My repos all had the same problem. The social preview was either GitHub's auto-generated card or a template that looks like every other template. repo-cover is an agent skill that has the agent design the card. There is no image model. The agent writes one 1280x640 self-contained HTML file, and the design taste lives in hard numbers it cannot drift from. A 4px grid, one accent color darkened until it passes WCAG contrast, title size tiers by name length, a 110 character description budget. A stdlib Python checker verifies canvas, self-containment, contrast, and CJK line breaking, and the agent repairs failures before you ever see them. Four moods ship with it. Editorial, poster, blueprint, gallery. The accent comes from your primary language color, the corner arcs and plate numbers are seeded by your repo name, so no two cards match. Korean, Japanese and Chinese are first class, with real line breaking rules and Noto stacks, not tofu fallbacks. Honest numbers. Eight shipped examples all pass the checker in CI. Two independent agents ran the installed skill cold and both cards passed on the first try. Their friction reports became eleven documentation fixes before launch. And this repo's own social preview is output from the skill. Install with npx skills add sjh9714/repo-cover, then ask your agent for a social preview card. Live gallery with view-source at sjh9714.github.io/repo-cover

repo-cover

Your repo's social preview, designed by your coding agent

Your repo's social preview, designed by your coding agent