> ## Documentation Index > Fetch the complete documentation index at: https://docs.vocobase.com/llms.txt > Use this file to discover all available pages before exploring further. # Get a custom function ## OpenAPI ````yaml /openapi.json get /functions/{id} openapi: 3.1.0 info: title: Vocobase API version: '2.0' description: >- API for managing voice AI agents, documents, and calls on the Vocobase platform. servers: - url: https://api.vocobase.com/api/v2 description: Production security: - bearerAuth: [] tags: - name: Config description: >- Read and update account configuration, webhook settings, and telephony credentials. - name: Agents description: Create, read, update, and delete voice AI agents. - name: Voices description: >- List voice tiers, available voices, and stream preview audio for agent configuration. - name: Documents description: Upload, manage, and delete knowledge base documents. - name: Agent Documents description: Link and unlink documents to agents for knowledge base integration. - name: Calls description: Initiate outbound calls and view call history. - name: Phone Numbers description: >- Import DIDs, assign agents for inbound routing, and re-sync carrier Application bindings. - name: Inbound Routing Policies description: >- Define pre-answer routing decisions for inbound calls before AI sessions are created. - name: Telephony Connections description: Create, list, rename, and disconnect named V2 telephony connections. - name: VoiceLink Management description: Manage VoiceLink reseller clients, DID mapping, and readiness sync. - name: Projects description: Organize agents into projects. Every agent belongs to exactly one project. - name: Dictionaries description: Speech-recognition dictionary CRUD and agent attachment. - name: Sessions description: Browser-initiated WebRTC voice sessions for in-app voice agents. - name: Campaigns description: Batch outbound calling. - name: Billing description: Balance, transactions, and usage summaries. - name: Custom Functions description: HTTP endpoints the agent can call mid-conversation. - name: Extraction Sets description: Reusable sets of post-call extraction fields. - name: Lifecycle Hooks description: Automatic pre-call and post-call integration steps. - name: Messaging description: Bring-your-own WhatsApp sending. - name: Integration Logs description: Audit trail for integration calls. - name: Connectors description: Catalog of tools an agent can be connected to. - name: Customers description: B2B2B sub-tenants and their tool connections. - name: Agent Tools description: Binding connectors and connections to an agent. paths: /functions/{id}: get: tags: - Custom Functions summary: Get a custom function operationId: getFunction parameters: - name: id in: path required: true schema: type: string format: uuid description: Function ID. responses: '200': description: Success. content: application/json: schema: type: object properties: success: type: boolean const: true data: $ref: '#/components/schemas/CustomFunction' example: success: true data: id: fn_3d2c1b0a-9876-5432-10fe-dcba98765432 name: check_order_status description: Look up the status of a customer order by order number. method: POST url: https://api.example.com/vocobase/order-status header_keys: - X-Api-Key input_schema: - name: order_number type: string description: The customer's order number. required: true output_schema: - name: status type: string description: Current order status. required: true - name: eta_days type: number description: Days until delivery. required: false timeout: 10 started_messages: - Let me look that up for you. error_message: I could not reach the order system just now. created_at: '2026-07-02T10:15:00.000Z' updated_at: '2026-08-11T09:00:00.000Z' '401': $ref: '#/components/responses/Unauthorized' '404': $ref: '#/components/responses/NotFound' '429': $ref: '#/components/responses/RateLimitExceeded' '500': $ref: '#/components/responses/InternalError' components: schemas: CustomFunction: type: object properties: id: type: string format: uuid name: type: string description: snake_case. Must start with a letter. Maximum 50 characters. description: type: string description: >- 1–500 characters. The model reads this to decide when to call the function. method: type: string enum: - POST description: Always `POST`. url: type: string format: uri description: >- HTTPS endpoint. Maximum 2000 characters. `localhost` and private IPs are blocked in production. header_keys: type: array items: type: string description: >- Names of the custom headers you configured. Values are encrypted at rest and never returned. input_schema: type: array items: $ref: '#/components/schemas/SchemaField' description: Up to 100 fields. output_schema: type: array items: $ref: '#/components/schemas/SchemaField' description: Up to 100 fields. timeout: type: integer minimum: 1 maximum: 60 description: Seconds to wait for your endpoint. started_messages: type: array maxItems: 5 items: type: string maxLength: 200 description: Filler lines the agent may say while the call is in flight. error_message: type: string nullable: true maxLength: 500 description: What the agent says when your endpoint fails or times out. created_at: type: string format: date-time updated_at: type: string format: date-time SchemaField: type: object required: - name - type - description - required properties: name: type: string type: type: string enum: - string - number - boolean - string[] - number[] - custom description: type: string description: Shown to the model — this is how it decides what to pass. required: type: boolean jsonSchema: type: object additionalProperties: true description: Required when `type` is `custom`. A raw JSON Schema for the field. ErrorResponse: type: object properties: success: type: boolean const: false error: type: object properties: code: type: string message: type: string required: - code - message required: - success - error responses: Unauthorized: description: Missing or invalid API key. content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' example: success: false error: code: UNAUTHORIZED message: Invalid or missing API key NotFound: description: Resource not found. content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' example: success: false error: code: NOT_FOUND message: Resource not found RateLimitExceeded: description: Per-account rate limit exceeded. Retry after a short backoff. content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' example: success: false error: code: RATE_LIMITED message: Rate limit exceeded. Retry after 60 seconds. InternalError: description: Unexpected server error. content: application/json: schema: $ref: '#/components/schemas/ErrorResponse' example: success: false error: code: INTERNAL_ERROR message: An unexpected error occurred securitySchemes: bearerAuth: type: http scheme: bearer description: >- API key in format: `rg_live_xxxx`. Pass as a Bearer token in the Authorization header. ````