Personal knowledge base
A personal knowledge base you don't have to maintain
Built from conversations you already had, instead of notes you have to keep writing.
Sanctuary is a Mac app that reads your own Messages history and turns it into something you can search, ask and read — without a single note to file.
No card for the trial. Then $29 a month or $275 a year, cancel anytime · see pricing. For Mac. Everything stays on your computer.
Also:
- What was that restaurant Sarah sent me?
- Who recommended that doctor?
- Find the article someone sent me about AI.
The upkeep is what kills them
Every personal knowledge base starts the same way: a clean structure, a tagging scheme, good intentions. Then a busy month happens and it stops being true. The problem was never the tool — it is that keeping one requires you to write down what you already know, forever.
You already wrote it down
Years of it, in Messages. Where your friend told you to eat. Who to email about the job. The apartment listing, the podcast, the birthday plan, the thing you promised to send back. It is not organized, but it is all there, and it is genuinely yours.
Sanctuary turns that into a base you can ask
It reads the Messages history on your Mac and builds a library out of it — links, the people who sent them, the conversations around them, and the loose ends you never closed. Ask it in plain language: no query syntax, no tags to have applied in advance.
Organized around people, not folders
The useful unit of memory is rarely a folder. It is a person: what they like, what they recommended, what you owe each other, what is coming up for them. Sanctuary groups what it finds that way, and by project or topic when that fits better.
Every fact shows its evidence
A knowledge base you cannot audit is just confident guessing. Each thing Sanctuary claims — a job change, a preference, a promise — links back to the message it came from, and you can mark it wrong. Raw facts and anything inferred stay in separate places.
Living pages instead of stale notes
Ask for a list — people you should reconnect with, everything about a trip, what is open on a project — and save it as a page. Re-open it later and it refreshes itself against your library, flagging what changed rather than going quietly out of date.
It can feed your AI tools too
Connect Claude and it can consult your base through a permission switch you control, so answers are grounded in your own history. What it may see is metadata by default; the message text is a separate switch you have to turn on.
Private by construction
Your messages are read on your own machine and never uploaded. There is no account, no server copy, and no telemetry in the app. Turn your wifi off and it still answers.
How the base builds itself
- Step 1
Point it at what you already have
Messages and Contacts on your Mac, with Apple Mail, browser history and exports optional and off by default.
- Step 2
It builds the index locally
Links, people, places, dates and open loops are extracted on-device into a local database — no upload, no account.
- Step 3
Structure appears on its own
Titles, summaries and topics fill in; person cards assemble from the messages themselves, each claim carrying its source.
- Step 4
Ask, browse, or save a page
Query it in plain language, browse by person or topic, and keep the answers you rely on as pages that refresh themselves.
Sanctuary vs a note-based knowledge base
| Sanctuary | Notion, Obsidian, Evernote | |
|---|---|---|
| Getting knowledge in | Read from conversations you already had | You write and file every note |
| Day-one contents | Years of history | A blank vault |
| Structure | People, topics and projects, derived | Folders, tags and links you design |
| Goes stale when you get busy | No | Yes |
| Search | Plain-language questions with sources | Keyword and query syntax |
| Where it lives | Your Mac, no account | Local file or vendor cloud |
| Best at | Recalling what happened and who said it | Composing and linking your own writing |
Comparison reflects how these tools are designed to be used, not a feature-by-feature audit.
Who it's for
- People who have started a second brain three times and abandoned it three times
- Anyone who remembers a recommendation exists but not who gave it
- Freelancers and founders tracking commitments across dozens of threads
- Privacy-minded users who want recall without handing a vendor their history
Common questions
What is a personal knowledge base?
A private store of the things you want to remember — people, ideas, references, commitments — that you can search later. Notion, Obsidian, Evernote and Apple Notes are the usual homes for one.
How is this different from Obsidian or Notion?
Those are excellent places to write. Sanctuary is not a writing tool: it assembles the base from conversations you already had, so there is nothing to type in. Many people keep both — notes for thinking, Sanctuary for recall.
Do I have to tag or organize anything?
No. Topics, person cards and projects form on their own. You can create projects and correct anything that is wrong, but the base is useful before you touch it.
Is it a second brain?
It is the recall half of one. The capture step — the part that usually collapses — is already done, because your messages are the capture.
Can I trust what it says?
Every claim shows the message it came from, and you can mark it wrong. Nothing is asserted without evidence you can click through to.
Does anything leave my Mac?
Not by default. Optional cloud AI runs on a key you provide and sends only a link, its site and a short excerpt. Everything else stays local.