> ## Documentation Index > Fetch the complete documentation index at: https://docs.navtalk.ai/llms.txt > Use this file to discover all available pages before exploring further. # Issue MQTT Operator Token > Issue a short-lived MQTT operator token for Transparency Mode. Use this endpoint from a trusted backend or server-side operator agent. Pass the project API key in the `license` header. The endpoint has no request body. The returned token allows the operator to subscribe to user messages and publish replies/presence on the project-scoped transparency MQTT topics. Use this endpoint to issue a short-lived MQTT operator token for Transparency Mode. The token lets your backend or operator agent subscribe to user messages and publish replies through the NavTalk hosted MQTT broker. The endpoint does not require a request body. Pass your project API key in the `license` header. ## Python agent usage The sample operator agent fetches this token automatically when you pass `--api-key`: ```bash theme={null} python transparent_mqtt_agent.py --api-key YOUR_NAVTALK_PROJECT_API_KEY ``` Internally, the agent calls: ```python theme={null} import requests response = requests.post( "https://api.navtalk.ai/api/open/v1/mqtt/operator-token", headers={"license": "YOUR_NAVTALK_PROJECT_API_KEY"}, timeout=10, ) token_data = response.json()["data"] ``` It then uses the returned `brokerUrl`, `projectId`, `prefix`, and `token` to connect to MQTT. ## Topic usage The response includes ready-to-use topic templates: * `topics.subscribe`: subscribe to user messages, for example `navtalk/transparent/{projectId}/+/user` * `topics.reply`: publish operator replies, for example `navtalk/transparent/{projectId}/{sessionId}/reply` * `topics.presence`: publish operator online/offline status, for example `navtalk/transparent/{projectId}/agent/presence` When replying, replace `{sessionId}` with the session ID from the user message topic. ## Reply payload For a final text reply, publish this JSON to the reply topic: ```json theme={null} { "type": "transparent.reply.text", "session_id": "SESSION_ID", "roomId": "SESSION_ID", "source": "operator", "text": "Hello, how can I help you?", "messageId": "mqtt_agent_1780000000000" } ``` For streaming replies, publish `transparent.reply.text.delta` messages first, then finish with `transparent.reply.text.done`. Do not expose the returned MQTT token in browser code. Fetch it from your backend or run the Python operator agent in a trusted server environment. ## OpenAPI ````yaml POST /api/open/v1/mqtt/operator-token openapi: 3.1.0 info: title: NavTalk API description: NavTalk API for AI avatar management, file uploads, and video generation version: 1.0.0 servers: - url: https://api.navtalk.ai description: NavTalk Production Environment Server - url: https://qaapi.navtalk.ai description: NavTalk QA Environment Server - url: https://devapi.navtalk.ai description: NavTalk Development Environment Server security: - navtalkLicenseAuth: [] paths: /api/open/v1/mqtt/operator-token: post: tags: - Realtime Chat summary: Issue MQTT Operator Token description: >- Issue a short-lived MQTT operator token for Transparency Mode. Use this endpoint from a trusted backend or server-side operator agent. Pass the project API key in the `license` header. The endpoint has no request body. The returned token allows the operator to subscribe to user messages and publish replies/presence on the project-scoped transparency MQTT topics. operationId: issueMqttOperatorToken parameters: [] responses: '200': description: MQTT operator token issued successfully content: application/json: schema: $ref: '#/components/schemas/MqttOperatorTokenResponse' example: code: 200 message: SUCCESS data: brokerUrl: mqtts://mqtt.navtalk.ai:8883 projectId: project_123 prefix: navtalk/transparent authType: mqtt_operator token: eyJhbGciOi... expiresAt: '2026-07-04T10:00:00Z' expiresInSeconds: 604800 args: broker-url: mqtts://mqtt.navtalk.ai:8883 token: eyJhbGciOi... prefix: navtalk/transparent topics: subscribe: navtalk/transparent/project_123/+/user reply: navtalk/transparent/project_123/{sessionId}/reply presence: navtalk/transparent/project_123/agent/presence scriptCommand: >- python transparent_mqtt_agent.py --broker-url mqtts://mqtt.navtalk.ai:8883 --token eyJhbGciOi... --prefix navtalk/transparent '400': description: License validation failed or token issue error content: application/json: schema: $ref: '#/components/schemas/NavtalkErrorResponse' example: code: 400 message: Invalid license key security: - navtalkLicenseAuth: [] components: schemas: MqttOperatorTokenResponse: type: object properties: code: type: integer example: 200 message: type: string example: SUCCESS data: $ref: '#/components/schemas/MqttOperatorTokenData' NavtalkErrorResponse: type: object properties: code: type: integer example: 400 message: type: string example: Invalid license key MqttOperatorTokenData: type: object properties: brokerUrl: type: string description: Public MQTT broker URL used by the operator agent. example: mqtts://mqtt.navtalk.ai:8883 projectId: type: string description: Sanitized project ID used in transparency MQTT topics. example: project_123 prefix: type: string description: MQTT topic prefix for Transparency Mode. example: navtalk/transparent authType: type: string description: Token type. example: mqtt_operator token: type: string description: Short-lived MQTT operator token. Use it as the MQTT password. example: eyJhbGciOi... expiresAt: type: string format: date-time description: Token expiration time. example: '2026-07-04T10:00:00Z' expiresInSeconds: type: integer format: int64 description: Token TTL in seconds. example: 604800 args: type: object additionalProperties: type: string description: >- Command-line arguments that can be passed to the Python operator agent. example: broker-url: mqtts://mqtt.navtalk.ai:8883 token: eyJhbGciOi... prefix: navtalk/transparent topics: type: object additionalProperties: type: string description: >- MQTT topic templates for subscribing to user messages and publishing replies/presence. example: subscribe: navtalk/transparent/project_123/+/user reply: navtalk/transparent/project_123/{sessionId}/reply presence: navtalk/transparent/project_123/agent/presence scriptCommand: type: string description: Ready-to-run command for the Python sample agent. example: >- python transparent_mqtt_agent.py --broker-url mqtts://mqtt.navtalk.ai:8883 --token eyJhbGciOi... --prefix navtalk/transparent securitySchemes: navtalkLicenseAuth: type: apiKey in: header name: license description: NavTalk API license key (e.g. sk_navtalk_...) ````