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What schemas unlock

Most note-taking apps treat every page the same. You write something, it goes in a pile, you search the pile with text matching. Tags help, but tags are flat. After a few thousand pages, the pile gets noisy and the search gets stupid. Schemas are how modusbrain stops being a pile of notes and becomes something with structure. A schema declares what KINDS of things live in your brain (person, company, meeting, researcher, case, lab-result), what they link to (attended, authored, prescribed-by), what facts the system should extract automatically (mrr=50000, damages=5000000), and which types route through expert search vs general search. The default schema (gbrain-base) ships with 22 page types covering the universal shapes — people, companies, meetings, notes, daily, calendar events. That’s enough to start. But your brain is yours, and your brain’s shape is not the default shape. A research brain needs researcher and paper as first-class types. A founder brain needs lead, investor, portco, deal-stage. A lawyer brain needs case, motion, deposition, precedent. Same engine, totally different shape. v0.40.7.0 made it possible for AGENTS to author that shape for you. Not just “the user manually edits YAML in ~/.modusbrain/schema-packs/mine/pack.yaml” but “your agent sees the corpus, proposes a type, asks for approval, applies it atomically with a full audit trail, then backfills 4000 existing pages with one chunked SQL command.” That’s the new thing. This doc is the WHY. The tutorial is the HOW.

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Killer use cases

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1. The 4000 invisible pages

You have 4000 markdown files under meetings/ going back two years. The default schema doesn’t have a meeting type, so all 4000 are typed note (the catchall). When you run:
You get the top 10 text matches, ranked by raw relevance. The brain has no idea these are meetings. It can’t route to attendees. It can’t pull dates. It can’t surface “this conversation came up again with the same people three weeks later.” Add a meeting type:
The sync backfills page.type = 'meeting' on all 4000 pages in 1000-row batches. Now:
  • modusbrain whoknows "Q3 roadmap discussion" routes through the meeting type, ranking by expert_routing signal (attendees, recency, salience) instead of raw text.
  • modusbrain extract-facts runs on every meeting page automatically (because extractable: true), pulling typed facts like attended_by=alice-example, date=2026-05-23.
  • The downstream think skill can now answer “what did we decide about pricing in the last three roadmap meetings” by querying the meeting graph instead of grep’ing 4000 files.
One command. 4000 pages went from invisible to queryable. The content didn’t change. The structure did.

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2. The founder ops brain

You’re a founder or investor with ~500 markdown files mixing leads, portfolio companies, deal notes, intros, and follow-ups. You’ve been writing freely; you have no system. Your queries are all “wait, who introduced me to that fintech founder again?” and you scroll Notion for 20 minutes. Add the founder shape:
Now modusbrain whoknows "Series A SaaS" routes through investor and portco types specifically, not the noisy general type set. modusbrain graph-query alice-example --type intro-from --depth 2 walks two hops of intros to surface “Alice introduced you to Bob who introduced you to Charlie.” modusbrain extract-facts starts producing typed claims from the fence in your deal pages: (deals/acme-seed, raise=2000000, valuation=15000000, lead=widget-vc, closed_at=2026-05-23). The CRM you’ve been promising yourself you’ll set up next quarter? You just shipped it in 4 commands. It’s downstream of your notes, not parallel to them.

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3. The research brain

Replace “founder” with “PhD student” and the same pattern applies with different types: researcher, paper, lab, grant, dataset + authored, cites, funded-by, uses-dataset.
Suddenly “show me papers that cite this work AND use the same dataset” is a modusbrain graph-query traversal, not 30 minutes in Google Scholar. The fact extraction picks up arxiv_id=2402.04253, cited_by_count=140, published_date=2026-02-15 automatically. Your reading-list-as-markdown turns into a queryable research graph that knows who works on what and what’s connected to what. Lawyers, medical providers, accountants, anyone working in a domain where the meaning of a number depends on its type. A “judgment of 5M"againsta"5M" against a "2M case strategy threshold” is a comparison the brain can do — but only if both numbers are typed.
Now ## Facts fences in your case notes can carry typed claims (damages=5000000, filed_date=2026-05-23, judge=jane-doe) that modusbrain stores as first-class columns. modusbrain eval trajectory legal/cases/acme-v-widget prints the case history with regressions flagged. modusbrain founder scorecard (renamed for legal: roll up plaintiff success rate, average damages, settlement-vs-trial ratio) gives you a structured view of how your practice is performing. This isn’t possible without typed page kinds. You can write the same prose in any note-taking app. Only modusbrain treats the numbers as comparable across pages of the same type.

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5. The team brain

modusbrain mounts add lets you stack additional brains alongside your personal one. Each mounted brain has its OWN schema pack. The eng team’s brain has incident, runbook, service, oncall-rotation. The design team’s brain has component, experiment, ab-test, figma-link. The legal team’s brain has cases and depositions. When you query, the schema pack governs how each source’s content is routed. An eng query against the mounted eng brain knows that incidents/2026-05-23-db-outage.md is an incident page with severity=p0, mttr=47min, on_call=alice-example — extractable typed facts. Your personal query against the same brain still works, but the routing is sharper because the eng team has invested in their ontology. The schema is the team’s tribal knowledge made explicit. Two engineers on different teams searching the same brain get DIFFERENT routing because their personal packs declare different expert types.

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6. The “agent co-curates your ontology” pattern (the new thing)

This is what v0.40.7.0 actually enabled, and what the closed PR #1321 was reaching for. Your OpenClaw (or any agent connected to your brain over HTTPS MCP with admin scope) watches your ingestion stream. After a week of you dumping notes under shubham/companies/w24/, the agent runs modusbrain schema detect periodically, sees that prefix accumulating, and proposes:
You have 47 pages under companies/w24/ typed as company (generic). They share a structural pattern (founder names, raise amounts, batch tag). Should I add a w24-company type with extractable: true and the existing aliases pointing back to company? I’d backfill the 47 pages and add cohort=W24 as a typed fact extracted from each page.
You approve once. The agent calls schema_apply_mutations over MCP with a batch:
All inside ONE withPackLock scope, atomic, audited (the agent’s client_id captured in the audit log as actor: mcp:<clientId8>). Cache invalidated cross-process. Sync backfills the 47 pages. The brain learned a new category of thing without you having to think about it. The next time you query “W24 companies in fintech”, the brain routes through the new type. Six months later when you forget the pattern entirely, the agent reminds you it’s there and offers to consolidate it with the W25 batch. The brain learns. The agent is the curator. You approve, the agent does the work.

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7. The before-vs-after benchmark

If you want to FEEL the difference without buying the pitch: Pick a real corpus you have. Run modusbrain whoknows on a topic that should match. Note the top-3 results. Then run modusbrain schema review-orphans --limit 50 --json and look at the untyped pages. If 10+ of them share an obvious prefix that should be a real type, add the type + sync. Re-run the same whoknows query. Top-3 should shift, because the new type is now routing through expert ranking instead of being lumped into the catchall. The numerical delta IS the win. You can run a tutorial in 5 minutes; this experiment proves it matters on your actual content.

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Why this matters

Three things modusbrain does that generic note systems can’t: 1. The brain knows the difference between a person and an idea. Page-type matters at query time. modusbrain whoknows only considers expert_routing: true types. modusbrain extract-facts only runs on extractable: true types. modusbrain graph-query walks declared link verbs. None of that works on a flat tag system because tags don’t have semantics — they’re labels. Types are first-class citizens with rules attached. 2. Untyped content is invisible content. If your meetings are typed as note, expert routing skips them, facts extraction ignores them, link inference doesn’t fire. They exist on disk and they’re indexed for text search, but the structural surfaces (whoknows, find_experts, recall, think) treat them as second-class. Adding a type isn’t cosmetic; it’s structural promotion. 3. The schema is queryable AND mutable AND auditable. You can ask the brain what its schema looks like (modusbrain schema graph), evolve it through 14 atomic CLI verbs + 9 MCP ops with full lock + audit semantics, and recover from any mistake (every primitive has an inverse, plus modusbrain schema downgrade restores the previous active pack). This isn’t “vibes-based knowledge management.” It’s a production system with structural integrity guarantees.

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What changed in v0.40.7.0 specifically

v0.39.1.0 shipped the schema-pack engine. You could ALREADY fork the bundled pack and edit pack.yaml by hand. What you couldn’t do was let an agent author it safely — there were no atomic file locks, no audit log, no MCP exposure, no pack-aware wiring in the query path. The cathedral was built but unreachable from the outside. v0.40.7.0 closed those gaps:
  • withMutation skeleton wraps every primitive in 8 ordered safety steps (bundled-guard → lock → read → mutate → validate → atomic write → audit → invalidate). The pack file on disk is never partial. Two concurrent agents can’t race.
  • Per-pack O_CREAT|O_EXCL atomic lock (not the TOCTOU existsSync+writeFileSync pattern from page-lock.ts — codex caught that during plan review). TTL refresh every 10s while a mutation runs; --force means “steal stale lock” not “skip locking.”
  • Privacy-redacted audit log at ~/.modusbrain/audit/schema-mutations-YYYY-Www.jsonl. Type names sha8-hashed, prefixes truncated to first segment only. A leaked screenshot of the audit can’t reveal sensitive taxonomy like personal/oncology/ or legal/depositions/.
  • 9 new MCP ops including the batched schema_apply_mutations (admin scope, NOT localOnly — your OpenClaw and any remote agent author packs over normal HTTPS MCP, with client_id captured as actor: mcp:<clientId8>).
  • T1.5 wiring finally completes for whoknows and find_experts: a custom researcher type marked --expert now actually surfaces in query results. Pre-v0.40.7 it silently never matched because the query path read hardcoded ['person', 'company'].
  • Cross-process invalidation via stat-mtime TTL gate inside loadActivePack. Operator runs modusbrain schema add-type from a terminal; the autopilot daemon picks up the new type within 1 second without a restart.
The cumulative effect: an agent can safely co-curate your ontology with a complete forensic trail. That’s the new thing.

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Where to start

  • Want to see it work in 5 minutes? Run the tutorial. Forks the bundled pack, adds a researcher type, proves the wiring end-to-end.
  • Want the agent recipe? Read skills/schema-author/SKILL.md. 7-phase workflow agents follow when they detect a schema-evolution opportunity.
  • Want the rules of thumb? Read skills/conventions/schema-evolution.md. Decision tree for when to add a type vs alias vs prefix. <20 pages don’t pack-codify. 100+ pages need first-class types.
  • Want the architecture? The “Schema Cathedral v3 (v0.40.7.0)” section in CLAUDE.md has the 14-bullet module-by-module breakdown, each citing the design decision and codex finding that motivated it.
  • Want to set up an agent that co-curates your brain? Run modusbrain auth register-client my-agent --scopes admin to mint an OAuth client your remote agent can use to call schema_apply_mutations over MCP. The agent then runs detect → suggest → apply on its own cadence and asks you to approve substantive changes.
The killer feature isn’t “schemas.” Personal knowledge systems have had schemas forever. The killer feature is that your AGENT can shape them safely on your behalf, with structural integrity guarantees that match what you’d expect from a database, not a notes app. That’s what we built. Try it on a corpus you actually have and the numbers go up.