Graph, relations and facts over time

The notes in the brain form a graph. Cabeção builds this graph in the local database on every scan, from the text of the notes: there is nothing to maintain by hand besides the links themselves.

Where links come from

Link	How you write it	Example
Wikilink	[[Nota]] in the body, as in Obsidian (also [[Nota|apelido]], [[Nota#Seção]] and [[pasta/Nota]])	O [[Projeto Atlas]] usa [[SQS]].
Typed relation	A frontmatter property with a list of wikilinks	uses: ["[[SQS]]"]
Supersession	supersedes and superseded_by	supersedes: ["[[usar-rabbitmq-para-filas]]"]
Fact	subject and object of a type: fact note	subject: "[[Projeto Atlas]]"
Unlinked mention	Nothing: Cabeção finds the title (or an aliases entry) of another note mentioned in the text	"the meeting about Projeto Atlas"

Unlinked mentions show up in graph, but they do not boost search results. Names that are too short (fewer than 3 letters), too generic ("Project", "Ideas") or shared by more than one note do not become mentions.

Typed relations

Six relations come built in:

Relation	Meaning
uses	uses
part_of	is part of
depends_on	depends on
decided_by	was decided by
works_on	works on
related_to	is related to

Each one is a frontmatter property with a list of wikilinks, which Obsidian shows as a list property:

uses: ["[[SQS]]"]
decided_by: ["[[Ana Prado]]", "[[Bruno Tavares]]"]
part_of: ["[[Projeto Atlas]]"]

To have others, add the names to relations in .cabecao.json, like "relations": ["mentored_by"]. An agent adds a relation with the relate tool.

Facts

A fact is a small note with three parts: subject, predicate and object. The predicate is a lowercase identifier, like uses_queue or led_by. The object can be another note or a plain value.

type: fact
subject: "[[Projeto Atlas]]"
predicate: led_by
object: "[[Bruno Tavares]]"
valid_from: 2026-09-01
supersedes: ["[[fato-ana-lidera-atlas]]"]

Facts store what changes over time (who leads, what is used, where something runs) without erasing what was true before.

Time validity

Any note can say when it applies:

Field	Meaning
valid_from	Becomes valid on this date (inclusive)
valid_until	Stops being valid on this date (exclusive): what is valid "until May 3" and what is valid "from May 3" do not overlap
expires_at	Expires on this date, like a handoff that only matters for a month
supersedes / superseded_by	Another note has replaced this one

On any given date, each note is in one of three states:

• current (current);
• expired (expired): past valid_until or expires_at, or superseded;
• not yet valid (not_yet_valid): valid_from is after the date.

You do not need to fill in valid_until on the old note when you write the new one: the supersedes link is enough. Cabeção derives the supersession date from the new note's valid_from (or created).

Expired notes never disappear from search: they move down the list and show up marked. To ask about the past, pass the date (--as-of in the CLI, as_of over MCP):

$ cabecao facts --subject "Projeto Atlas" --predicate led_by --as-of 2026-03-01
2 fato(s), validade em 2026-03-01:

1. Projeto Atlas · led_by · Ana Prado  vigente
   de 2026-01-12 até 2026-09-01   memory/facts/fato-ana-lidera-atlas.md
   substituído por: memory/facts/fato-bruno-lidera-atlas.md

2. Projeto Atlas · led_by · Bruno Tavares  AINDA NÃO VIGENTE
   de 2026-09-01 até em aberto   memory/facts/fato-bruno-lidera-atlas.md
   substitui: memory/facts/fato-ana-lidera-atlas.md

More examples, with search and the graph, in Search.

Agents cannot supersede rules

A rule of yours (type: rule in memory/rules/) can only be superseded by another rule of yours. If an agent's note says supersedes: ["[[sua-regra]]"], the rule stays current and stays in recall.