We use this custom gitbook plugin for injecting custom Seam stuff into Gitbook, such as Seam Components.
The documentation for Gitbook integrations is not great, you should reference their examples if you're doing development work here. In particular, the mermaidjs integration is very similar You can see logs on the seam-gitbook-plugin integration page under Developer Settings when something fails to render.
We already did this for Seam, don't do it again
npm run publish-integrations-staging will add