> For clean Markdown of any page, append .md to the page URL.
> For a complete documentation index, see https://docs-beta.getzep.com/v4/sdk-reference/graph/get-ontology/llms.txt.
> For AI client integration (Claude Code, Cursor, etc.), connect to the MCP server at https://docs-beta.getzep.com/_mcp/server.

# Get graph ontology

GET https://api.getzep.com/api/v4/graphs/{graph_uuid}/ontology

Reference: https://docs-beta.getzep.com/sdk-reference/graph/get-ontology

## Authentication

- `Authorization` header (required) (prefixed with ` Api-Key  `) — Type "Api-Key" followed by a space and the project API key.

## Request

### Path parameters

- `graph_uuid` (string, required) — Graph UUID

## Response

### 200

OK

- `edge_types` (list of v4.EdgeType, optional) — The edge types defined in the ontology in effect at this scope.
- `entity_type_hierarchy` (V4OntologyEntityTypeHierarchy, optional) — The entity type hierarchy (spec ontology-1). Omitted when the ontology is flat.
- `entity_types` (list of v4.EntityType, optional) — The entity types defined in the ontology in effect at this scope.
- `inherited` (boolean, optional) — Whether this is the project's default value rather than an override set on this graph.

## Errors

### 400 Bad Request Error

Bad Request

- `error` (v4.ErrorBody, optional)

### 401 Unauthorized Error

Unauthorized

- `error` (v4.ErrorBody, optional)

### 404 Not Found Error

Not Found

- `error` (v4.ErrorBody, optional)

## Types

### v4.EdgeType

- `description` (string, optional) — A description of the relationship this edge type represents, used to guide extraction.
- `name` (string, optional) — The name of the edge type, in upper snake case.
- `properties` (list of v4.EntityProperty, optional) — The custom properties defined on edges of this type.
- `source_targets` (list of v4.EdgeSourceTarget, optional) — The allowed source and target entity type pairs for edges of this type.

### V4OntologyEntityTypeHierarchy

The entity type hierarchy (spec ontology-1). Omitted when the ontology is flat.

### v4.EntityType

- `description` (string, optional) — A description of the entity type, used to guide extraction.
- `identity_properties` (list of string, optional) — The property names that determine whether two nodes of this type are the same entity.
- `name` (string, optional) — The name of the entity type.
- `properties` (list of v4.EntityProperty, optional) — The custom properties defined on nodes of this type.

### v4.ErrorBody

- `code` (string, optional)
- `details` (map from string to any, optional)
- `message` (string, optional)
- `param` (string, optional)
- `request_id` (string, optional)

### v4.EntityProperty

- `description` (string, optional) — A description of the property, used to guide extraction.
- `name` (string, optional) — The name of the property.
- `type` (enum, optional) — The value type of the property: text, int, float, or boolean.
  - Allowed values: `text`, `int`, `float`, `boolean`

### v4.EdgeSourceTarget

- `source` (string, optional) — The entity type an edge of this type originates from.
- `target` (string, optional) — The entity type an edge of this type points to.

## Examples

**Response**

```json
{
  "edge_types": [
    {
      "description": "string",
      "name": "string",
      "properties": [
        {
          "description": "string",
          "name": "string",
          "type": "text"
        }
      ],
      "source_targets": [
        {
          "source": "string",
          "target": "string"
        }
      ]
    }
  ],
  "entity_type_hierarchy": {},
  "entity_types": [
    {
      "description": "string",
      "identity_properties": [
        "string"
      ],
      "name": "string",
      "properties": [
        {
          "description": "string",
          "name": "string",
          "type": "text"
        }
      ]
    }
  ],
  "inherited": true
}
```