A graph is memory with connections.
A useful operating graph keeps five things together: what exists, how things relate, where the claim came from, when it was true, and how confident the system should be.
QUESTION
What should the brain be able to answer?
ENTITIES
Person · Project · Decision · Task · Source · Event
RELATIONSHIPS
supports · contradicts · supersedes · part_of · prerequisite
EVIDENCE
Source path, author, timestamp, excerpt, confidence
OPERATING LOOP
Recall → act → feedback → consolidate → maintain → evaluate
STOP CONDITION
If the source, relationship, or confidence is unclear, flag it for review.Start with the questions your brain needs to answer. Then define the smallest set of entities and relationships that makes those answers possible.
Entity
A person, project, decision, task, source, or event.
Relationship
A typed connection with a clear meaning.
Evidence
The source that supports the claim.
Time
When the claim was true and when it was recorded.
Confidence
How certain the system is about the connection.
Owner
Who can review or change the information.
create table graph_entities (
id text primary key,
type text not null,
name text not null,
source_ref text,
observed_at timestamptz,
confidence numeric check (confidence between 0 and 1)
);
create table graph_edges (
from_id text references graph_entities(id),
relation text not null,
to_id text references graph_entities(id),
evidence_ref text,
observed_at timestamptz,
confidence numeric check (confidence between 0 and 1)
);This is a deliberately small starting shape, not a drop-in production schema. Add constraints, ownership, and audit history only when a real workflow needs them.
The graph is the connective tissue.
Second Brain 2.1 is designed around an operating brain with evidence-gated learning, task truth, cadence, memory maintenance, provider routing, and automation packaging. This guide explains the architecture behind those pieces. It does not ask you to build every piece at once.
See Second BrainYour first build
- 01Pick one real question that needs connected context.
- 02Create five entity types and three relationship types.
- 03Attach a source and timestamp to every first link.
- 04Run one daily recall workflow.
- 05Capture one correction or confirmation.
- 06Review what changed before adding more automation.