Keep a prompt library in Obsidian, tagged and versioned

Every reusable instruction in my vault is a note with three lines of frontmatter: tag: prompt, model, and updated. The body is the prompt itself, followed by a short "known failure modes" list.

• Search by tag when you need one.
• When a prompt stops working after a model update, bump updated and note what changed.
• Share the note, not a screenshot of a chat.

The failure-modes list is the part people skip and the part that saves the most time. "Tends to add a summary paragraph nobody asked for" is worth more than the prompt.