Build the judgement before the automation.
A brief is a decision document. Its job is to hold the promise steady while everything downstream — script, visuals, edit, title — changes ten times. Without one, the video quietly becomes whatever was easiest to make that week.
Start with the viewer's current situation and the change you are offering. Not the topic. 'A video about soil testing' has no tension; 'you are about to spend money on fertiliser and do not know if you need it' has a viewer with a decision to make and a reason to keep watching.
The tension explains why now, and the proof explains why you. Proof is what you can show that a summary could not: your own footage, your own numbers, a named source you opened, a person you actually spoke to. A video with tension and no proof is content; with both, it is worth someone's time.
Packaging starts in the brief because title, thumbnail and opening line all promise the same thing. Write the title territory before the script and you will notice immediately if the video cannot deliver it — which is far cheaper than noticing after the edit.
The exclusion list is the most useful section and the one people skip. Naming what the video will not cover prevents scope creep, prevents generic padding, and gives you a ready answer to the comment asking why you did not mention something.
Define success before publishing, and make it something other than views. 'Three people say this changed what they did' is a result you can learn from. Views tell you the packaging worked; they tell you nothing about whether the video did.