---
slug: core-concepts
title: "Core concepts: Event · Entity · Tag"
description: "Saving creates three things. Knowing who makes each one tells you what to care about: why entities keep search alive, and why tags are worth attaching."
lang: en
---


# Core concepts: Event · Entity · Tag

Saving something to AiAkiv creates three things. Knowing **who makes each one**
tells you what actually deserves attention.

| | What it is | Who makes it | How much it matters |
|--|------|-----------|------------------|
| **Event** | An account of something (one piece of what happened) | **The user's input** | ▽ It's simply what was saved |
| **Entity** | A key thing appearing in it | AI-extracted + the user's | ● Important: search lives here |
| **Tag** | An extra handle for finding it | AI-suggested + the user's | ● Important: the axis you slice by |

## Event: the account the user saved

One save is one Event. Save "we moved combat to turn-based" and that's an Event.
**The Event is the text the user wrote.** On save, AiAkiv attaches a **short
summary** and **Entities** to it automatically. Search hands you the summary;
when you need more, you pull the full text.

What matters is that an Event **doesn't sit alone.** Entities and Tags weave it
to the others. That weaving is the whole of AiAkiv.

## Entity: why it matters

**An Entity is a thing that appears in the event:** a person, a feature, a file,
a concept. In "we moved combat to turn-based", `combat system` and `turn-based`
are Entities. They're **extracted automatically** on save (NER).

Why it matters: **Entities are the knots that tie events together.**

- If five events share the Entity "combat system", those five form one thread.
  → "How did the combat system change?" is answered by that whole thread.
- If an inventory event and a save-file event share the Entity `serialization
  schema`, then "why did those two change together?" is answered through that
  shared knot.

**One rule to follow: one name per thing.** Always call the same thing by the
same name. Mixing "save format" and "savefile format" splits one Entity into two
and cuts the knot. Keep names consistent and the graph weaves itself.
(→ [Saving](saving))

## Tag: why it matters

**A Tag is a label the user attaches.** If an Entity is "who and what appeared",
a Tag is "what kind of event this is": `decision`, `bug`, `balance`, `retro`.

Why it matters: **it becomes the axis you slice by later.**

- "Show me just the decisions" / "just the bug history". You need Tags to cut
  that way.
- Attach both a kind (decision / bug…) and a topic (combat / save…) and you can
  narrow on the intersection.

**The AI suggests a few Tags on save**, and **the user can add to them or fix
them.** Whether the suggestions are left alone or tuned, that small bit of
involvement comes back as search quality.

## At a glance

- **Event** is the account the user saved. The AI adds the summary and Entities.
- **Entity** is the knot that ties events together (AI-extracted, plus the
  user's). Save with **one name per thing** and search comes alive.
- **Tag** is the axis. The AI suggests, the user tunes. It pays off when you
  slice later.

## Next

- How to save so these concepts pay off → [Saving](saving)
- Searching by knot and axis → [Searching](searching)