> ## Documentation Index > Fetch the complete documentation index at: https://docs.osvi.ai/llms.txt > Use this file to discover all available pages before exploring further. # Send Support / Control Command > The operator control rail for a session. Send a plain `message` (delivered to the customer while a human has taken over), a control `command`, or both. Recognized commands: - `takeover` — a human operator takes over the session; the agent stops auto-replying and `mode` becomes `support`. - `tell` — inject operator guidance **and** fire an agent turn; the agent's `reply` is returned. Provide the text in `message`. - `whisper` — append private operator guidance for the next agent turn; the customer never sees it. - `end` — hand the session back to the agent (`mode` returns to `ai`). - `close` — close the session permanently. A request with only `message` and no `command` is a plain operator message, valid while the session is in `support` mode (after `takeover`). ## OpenAPI ````yaml POST /v1/chat/session/{id}/support openapi: 3.1.0 info: title: OSVI AI API description: REST API for the OSVI AI voice and chat platform license: name: MIT version: 1.0.0 servers: - url: https://api.osvi.ai security: - ApiToken: [] paths: /v1/chat/session/{id}/support: post: summary: Send support / control command description: >- The operator control rail for a session. Send a plain `message` (delivered to the customer while a human has taken over), a control `command`, or both. Recognized commands: - `takeover` — a human operator takes over the session; the agent stops auto-replying and `mode` becomes `support`. - `tell` — inject operator guidance **and** fire an agent turn; the agent's `reply` is returned. Provide the text in `message`. - `whisper` — append private operator guidance for the next agent turn; the customer never sees it. - `end` — hand the session back to the agent (`mode` returns to `ai`). - `close` — close the session permanently. A request with only `message` and no `command` is a plain operator message, valid while the session is in `support` mode (after `takeover`). parameters: - name: id in: path required: true description: The session UUID (from Create Session or Get Active Session). schema: type: string example: 4718a326-417b-4dda-90d0-21fd65a11cb8 requestBody: required: true content: application/json: schema: type: object properties: command: type: string enum: - takeover - tell - whisper - end - close description: >- Control command to apply. Omit to send a plain operator message (requires the session to be in `support` mode). example: close message: type: string description: >- Message text. Required for a plain operator message and for the `tell` command; optional context for `takeover`. example: A human agent is joining the conversation. examples: plain_message: summary: Plain operator message value: message: A human agent is joining the conversation. close: summary: Close the session value: command: close takeover: summary: Human takeover value: command: takeover tell: summary: Tell (guide the agent and reply) value: command: tell message: Thanks, I can help with that. responses: '200': description: >- Command accepted. The response `data` always includes `state`, `session_id`, and `command`; additional fields depend on the command (e.g. `reply` for `tell`, `active_human` for `takeover`). content: application/json: schema: type: object properties: success: type: boolean example: true data: type: object properties: state: type: string description: >- Outcome of the command — `ok` on success, or a status such as `no_change`, `busy`, `dormant`, `rejected`, `disabled`, `invalid`, or `timeout`. example: ok session_id: type: string example: 4718a326-417b-4dda-90d0-21fd65a11cb8 command: type: string nullable: true description: >- Echo of the command issued. `null` for a plain operator message. example: close reply: type: string nullable: true description: Agent reply — present for the `tell` command. example: Of course, let me pull that up for you. active_human: type: string nullable: true description: >- Email of the operator now holding the session — present for `takeover`. example: agent@yourco.com '401': description: Invalid or missing API token content: application/json: schema: $ref: '#/components/schemas/ChatV1Error' '403': description: >- The requested command is disabled for this agent (`command_disabled`). content: application/json: schema: $ref: '#/components/schemas/ChatV1Error' '404': description: No session matches the given `id` (`session_not_found`). content: application/json: schema: $ref: '#/components/schemas/ChatV1Error' '422': description: >- The chat engine rejected the command (e.g. wrong mode for a plain message, or empty `tell` text). content: application/json: schema: $ref: '#/components/schemas/ChatV1EngineError' '502': description: The chat engine could not be reached or returned an error. content: application/json: schema: $ref: '#/components/schemas/ChatV1EngineError' components: schemas: ChatV1Error: type: object properties: success: type: boolean example: false error: type: string description: Machine-readable error code or message. example: agent_not_found ChatV1EngineError: type: object description: >- Returned when the upstream chat engine rejects or fails a proxied request. properties: success: type: boolean example: false error: type: string example: Python engine returned 422 for POST /v1/chat/session/{id}/support upstream_body: type: object nullable: true description: Parsed error body returned by the chat engine, when available. example: state: rejected reason: tell_not_allowed_during_takeover securitySchemes: ApiToken: type: apiKey in: header name: API-Token description: >- 16-character API token associated with your OSVI account. Find it in your dashboard under Settings → API. ````