What should be in a YouTube description?
Lead with one or two sentences that restate the video's promise and include your main keyword — that's the part visible before the fold and in search. Then add a fuller summary, relevant links, timestamps if useful, and a clear call to action.
Does the description affect YouTube SEO?
Yes. The description helps YouTube understand what your video is about and can influence which searches and suggested feeds it appears in. The first lines matter most, since they're indexed and shown as the snippet.
How long should a YouTube description be?
YouTube allows up to 5,000 characters, but you don't need to fill it. A focused description — strong first two lines, a clear summary paragraph, then links and extras — beats a wall of keyword-stuffed text.
Can I reuse descriptions across videos?
Reuse your boilerplate block (links, socials, channel pitch), but write the first paragraph fresh for each video so it matches the specific topic — that's the part that does the SEO and click-confirmation work.