What is Expand mode?
Expand mode grows a paragraph to roughly 1.5× its length by adding supporting detail to the points you already made. The expansion target is 130-170% of input length depending on how much room the original left. What gets added: examples, qualifying clauses, concrete specifics, second-order implications. What doesn't get added: the same sentence rewritten three times, filler transitions, throat-clearing phrases, or made-up facts dressed up as support.
This is the mode to pick when the paragraph is too thin. The points are right but the prose feels skeletal — readers will skim past it because there's nothing to slow them down. Expand fleshes out those points with the kind of detail you'd add yourself given more time. The output reads like a denser version of your paragraph, not a longer one.
When to use Expand mode
The most common case: hitting a word count from below. Your essay is 900 words and the minimum is 1,200, and several paragraphs are doing too little work. Run the thinnest one through Expand at Medium strength and you'll get three versions that fill out the points you made. Pick the one that fits the surrounding voice, paste it back, recheck the count, and move to the next thin paragraph.
Other good fits: developing a section of a blog post that reads rushed, fleshing out a methods or background section that assumed too much reader knowledge, growing an FAQ answer that's too brief to satisfy the question, adding substance to executive summary bullets that need to become full paragraphs.
Expand is the wrong call when your paragraph isn't actually thin — it's just unclear or stiff. The fix there is Standard or one of the register modes. For wording changes that don't grow the paragraph, the paraphrasing tool is closer to what you want.
How Expand mode compares to other modes
Expand is the only mode that aggressively grows length. The four register modes preserve length; Shorten cuts it.
The risk people worry about — that expansion is just padding — is the failure mode Expand is tuned to avoid. The cheap version of growing a paragraph is restating each sentence in a slightly different way, which doubles word count and adds zero substance. Expand reaches for new material instead: a concrete example, a qualifying condition, an implication. The output is longer because there's more in it, not because the same content is spread across more words.
Subtle Expand grows roughly 1.2×. Medium hits 1.5×. Aggressive can push to 2× but starts to risk repetition past that point. If you need much more length, write the second paragraph yourself instead of expanding one beyond what its points support.