TIL how to add custom icons to callouts in obsidian. The quickest way is to provide an icon name found at https://lucide.dev , for example with the https://lucide.dev/icons/bot icon bot, including the following in a custom css file in /path/to/vault/.obsidian/snippets:

/* in   /vault_root/.obsidian/snippets/custom-callouts.css */
.callout[data-callout="ai"] {
    --callout-color: 192, 77, 88;
    --callout-icon: bot;

Then enable this in the Obsidian Settings > Appearance > CSS Snippets

Note it won’t work with Obsidian Publish

Aside: I’m using it to create callouts for AI/LLM generated content that I include in my notes, so I know that I may need to verify the truthfulness of the statement later, such as in POP to PC vs BX instruction.