# `AshNeo4j.Type.Vector`
[🔗](https://github.com/diffo-dev/ash_neo4j/blob/v0.10.1/lib/type/vector.ex#L5)

Ash attribute type for vector embeddings, stored as a Neo4j `LIST<FLOAT>`.

The Elixir-side value is a plain `[float()]` list, and it is persisted as a
`LIST<FLOAT>` node property — which is what Neo4j's vector indexes and
`vector.similarity.cosine/2` operate on. The native Bolt 6.0 `%Bolty.Types.Vector{}`
type is a *query-parameter* wire type and **cannot be written as a node
property**, so it is never used for storage. `cast_input/2` and `cast_stored/2`
still accept a `%Bolty.Types.Vector{}` defensively and unwrap it to `[float()]`.

> #### Cypher 25 required {: .warning}
> Vector operations require Cypher 25 (Neo4j ≥ 2025.06) — not Bolt 6.0. With
> list storage and list query params, similarity search works over Bolt 5.8.
> This is an AshNeo4j-level requirement — see `AshNeo4j.Cypher.require_cypher25/0`.

## Constraints

  * `:element_type` — `:float32` (default) or `:float64`
  * `:dimensions` — expected number of dimensions; validated on cast when set

## Usage

    attribute :embedding, AshNeo4j.Type.Vector,
      constraints: [element_type: :float32, dimensions: 1536]

See `AshNeo4j.Vector` for index creation helpers and `AshNeo4j.Functions.VectorSimilarity`
for cosine similarity filtering/sorting.

# `handle_change?`

# `prepare_change?`

---

*Consult [api-reference.md](api-reference.md) for complete listing*