Why this lesson exists. You have three pages the model now trusts completely. That trust is the problem. Lesson 1 noted that the model repeats what it sees with total confidence, right or wrong, current or stale. This lesson is about the habit that keeps a second brain from quietly becoming a liability.
By the end of this lesson you will be able to set up a second brain so that it stays true, because you will have seen how a withdrawn fact survives and then fixed a page so it cannot.
The price that would not die
A company raises its Professional plan from £79 to £99 in March. Someone updates the pricing page on the website and the "What we sell" page in the second brain. Job done.
In June, a customer forwards a quote email that says £79. Confused, the team traces it. The AI draft came from a sales skill built in February, which had the old price pasted into its context paragraph. Nobody had thought to check the skill, because the "real" price lived in the second brain and that had been updated. The model had two sources, one current and one stale, and no way to know which was which. It used the one that was in front of it.
Then, in August, it happens again from a different direction. An old one-pager PDF, still sitting in the shared Library, is attached to a conversation by a well-meaning colleague. £79 again.
Three months of a withdrawn price appearing in live customer correspondence, and the second brain was "up to date" the whole time.
Why this happens, and what prevents it
The model has no sense of time and no sense of authority. A fact in front of it is a fact. So a second brain that is not maintained is not merely less useful than a maintained one; it is actively harmful, because it lends stale facts the confidence of a curated source. This is the reason the "What has changed" page from Lesson 6 exists: it is the only place where a fact can be marked as withdrawn rather than simply missing.
The habits that keep a second brain true are small, and they work because each one attacks a specific way facts go stale:
Every page has an owner and a review date. Monthly for prices and products, quarterly for the rest. Facts go stale because nobody is responsible for them; a name and a date fixes that.
Reference don't duplicate. Always reference resources instead of duplicating the information. "Pricing can be found at...", "Case studies can be found at...". Following this pattern will mean there's less work involved when a fact changes. Meaning you don't need to search everywhere for the old one. The skill from February, the PDF in the Library, the example email in "How we sound". Stale copies survive because nobody looks for them. Keep key information that's referenced across multiple skills and jobs in a single and easy to reference location.
