> ## Documentation Index > Fetch the complete documentation index at: https://docs.custral.com/llms.txt > Use this file to discover all available pages before exploring further. # Set up auto-fill on a property > Create an AI auto-fill agent on a property. One auto-fill is allowed per property. **Requires scope:** `property_agents:write`. ## OpenAPI ````yaml /openapi-v1.json post /v1/property-agents openapi: 3.1.0 info: title: Custral API version: v1 description: >- The curated, versioned, API-key-authenticated public REST surface (`/v1`). Every endpoint here is what the official SDKs (`@custral/sdk`) and the MCP server are built on. Authenticate with a secret API key (`sk_…`) created in **Settings → Applications**. contact: name: Custral Support email: hello@custral.com url: https://custral.com license: name: Proprietary url: https://custral.com servers: - url: https://api.custral.com description: Production security: - ApiKey: [] tags: - name: Identity description: Introspect the calling API key. - name: Records description: Create, list, retrieve, and update records on any object. - name: Objects description: Read the object (table) schema of your workspace. - name: Conversations description: View, manage, and ingest conversations and their messages. - name: MCP description: Introspect the Model Context Protocol tool surface for a key. - name: Documents description: Read record notes / page documents as markdown. paths: /v1/property-agents: post: tags: - Property agents summary: Set up auto-fill on a property description: >- Create an AI auto-fill agent on a property. One auto-fill is allowed per property. **Requires scope:** `property_agents:write`. operationId: createPropertyAgent requestBody: required: true content: application/json: schema: $ref: '#/components/schemas/CreatePropertyAgentBody' responses: '200': description: The created auto-fill agent. content: application/json: schema: type: object properties: data: $ref: '#/components/schemas/PropertyAgent' reqId: $ref: '#/components/schemas/RequestId' '401': $ref: '#/components/responses/Unauthorized' '403': $ref: '#/components/responses/Forbidden' components: schemas: CreatePropertyAgentBody: type: object description: >- Set up AI auto-fill on a property. One auto-fill is allowed per property. properties: objectId: type: string description: The object (`obj_…`) the property belongs to. example: obj_123 propertyId: type: string description: The property (`prop_…`) to auto-fill. example: prop_123 kind: type: string enum: - summarize - research - classify - prompt example: research instructions: type: string description: What the AI should output for the property. model: type: string description: Model id, or `auto` (default). sources: $ref: '#/components/schemas/PropertyAgentSourcesInput' triggerTypes: type: array items: type: string enum: - onCreate - onUpdate - recurring description: Automatic triggers; omit for manual-only. onlyIfEmpty: type: boolean description: Only write when the property is empty. Defaults to false. isEnabled: type: boolean description: Whether the auto-fill is enabled. Defaults to true. required: - objectId - propertyId - kind - instructions PropertyAgent: type: object description: >- An AI auto-fill agent — the config attached to a single property that fills its value with AI. properties: id: type: string example: pagent_123 objectId: type: - string - 'null' example: obj_123 propertyId: type: - string - 'null' example: prop_123 kind: type: - string - 'null' enum: - summarize - research - classify - prompt - null example: research instructions: type: - string - 'null' example: Using the record's Website, output the company's industry. model: type: - string - 'null' example: auto sources: type: object description: Context toggles the agent reads from. additionalProperties: true triggerTypes: type: array items: type: string enum: - onCreate - onUpdate - recurring recurringCron: type: - string - 'null' scopeFilterJson: description: >- An optional record filter restricting which records the agent fires on, or null. dependsOn: type: array items: type: string description: propertyIds that must run before this agent. requiresProperties: type: array items: type: string description: propertyIds that must be non-empty before this agent runs. onlyIfEmpty: type: boolean isEnabled: type: boolean createdAt: type: - string - 'null' format: date-time updatedAt: type: - string - 'null' format: date-time required: - id RequestId: type: string description: >- A per-request id (`req_…`). Quote it to support when reporting a problem. example: req_2a1f9c8e7b6d5 PropertyAgentSourcesInput: type: object description: >- Context toggles. Omitted toggles default sensibly for the kind (research enables the web). properties: recordContext: type: boolean description: Include the record's own fields in the prompt. web: type: boolean description: Allow web research. Error: type: object description: >- The failure envelope. Every error carries a machine-readable `code` and the `reqId` of the failing request. properties: error: type: object properties: code: type: string example: insufficient_scope required: - code reqId: $ref: '#/components/schemas/RequestId' required: - error responses: Unauthorized: description: >- The API key is missing, unknown, inactive, or expired (`code: invalid_api_key`). content: application/json: schema: $ref: '#/components/schemas/Error' example: error: code: invalid_api_key reqId: req_2a1f9c8e7b6d5 Forbidden: description: >- The key lacks the scope this endpoint requires (`code: insufficient_scope`). content: application/json: schema: $ref: '#/components/schemas/Error' example: error: code: insufficient_scope reqId: req_2a1f9c8e7b6d5 securitySchemes: ApiKey: type: http scheme: bearer bearerFormat: sk_... description: >- A Custral **secret** API key (`sk_…`), created in Settings → Applications. Sent as `Authorization: Bearer sk_…`. The `X-Api-Key: sk_…` header is also accepted and takes precedence. Never expose a secret key in a browser. ```` ## Related topics - [Property Auto-Fill Agents](/ai/property-agents/overview.md) - [The Property Agent object](/dev/api-reference/property-agents.md) - [Triggers](/ai/property-agents/triggers.md) - [Troubleshooting](/ai/property-agents/troubleshooting.md) - [Delete an auto-fill agent](/api-reference/property-agents/delete-an-auto-fill-agent.md)