Vault

A folder of linked markdown that 9p navigates instead of re-reading your codebase.

A vault is a folder of markdown notes linked with [[wiki links]]. 9p reads the index, follows links to what’s relevant, and writes back what it learns. It’s an Obsidian vault if you point Obsidian at it, but Obsidian is optional. The structure is what matters, not the app.

Setup

9p init          # choose "vault"

Creates the scaffold and records the path in .9p/config.json:

vault/
  INDEX.md        master map. Everything reachable from here
  jobs/           reusable procedures the agent follows step by step
  decisions/      what was decided and why
  daily/          one note per working day
  projects/       one folder per project, master note named after the folder
  graph/          generated codebase maps (9p map)

Mapping the codebase

9p map

Explores the project and writes concise wiki notes into graph/: an index plus one note per module, each linking to related notes. Re-run it to refresh; it updates notes in place rather than duplicating.

This routes on economy bias deliberately: it’s bulk read-and-summarise across a whole repo.

The index-note pattern

The pattern that makes this work: every folder has a master note named after the folder, wiki-linked to everything inside it.

vault/jobs/release/release.md

# Release

1. Confirm CI is green on `main`
2. Follow [[changelog]] to write release notes
3. Run the steps in [[deploy-steps]]
4. Announce per [[announce-template]]

9p reads one note, follows the links, and arrives fully briefed. You don’t have to tell it which files to read.

Decisions

The highest-value notes are the ones git can’t reconstruct, why something is the way it is:

vault/decisions/why-no-orm.md

# Why we don't use an ORM

Decided 2026-03-14. Query shapes are join-heavy and we kept fighting the query
planner. Rejected: Prisma (migration story), Drizzle (fine, but the win didn't
justify the rewrite). Affects [[db-layer]], [[repository-pattern]].

Months later, “why was this decided?” has an answer.

Daily notes

Ask 9p to log at the end of a session:

9p ❯ write today's daily note: what we finished, what's next, what's blocked

Put a short index at the top of each daily note. Future sessions scan indexes instead of reading every note in full.

Anti-bloat

Worth stating in your 9P.md:

Vault rules:
- Append to an existing note; only create a new note when genuinely necessary
- Every new note must be linked from its folder's master note

Without a rule like that you accumulate hundreds of near-duplicate notes, and a sprawling vault is worse than none, the agent trusts stale notes over the code.

Point Obsidian at the folder if you want the graph view. It’s a good way for you to see the shape of the knowledge; 9p reads the markdown either way.