Note types and frontmatter

Every note is a .md file with a YAML frontmatter block at the top. The type field says what the note is and, therefore, which folder it lives in.

The 12 types

type	Folder	What for
source	wiki/sources/	Summary of a source (a meeting, an article), pointing to the original in raw/
concept	wiki/concepts/	An idea or technique: idempotency, message queue
entity	wiki/entities/	A concrete thing: person, project, company, tool
decision	wiki/decisions/	A decision and the why, with the date it took effect
synthesis	wiki/syntheses/	A text that combines several notes into an overview
rule	memory/rules/	A rule every agent follows. An agent only creates it with your explicit request.
preference	memory/preferences/	How you like things to be done
gotcha	memory/gotchas/	A gotcha: what went wrong and how to avoid it
procedure	memory/procedures/	A repeated step-by-step
fact	memory/facts/	An atomic fact (subject, predicate, object) with a validity period
episode	memory/episodes/AAAA/MM/	The record of something that happened on a date
handoff	memory/handoffs/	The end of a session: what was done, what is left, where it stopped

A wiki note

A decision from the example brain, with typed relations and an earlier version that it supersedes:

---
id: 01KNWQPCCGW9YN4PHGN519T4H6
type: decision
title: Usar SQS para filas
scope: project:atlas
tags: [infra, filas]
sources: ["[[raw/meetings/2026-05-03-arquitetura]]"]
trust: high
origin: agent:claude-code
created: 2026-05-03
updated: 2026-11-10
confirmed: 2026-11-10
valid_from: 2026-05-03
valid_until:
supersedes: ["[[usar-rabbitmq-para-filas]]"]
superseded_by: []
expires_at:
uses: ["[[SQS]]"]
decided_by: ["[[Ana Prado]]", "[[Bruno Tavares]]"]
part_of: ["[[Projeto Atlas]]"]
depends_on: ["[[Idempotência]]"]
---
# Usar SQS para filas

O [[Projeto Atlas]] migrou do [[RabbitMQ]] para o [[SQS]] por custo de operação.

A fact

Facts do not need a title: Cabeção shows sujeito predicado objeto (subject, predicate, object).

---
id: 01KWE9TKFRS0SE22ZDN9SJEEPP
type: fact
subject: "[[Projeto Atlas]]"
predicate: led_by
object: "[[Bruno Tavares]]"
valid_from: 2026-09-01
valid_until:
supersedes: ["[[fato-ana-lidera-atlas]]"]
superseded_by: []
trust: high
origin: human
created: 2026-09-01
updated: 2026-09-01
---
Bruno Tavares lidera o Projeto Atlas desde setembro de 2026.

Fields Cabeção takes care of

When the write goes through Cabeção (an agent over MCP or through the CLI), id, created, updated, origin, edited_by, approved_by and approved_at are filled in by it; the agent does not choose these values. The id is a ULID: 26 uppercase characters that do not change if the note is renamed.

In a note you write by hand (in Obsidian, for example), the most important field is type: it tells Cabeção what the note is. Without an id, the note is still indexed and searchable, identified by its path; status counts it among the notes "without an id". A note with neither id nor type is treated as a loose note, outside the schema, and also shows up in search.

Fields that Cabeção does not know are preserved. You can have your own Obsidian properties.

Scope

scope separates what applies everywhere from what applies to one project:

• global: always applies (the default for notes saved by agents);
• project:<nome>: applies to one project, like project:atlas.

A search or a recall with project:atlas brings the project's notes and the global ones.

The list of all fields, with the format of each one, is in the frontmatter reference.