> For clean Markdown of any page, append .md to the page URL. > For a complete documentation index, see https://docs.livingbrain.com/llms.txt. > For AI client integration (Claude Code, Cursor, etc.), connect to the MCP server at https://docs.livingbrain.com/_mcp/server. # Design policies A brain makes four decisions about each fact it extracts. Living Brain makes each one with a **design policy**, a score built from named signals that only counts once the item has passed the policy's checks. * **MWS** decides at the extract stage: Keep it? * **PFS** decides at the route stage: Which page? * **CRS** decides at the connect stage: Link to what? * **RPS** decides at the resurface stage: Bring back when? | Policy | Decides | Scores | | ---------------------------------- | -------------------------------------- | ------------------------------------------- | | [MWS](#memory-worthiness-score) | Whether a fact is maintained in a page | An extracted fact | | [PFS](#placement-fit-score) | Which page the fact goes on | A fact against one candidate page | | [CRS](#connection-resonance-score) | Which pages are linked | A proposed link between two pages | | [RPS](#re-entry-priority-score) | When a page comes back to you | A page, in the context of a task and a time | ## How a policy scores Each policy raises a score for its signals and lowers it for its penalties. The checks run first. An item that fails one is excluded whatever it would have scored, so a page the caller isn't allowed to see never becomes eligible because it is relevant. > **Info** > > The API doesn't return policy scores, and how signals are weighted isn't published. A score orders decisions inside the brain. It is not the probability > that a fact is true. ## Memory Worthiness Score MWS decides how much maintenance a fact gets. | Checked first | Raise the score | Lower the score | | ------------- | ------------------------------------------------------------------------------------------------------------------ | ------------------- | | Eligibility | Durability, impact, recurrence, novelty, expected future use, extraction confidence, relevance to you or a project | Unsuitable material | "Our enterprise plan caps seats at 50" will stay true for a while, is likely to be asked about and belongs to a project, so it lands in **Durable** and is maintained in a page. "Remind me to grab milk" scores low on durability and future use and stays **Source-only**. **Provisional** facts are kept and looked at again as more evidence arrives. A low score deletes nothing. A source-only fact can still be found in its source. The mistake MWS has to avoid is a false exclusion, where a rare fact is skipped today and a question needs it next month. ## Placement Fit Score PFS decides which page a fact goes on. | Checked first | Raise the score | Also compared | | ------------- | --------------------------------------------------------------------------------------------------------------------------------- | --------------------------------------------- | | Eligibility | Meaning match, word match, shared people and things, relationship judgement, time compatibility, graph proximity, routing history | The gap between the best and second-best page | PFS scores the fact against each candidate page and then measures the gap between the top two. "Acme moved its launch to 15 June" and "Apex moved its launch to 15 July" embed almost identically, but they share no customer. The shared-entity and relationship signals keep the Acme fact off the Apex page. The outcome depends on the gap: * **Place**: one page is clearly the best fit. * **Review**: two pages fit almost equally well, so the fact is held rather than forced onto one. * **New location**: no candidate fits. The brain starts a new page and keeps the source evidence. A page that merges two customers reads smoothly and gives wrong answers about both, which is why a small gap goes to review. ## Connection Resonance Score CRS decides which pages are linked as worth reading together. | Checked first | Raise the score | Lower the score | | ---------------------- | ---------------------------------------------------------------------------------------------------------------------- | ---------------------- | | Permission, provenance | Proximity, relational meaning, evidence strength, time relevance, graph evidence, observed usefulness, complementarity | Duplication, staleness | A page on "Postgres LISTEN/NOTIFY limits" and one on "Realtime notifications design" share little vocabulary, yet the first changes how you read the second. That is the test for a **Strong** link. Two pages that say the same thing lose score to the duplication penalty, and a link whose evidence has aged loses score to the staleness penalty. Permission is checked before scoring, so a page is never linked to one the caller can't see. > **Tip** > > The connections the API returns today use a categorical rubric, `strong`, `medium` or `weak`, each > with a written reason. See [Connection](/docs/concepts#connection). ## Re-entry Priority Score RPS decides when a page comes back to you without being asked for. It scores the page against the current task and the current time. | Checked first | Raise the score | Lower the score | | ------------------------- | ------------------------------------------------------------------------------------------------------- | --------------- | | Permission, current state | Task fit, connection strength, urgency, open commitments, recurrence, impact, affinity, new information | Fatigue | "Send Acme the security review by Friday" scores high on urgency and open commitments, so it can trigger a **Notification** or appear in the **Daily brief**. A preference mentioned once months ago sits in **Quiet context**, where an agent can use it without interrupting anyone. Fatigue lowers the score of anything shown repeatedly and ignored. **Action-affecting** means the page should shape what an agent does next. It does not give the agent permission to act. ## How the four depend on each other Each policy works on what the one before it produced. If extraction gets a fact wrong, placement puts the wrong fact on the right page. A connection only helps when retrieval follows it, and ranking can still drop a premise that earlier stages kept. The scores measure different objects, so an MWS of 0.8 and an RPS of 0.8 can't be compared, and no single number combines them. For the state of a whole brain, see [Brain health](/docs/brain-health).