Six lines

About this video

Two people on Leila's team ask the same agent for help with the same monthly sales report. One types "Make the report better" and gets a new colour scheme and a rewritten introduction nobody wanted. The other writes six lines and gets exactly what she needed, in half the time. Same model, same tools, same report: the difference was the brief.

Imagine being the agent. You start blank, with only what's in your context: the system prompt, the instruction file, and one line, "Update the sales report for October". Which report? Updated with what? When is it finished? Is anything off limits? An agent fills every gap with a guess, and says it confidently.

A good brief has four parts. The goal, and why: a clear outcome lets the agent choose its own steps well, and the why settles the small things you didn't mention. The context it can't guess: which file, and where the new numbers are. Point to files rather than pasting them, and put facts every session needs in an instruction file such as CLAUDE.md. What done means, in a form it can check: without it the agent stops when its story sounds finished; with it, it knows what to verify before it reports, and you know what to check after. What's off limits: things that must not change and actions it must not take. Words in a brief are followed usually; for anything that must never happen, back them with a permission rule or a hook, which are followed always.

Fit the brief to the job too: ask for a plan first on a big or unclear task, keep one task per session, hand heavy reading to a subagent, and show one example of the output you want. Then read your brief as the agent would, starting blank: every guess you would have to make is a line to add.

Transcript

1. 0:00Two people ask the same agent to help with the same monthly sales report. One writes, make the report better. The other writes six lines. Only one gets what she needed.
2. 0:22Imagine you are the agent. You start blank, with the system prompt, the instruction file, and one line. Which report? Updated with what? When is it done? Every gap gets a confident guess.
3. 0:46So the first part of a brief is the goal, and why. A clear outcome lets the agent choose its own steps well, and the why settles the small things you didn't mention.
4. 1:08Second, the context it can't guess. Which file, and where the new numbers are. Point to files rather than pasting them, and put facts every session needs in an instruction file.
5. 1:30Third, what done means, in a way it can check. Without it, the agent stops when its story sounds finished. With it, it knows what to verify, and so do you.
6. 1:52Fourth, what's off limits. Words are followed usually. For anything that must never happen, add a permission rule or a hook. Rules are followed always.
7. 2:14Fit the brief to the job, too. Plan first for a big task, one task per session, a subagent for heavy reading, and one example of the output you want.
8. 2:38Read your brief as the agent. Every guess is a line to add.