> ## Documentation Index > Fetch the complete documentation index at: https://docs.eclatira.com/llms.txt > Use this file to discover all available pages before exploring further. # Create a call > Initiate an outbound phone call using an agent. The agent's prompt and first_message support {{variable}} placeholders. Pass `variables` to fill them dynamically per call. Optionally override `first_message` entirely. Provide a `webhook_url` to receive a POST when the call completes. Set `provider` to "twilio" or "telnyx" to pick which provider places the call when the agent has both configured. When omitted, Twilio is used if configured, otherwise Telnyx. Pass an `Idempotency-Key` header to safely retry this request: a repeat with the same key and body replays the original response instead of placing a second call; the same key with a different body is rejected. ## OpenAPI ````yaml /openapi.json post /api/v1/calls openapi: 3.1.0 info: title: Eclatira API description: >- Programmatically create calls and batches, manage agents/tools/knowledge, and retrieve conversation analytics. contact: name: Eclatira Support email: contact@eclatira.com version: 1.0.0 servers: - url: https://app.eclatira.com description: API Server security: [] tags: - name: developer-api description: >- The API-key-authenticated developer surface: calls, batches, and agents. Authenticate with `Authorization: Bearer ek_...`. - name: Calls description: Place outbound calls with an agent, check status, list history. - name: Batches description: 'Outbound call campaigns: create, list, inspect, cancel, retry.' - name: Agents description: Create and manage the agents that place and receive calls. - name: Tools description: Custom actions an agent can call mid-call, attached per-agent. - name: MCP Servers description: >- Connect an agent to an external MCP (Model Context Protocol) server so it can call that server's tools, with static or OAuth auth. - name: Knowledge Base description: Upload files and index them into an agent's knowledge base. - name: Realtime description: >- Mint a short-lived session token to open a live voice/video WebSocket connection: the only supported way for an API-key holder to authenticate into /ws/{user_id}. - name: Webhooks description: >- Register a durable callback URL to receive call.completed and batch.completed events for every matching workspace event, and fetch the tenant signing secret used to verify X-Webhook-Signature. - name: developer-api-keys description: >- Account-management routes (create/list/revoke API keys), authenticated via dashboard login, not an API key, since they mint the credentials the rest of the developer API uses. paths: /api/v1/calls: post: tags: - Calls - developer-api summary: Create a call description: |- Initiate an outbound phone call using an agent. The agent's prompt and first_message support {{variable}} placeholders. Pass `variables` to fill them dynamically per call. Optionally override `first_message` entirely. Provide a `webhook_url` to receive a POST when the call completes. Set `provider` to "twilio" or "telnyx" to pick which provider places the call when the agent has both configured. When omitted, Twilio is used if configured, otherwise Telnyx. Pass an `Idempotency-Key` header to safely retry this request: a repeat with the same key and body replays the original response instead of placing a second call; the same key with a different body is rejected. operationId: createCall requestBody: required: true content: application/json: schema: $ref: '#/components/schemas/V1CreateCallRequest' responses: '200': description: Successful Response content: application/json: schema: $ref: '#/components/schemas/V1CreateCallResponse' '403': description: >- An agent exists with this `agent_id`, but it belongs to a different tenant. content: application/json: schema: $ref: '#/components/schemas/V1ErrorResponse' '404': description: No agent exists with this `agent_id`. content: application/json: schema: $ref: '#/components/schemas/V1ErrorResponse' '422': description: Validation Error content: application/json: schema: $ref: '#/components/schemas/HTTPValidationError' security: - ApiKeyAuth: [] components: schemas: V1CreateCallRequest: properties: agent_id: type: string title: Agent Id to_number: type: string title: To Number variables: additionalProperties: type: string type: object title: Variables default: {} first_message: anyOf: - type: string - type: 'null' title: First Message webhook_url: anyOf: - type: string - type: 'null' title: Webhook Url provider: anyOf: - type: string - type: 'null' title: Provider type: object required: - agent_id - to_number title: V1CreateCallRequest V1CreateCallResponse: properties: call_id: type: string title: Call Id call_sid: type: string title: Call Sid agent_id: type: string title: Agent Id to_number: type: string title: To Number status: type: string title: Status provider: anyOf: - type: string - type: 'null' title: Provider warnings: items: type: string type: array title: Warnings default: [] type: object required: - call_id - call_sid - agent_id - to_number - status title: V1CreateCallResponse V1ErrorResponse: properties: error: $ref: '#/components/schemas/V1ErrorDetail' type: object required: - error title: V1ErrorResponse description: |- The error envelope every `developer-api`-tagged route returns for non-2xx responses, including `422`; this overrides FastAPI's default validation-error shape. HTTPValidationError: properties: detail: items: $ref: '#/components/schemas/ValidationError' type: array title: Detail type: object title: HTTPValidationError V1ErrorDetail: properties: type: type: string title: Type code: type: string title: Code message: type: string title: Message param: anyOf: - type: string - type: 'null' title: Param request_id: anyOf: - type: string - type: 'null' title: Request Id type: object required: - type - code - message title: V1ErrorDetail ValidationError: properties: loc: items: anyOf: - type: string - type: integer type: array title: Location msg: type: string title: Message type: type: string title: Error Type input: title: Input ctx: type: object title: Context type: object required: - loc - msg - type title: ValidationError securitySchemes: ApiKeyAuth: type: http scheme: bearer description: >- A long-lived, privileged API key (`ek_...` prefix), minted once from the dashboard. Intended for trusted server-side use only; never expose it in client-side code. Send as `Authorization: Bearer ek_...`. Required by every Calls, Batches, Agents, Tools, MCP Servers, Documents, and Realtime route. ```` This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.