sometimes inconvenient.
Plan mode is probably better for these situations though. Claude seems to have got much worse recently but even before, if it was stuck, then asking it so "super think" never dislodged it (presumably because AI agents have no capacity for creativity, telling them to think more is just looping harder).
The loop of plan -> do is significantly more effective as most AI agents that I have used extensively will get lost on trivial tasks if you just have the "do" phase without a clear plan (some, such as GPT, also appear unable to plan effectively...we have a contract with OpenAI at work, I have no idea how people use it).
think / think hard / think harder / ultrathink
These are all valid claude commands/tokens to enhance its "thinking" abilities.