# Zettelkasten Linking Reference

## Three Structural Layers

1. **Content notes** — individual intents (`~/.plastic/store/ID--slug/ID--slug.md`)
2. **Structure notes** — INDEX.md clusters that organize related intents
3. **Main structure note** — INDEX.md itself, the top-level entry point

## Three Connection Types (Ranked)

1. **Direct links** (strongest): wikilinks in the `## Links` section, the projection of the
   frontmatter graph. Each entry is `- [[id--slug|<target's full intent: text>]]` (cross-store:
   `- [[store:id--slug|...]]`), a clickable `id--slug` target labeled with the target's full
   `intent:` text. Ordering is mandatory: all `sources` first (top), then all `chain`,
   frontmatter order preserved within each group. Sources never appear at the end. No
   source/chain tags, no sub-grouping.
2. **Sources/Chain** (knowledge graph): `sources` = direct ascendants this was created from (formation, acyclic, must-load); `chain` = forward continuations and related successors (may cycle, lighter context). See [`how-plastic-sources-and-chains-intents.md`](https://github.com/zalom/plastic/blob/main/docs/concepts/how-plastic-sources-and-chains-intents.md) for the full model.
3. **Tags** (weakest) — shared tags, `project-<name>` for project membership

## When to Create a Cluster

A cluster is a structure note heading. Create one when:
- 3+ intents share a topic but aren't grouped
- You notice a pattern across intents
- A topic area is growing and needs an entry point

## Principles

- Links are the primary organizational mechanism, not folders
- Structure is a lens, not a container — intents remain first-class citizens
- Clusters are manually curated, not auto-generated
- Facts are invalidated, never deleted — completed intents stay in INDEX.md