No terminal needed
Claude can write straight into your vault: a plan, a summary, a draft, anything it has just produced. You add one address, approve it once, and from then on "save that in Sumibako" is a thing you can say. There is nothing to install and no token to copy.
Before you start
Custom connectors work on Free, Pro, Max, Team and Enterprise. On Free you can have one at a time.
Claude owns these menus and can rename them. Checked against Claude's own guide to custom connectors on 2026-09-21. If a label has moved since, the address is still the only thing you need.
CustomizeConnectors
In Claude, go to Customize and then Connectors. The link below goes straight there.
Open Claude connectorsOn Team and Enterprise an Owner has to add it for the organisation first, under Organization settings then Connectors, then Add, then Custom, then Web. After that everyone else sees it here and only presses Connect.
+Add custom connector
Press the plus, choose Add custom connector, and paste the address into the URL field. Leave Advanced settings alone - there is no client ID or secret to enter, and the sign-in happens in the next step.
https://sumibako.com/api/mcpConnect
Claude sends you here to sign in, then shows you exactly what it will be allowed to do: read and search every page in your vault, write new ones, and publish a page it wrote so it can hand you a link. If you do not have a Sumibako account yet, you make one at this moment. It is free.
The tools arrive on their own; there is nothing to switch on in the chat. Say what you want and it picks the right one.
Paste this into Claude. It asks for a real page rather than a list of tools, because an assistant will cheerfully describe a connector it has not loaded, and only a page that actually appears settles it.
Save a page in Sumibako called "Hello" that says this connector works, then tell me what its icon is.It files the page and tells you the emoji it chose for it. Open Sumibako and the page is in your sidebar, icon and all. If it instead explains how you could do that yourself, it is not connected - go back to step one.
Eight things worth knowing you can ask for. Each one says the word Sumibako inside the sentence, which is the part people leave out: without it, Claude has no way to tell that “save this” means your vault rather than its own memory of the conversation.
You want to keep what it just wrote
Save that in Sumibako as a page called "Q4 hiring plan".The page appears in your vault, with an emoji it picks itself. Headings, lists, tables and code all survive the trip.
You want to send it to somebody
Publish that page and give me the link.A sumibako.com address that opens for anyone, with no account and no sign-in. It carries noindex, so it is shareable without being findable.
You want the same page updated, not a second one
Update my "Weekly review" page in Sumibako rather than making a new one.It writes over the page it filed before. This is the difference between a vault and a pile, and it is worth saying out loud the first few times.
You want to add to something without retyping it
Add these three bullets to the end of my "Reading list" page in Sumibako.Only the new lines are sent. The rest of the page is never re-uploaded, so nothing already there can be lost on the way.
You want one line changed
In my "Launch checklist" in Sumibako, change "Tuesday" to "Thursday".One exact replacement. If that text appears twice it refuses rather than guessing which one you meant.
You cannot remember where you put something
Search Sumibako for what I wrote about pricing.The matching pages, by their words. Ask for nothing in particular and it lists the newest.
You want it to read something you wrote by hand
Read my "Onboarding notes" page from Sumibako and tell me what is missing.The page comes back as Markdown, which is the form it can then edit and send back. It works on pages you typed yourself, not only ones it filed.
You want to know what you are using
What plan am I on in Sumibako, and how much of it have I used?Your plan, your limits, what you have used, and what this particular connection is allowed to do.
The four that matter, because you are about to let a program write into your notes.
It cannot delete anything
There is no delete in the API at all, so nothing it does can destroy your writing. Unpublishing takes a link off the web and leaves the page where it is.
It cannot put your notes in front of strangers
A published page carries noindex. Making one findable by a search engine is a switch you flick yourself, per page, inside the app. It can hand you a link; it cannot get you into Google.
It cannot publish a page you wrote
A connector you signed in to may only publish pages it created itself. Your own pages are not its to put on the web.
It cannot reach anyone else's vault
The connection is scoped to the account that approved it and nothing else. Revoke it in the client's settings and it stops on its next request.
There is no "Add custom connector" button
You are on Team or Enterprise, where an Owner adds connectors for the whole organisation. Send them step one; you will then see it here with a Connect button.
It says you already have a connector
The free plan allows one custom connector at a time. Remove the other one, or upgrade Claude.
It connected, but it never writes anything
Say the word Sumibako in the sentence. Without it, Claude has no way to know that "save this" means your vault rather than its own memory of the conversation.
You want it to stop
Remove it under Customize, then Connectors, using Remove or the three-dot menu. It stops on its next request. Nothing it already wrote is affected - those are your pages now.
The longer version
Connect Claude.ai to your notes
The same setup with the reasoning left in: what the approval screen is actually granting, and why twenty versions of every page it overwrites are kept for a fortnight.
Also use ChatGPT?
Connect Sumibako to ChatGPT
The same vault, connected the same way. Both at once is fine.
Have a terminal?
Connect a coding agent
Claude Code, Cursor and Codex read the file off disk instead of sending it through the model, and need no plan at all.