The rule
Every fact has exactly one canonical home. The knowledge vault holds durable truth. Session memory holds current state. Skills hold repeatable procedure. Anything written twice will eventually disagree with itself — and an agent reading the stale copy will act on it.
When to run it
Set it up once; enforce it every session. Audit quarterly for drift.
The play
1. Vault (canon): company facts, pricing, decisions, architecture. Human-readable markdown, linked, with an index note agents read first. 2. Memory (state): what's in flight, what's blocked, what changed lately — timestamped, superseding entries kept in order, so a fresh session reconstructs reality in one read. 3. Skills (procedure): the how-to for recurring jobs — deploy steps, brand rules, hard guardrails ("never use X footage", "never auto-publish"). 4. End every significant session by filing: durable facts to the vault, state changes to memory, new procedures to skills. 5. When sources conflict, canon wins, and the loser gets corrected immediately.
Where it breaks
Frozen archives treated as live truth, "I'll file it later," and secrets in notes — credentials live in secret managers, never in the brain.