Lead with the goal
Start with one sentence that says what you want to exist at the end. "A clean list of every supplier invoice from October, matched to its purchase order, in the Reconciliation sheet" gives the agent a target it can check itself against.
Name the sources and the destination
Say where the information lives and where the result should go. Mention the app, the folder, the tab or the view. Agents that work through the screen can find their way around, but naming the place removes ambiguity.
State the rules that matter
Every task has a few non-negotiables. Write them down plainly.
- Boundaries: "Do not send anything; leave drafts for my review."
- Conventions: "Name files with the client name, then the date."
- Edge cases: "If an invoice has no purchase order, add it to a separate list."
- Stop points: "Ask me before changing anything marked Final."
Describe done
Tell the agent how to know it has finished and what you want to see at the end. A short summary of what changed, a list of exceptions and a link to the result make review fast.
Let memory carry the repetition
If you find yourself repeating the same preference in every instruction, save it once as a standing preference. Agents with long-term memory will apply it automatically, and your instructions can stay short.
Iterate like an editor
When a result is not quite right, resist the urge to start over. Note what was missing, add one sentence to the instruction and run it again. Two or three rounds usually produce an instruction you can rely on for months.