A series · One invented business
The vault and the graph
An Obsidian vault is a folder of Markdown notes. This series shows, from the simplest case to the hardest, how that folder becomes the memory of an agent graph, using one invented business whose vault grows a chapter at a time.
One invented business
Whitlock & Marsh Grounds is a two-person landscaping company in the invented town of Fenwick Ridge. Dana Whitlock visits, designs and plants; Eli Marsh runs the mowing crew, irrigation repair and hauling. They are not real, and neither is anything in their vault. I invented them so every chapter can show the same notes growing instead of a new toy example each time.
The idea
Obsidian describes a vault as a folder on your local file system where it stores your notes, and says it stores them as Markdown-formatted plain text files.
My viewMy argument is that this is exactly the shape an agent graph’s memory node needs: plain files that people already write, linked to each other, that an agent can read before it acts. The series tests that one chapter at a time, and says where it stops being true.
The chapters
3 open, 5 coming.
Reading the vault
C1 · Open
A vault is a folder
Plain Markdown files, wikilinks and backlinks: the whole vault of an invented landscaping firm, note by note.
C2 · Open
Read before you act
Rules, decisions and procedures as an agent’s memory: the same customer request answered with the vault and without it.
Builds on C1 A vault is a folder
Writing and structure
C3 · Open
Writing back
The agent adds to the vault: what it may write, where, and how a person sees the change before it counts.
Builds on C2 Read before you act
C4 · Coming
Structure an agent can rely on
Folders, naming and note properties that let an agent find the right note without guessing.
Builds on C3 Writing back
In the graph, and at scale
C5 · Coming
The vault inside an agent graph
The vault as the memory node in a graph of models, tools, routers, gates and people.
Builds on C2 Read before you act, C4 Structure an agent can rely on
C6 · Coming
Permissions and privacy
Which notes which agents may read or write, and what must never be in a vault an agent can reach.
Builds on C5 The vault inside an agent graph
C7 · Coming
History and review
Versioning the vault so every change an agent makes can be seen, compared and undone.
Builds on C3 Writing back
C8 · Coming
At scale
When the vault is too big to read whole: search, summaries and what to leave out.
Builds on C6 Permissions and privacy, C7 History and review
What this series is not
- A tour of Obsidian. It covers only what an agent needs from a vault, and every fact about the app cites its official help.
- A product pitch. No plugin, service or tool is recommended, and nothing here is for sale.
- A real business. Every name, town and note is invented, and no real client or vault is behind them.
- A model benchmark. The agent’s answers in the figures are scripted to show the shape of the idea; no model is called.
Sources
Obsidian Help Create a vault. Official help; read 2026-10-30.
What a vault is.
- The definition of a vault
Obsidian Help How Obsidian stores data. Official help; read 2026-10-30.
Notes as Markdown plain text files, and the configuration folder in the vault root.
- Notes stored as Markdown-formatted plain text files in a vault
Each fact about Obsidian or Claude Code is paraphrased from the page named, read on the date shown. Where a sentence is my own reading, it is marked “My view”. The business, its people and its notes are invented.