Positioning is an internal document. Foundations is explicit about this, and it is the part people most often skip. The document says what market problems the product solves, for which personas, against which alternatives, and with what evidence. Everything the market sees, web copy, decks, campaigns, sales conversations, is derived from it.
Written from problems, not features
The discipline is the same one that produced the market problems table. Each positioning claim starts from a problem that has been validated as urgent and pervasive, and states how the product removes it. The feature is the reason the claim is credible, not the claim itself.
The test is whether a reader outside the company could tell what changes for them without knowing what the product does mechanically. A page that lists capabilities passes the internal review and fails that test.
Against which alternatives
Positioning only exists relative to something. The alternatives include competitors, the internal build, the incumbent tool and doing nothing, which is the most common winner. Win and loss interviews supply the real list, which routinely differs from the one the company assumes.
Naming the alternative also sets the category the buyer places you in, and the category sets the criteria they will judge you on. This is the most consequential and least deliberate choice most products make.
From positioning to messages
Once the internal document exists, messages are written per persona. Same product, same underlying claims, different emphasis and different evidence.
The economic buyer wants the business consequence and proof it is real. The technical evaluator wants to know how it works and what it will cost to run. The end user wants to know what changes on Monday morning. A message that tries to carry all three arrives as a paragraph nobody finishes.
Keeping it honest
Positioning drifts, usually toward whatever the product team most recently built. Two checks hold it in place. Every claim should trace to a validated market problem, and every claim should be one a customer would recognise as describing their own situation. Claims that survive only inside the building are the ones that make a sales team quietly stop using the deck.