Attach or run: the @ and / split

The @-attaches / -runs mental model

Two characters carry the entire daily-driver grammar of the Agent sidebar, and confusing them is the single most common stumble. Hold one rule and you never confuse them again:

@ attaches context. / runs something.

@ pulls something into the prompt. Type @ in the Agent input and a picker opens; choose a thing and it’s attached as context the agent can see for that turn - a file, a folder, your docs, terminal output, a past chat, a git diff, the browser. It does not do anything. It answers the question “what should the agent be looking at while it works on this?” When you say @importer.ts fix the date parsing here, the @importer.ts is you handing the agent the file so it doesn’t have to go find it.

/ triggers an action. Type / and the picker lists things the agent can run - your custom commands and skills (for example /write-tests or /summarize). / answers “what procedure do I want to fire?” not “what should it read?”

The test that settles every case: am I telling the agent what to look at, or what to do? “Look at” is @. “Do” is /. A prompt routinely uses both - @money.ts @money.test.ts /add-test cover the negative-balance case attaches two files with @ and fires a custom command with / - and once the rule is in your hands you stop thinking about it. We don’t catalogue every @ target or every / command here; that’s the context chapter’s job. What you need today is the split, because it’s the grammar under every prompt you’ll type for the rest of the course.

So you can now aim the agent precisely. What happens after it answers is the half of the loop that keeps you safe. Next: reviewing what it proposes.