Teams keep reaching for a wiki as the source of truth for decisions. It feels right: one place, everyone can edit, everything in a page. Then the questions start, and the wiki goes quiet. A page can hold information without ever answering anyone. A real source of truth needs four things a wiki lacks.
1. It answers a question, not just stores a page
A wiki is built around pages. You go to it already knowing what you are looking for and roughly where it lives. But the person with a decision question rarely knows either. They have a question, not a page name. They want to know what was decided about pricing, not to read the whole pricing space and hope. A source of truth has to meet a question with a scoped answer, not hand back a folder to dig through.
The gap shows up in behavior. When people cannot get an answer from the wiki quickly, they do the faster thing: they ask a person. Every unanswered search becomes an interruption for whoever wrote the page. A place that truly holds the truth has to be faster to ask than a human is, or people will keep asking the human.
2. It records who decided and who approved
Most wiki pages describe what without saying who. They read as if the decision made itself. But half of every real decision question is about people: who made this call, and who signed off? When that is missing, the reader cannot judge how firm the decision is, and cannot go to the right person if it needs to change. A source of truth carries the decider and the approver as plain facts, not something you infer from the page history.
3. It points to a source you can check
A wiki page is often a summary written after the fact, one step removed from where the decision happened. If it is wrong or stale, nothing warns you. A source of truth links back to the thread, ticket, or document where the call was actually made, so a reader can verify it without asking a person. Trust comes from being able to check, not from the page simply asserting something is true.
4. It admits when it does not know
This is the one a wiki cannot do at all. An empty or outdated page looks the same as a correct one. It never tells you it is out of date, so people quote stale pages with full confidence. A source of truth has to draw a line between what it knows and what it does not, and say plainly when the answer is not on record. Silence that looks like an answer is worse than no answer, because someone acts on it.
This is also the hardest need to meet, because it runs against how most tools are built. They are designed to always return something. A real source of truth needs the discipline to return nothing when it knows nothing, and to say so out loud. "I do not have that on record" is a useful answer. A confident page built on a guess is not.
The pattern under all four
A wiki is a filing cabinet. It stores well and answers poorly. The four needs above are all about answering: meeting a question, naming the people, showing the proof, and being honest about the gaps. A place that only files will always send people back to each other for the real answer.
That gap is where StandIn sits. You write one short brief at the end of your day, and while you are off, it answers your teammates from what you wrote, names who decided, links the source, and says so when the answer is not in the record. Not a better filing cabinet. A record that can actually answer.
When you're off, your StandIn is on.
It answers your teammates' questions from work you've already done, in your words, with a source under every answer.