Autocomplete

Autocomplete tools (Copilot, Codeium, Supermaven) use LLMs to predict your next few lines of code.

Under the Hood

A system prompt instructs the model: given these files and the cursor position, predict the next snippet. Your code—including comments—becomes the context. The model outputs what it predicts comes next.

Prompting Without Realizing It

You type a comment:

// validate email format and check if domain exists

Autocomplete suggests:

async function validateEmail(email: string): Promise<boolean> {

You weren’t thinking “prompt.” You were documenting. But that comment went into the context, and the model predicted what comes next. The comment—and everything else in the context—was the prompt.