> ## Documentation Index > Fetch the complete documentation index at: https://docs.vatel.ai/llms.txt > Use this file to discover all available pages before exploring further. # Connection > Bidirectional voice agent session. Connect with `?token={jwt}` where the JWT is obtained from `POST /v1/session-token`. ## AsyncAPI ````yaml asyncapi.json connection id: connection title: Voice session description: >- Bidirectional voice agent session. Connect with `?token={jwt}` where the JWT is obtained from `POST /v1/session-token`. servers: - id: production protocol: wss host: api.vatel.ai bindings: [] variables: [] address: /v1/connection parameters: [] bindings: [] operations: - &ref_1 id: voiceSessionSendToServer title: 'Voice session: send to server' description: Client messages for `/v1/connection` type: receive messages: - &ref_3 id: InputAudio contentType: application/json payload: - name: Input audio description: Client sends captured audio to the server (base64). type: object properties: - name: type type: string description: input_audio required: true - name: data type: object required: true properties: - name: audio type: string description: Base64-encoded audio in PCM 16 24000Hz mono required: true headers: [] jsonPayloadSchema: type: object required: - type - data properties: type: type: string const: input_audio x-parser-schema-id: data: type: object required: - audio properties: audio: type: string description: Base64-encoded audio in PCM 16 24000Hz mono x-parser-schema-id: x-parser-schema-id: x-parser-schema-id: title: Input audio description: Client sends captured audio to the server (base64). example: |- { "type": "", "data": { "audio": "" } } bindings: [] extensions: - id: x-parser-unique-object-id value: InputAudio - &ref_4 id: ToolCallOutput contentType: application/json payload: - name: Tool call output description: Client sends the result of a tool call requested by the server. type: object properties: - name: type type: string description: tool_call_output required: true - name: data type: object required: true properties: - name: toolCallId type: string required: true - name: output type: string required: true headers: [] jsonPayloadSchema: type: object required: - type - data properties: type: type: string const: tool_call_output x-parser-schema-id: data: type: object required: - toolCallId - output properties: toolCallId: type: string x-parser-schema-id: output: type: string x-parser-schema-id: x-parser-schema-id: x-parser-schema-id: title: Tool call output description: Client sends the result of a tool call requested by the server. example: |- { "type": "", "data": { "toolCallId": "", "output": "" } } bindings: [] extensions: - id: x-parser-unique-object-id value: ToolCallOutput bindings: [] extensions: &ref_0 - id: x-parser-unique-object-id value: connection - &ref_2 id: voiceSessionReceiveFromServer title: 'Voice session: receive from server' description: Server messages for `/v1/connection` type: send messages: - &ref_5 id: ServerMessage contentType: application/json payload: - name: Server message description: >- Discriminated by type; payload in data. One of: session_started, response_audio, response_text, input_audio_transcript, speech_started, speech_stopped, session_ended, interruption, tool_call. type: object properties: - name: type type: string enumValues: - session_started - response_audio - response_text - input_audio_transcript - speech_started - speech_stopped - session_ended - interruption - tool_call required: true headers: [] jsonPayloadSchema: type: object required: - type properties: type: type: string enum: - session_started - response_audio - response_text - input_audio_transcript - speech_started - speech_stopped - session_ended - interruption - tool_call x-parser-schema-id: data: x-parser-schema-id: x-parser-schema-id: title: Server message description: >- Discriminated by type; payload in data. One of: session_started, response_audio, response_text, input_audio_transcript, speech_started, speech_stopped, session_ended, interruption, tool_call. example: |- { "type": "" } bindings: [] extensions: - id: x-parser-unique-object-id value: ServerMessage - &ref_6 id: SessionStarted contentType: application/json payload: - name: Session started description: Sent when the call session has started. type: object properties: - name: type type: string description: session_started required: true - name: data type: object required: true properties: - name: id type: string required: true headers: [] jsonPayloadSchema: type: object required: - type - data properties: type: type: string const: session_started x-parser-schema-id: data: type: object required: - id properties: id: type: string x-parser-schema-id: x-parser-schema-id: x-parser-schema-id: title: Session started description: Sent when the call session has started. example: |- { "type": "", "data": { "id": "" } } bindings: [] extensions: - id: x-parser-unique-object-id value: SessionStarted - &ref_7 id: ResponseAudio contentType: application/json payload: - name: Response audio description: Streamed TTS audio chunk for the current turn. type: object properties: - name: type type: string description: response_audio required: true - name: data type: object required: true properties: - name: turn_id type: string description: Turn or playback context id for this audio stream. required: true - name: audio type: string description: Base64-encoded PCM16 audio. required: true - name: is_final type: boolean description: >- True when this is the last chunk for this utterance or segment. required: true headers: [] jsonPayloadSchema: type: object required: - type - data properties: type: type: string const: response_audio x-parser-schema-id: data: type: object required: - turn_id - audio - is_final properties: turn_id: type: string description: Turn or playback context id for this audio stream. x-parser-schema-id: audio: type: string description: Base64-encoded PCM16 audio. x-parser-schema-id: is_final: type: boolean description: >- True when this is the last chunk for this utterance or segment. x-parser-schema-id: x-parser-schema-id: x-parser-schema-id: title: Response audio description: Streamed TTS audio chunk for the current turn. example: |- { "type": "", "data": { "turn_id": "", "audio": "", "is_final": true } } bindings: [] extensions: - id: x-parser-unique-object-id value: ResponseAudio - &ref_8 id: ResponseText contentType: application/json payload: - name: Response text description: >- Agent text for the current turn; may repeat or refine while is_final is false. type: object properties: - name: type type: string description: response_text required: true - name: data type: object required: true properties: - name: turn_id type: string description: Turn id associated with this assistant message. required: true - name: text type: string description: >- Assistant text (may repeat or refine while is_final is false). required: true - name: is_final type: boolean description: True when this text is committed for the turn. required: true headers: [] jsonPayloadSchema: type: object required: - type - data properties: type: type: string const: response_text x-parser-schema-id: data: type: object required: - turn_id - text - is_final properties: turn_id: type: string description: Turn id associated with this assistant message. x-parser-schema-id: text: type: string description: >- Assistant text (may repeat or refine while is_final is false). x-parser-schema-id: is_final: type: boolean description: True when this text is committed for the turn. x-parser-schema-id: x-parser-schema-id: x-parser-schema-id: title: Response text description: >- Agent text for the current turn; may repeat or refine while is_final is false. example: |- { "type": "", "data": { "turn_id": "", "text": "", "is_final": true } } bindings: [] extensions: - id: x-parser-unique-object-id value: ResponseText - &ref_9 id: InputAudioTranscript contentType: application/json payload: - name: Input audio transcript description: >- User speech transcript from STT; false is_final for interim hypotheses. type: object properties: - name: type type: string description: input_audio_transcript required: true - name: data type: object required: true properties: - name: transcript type: string description: Recognized user speech. required: true - name: turn_id type: string description: Turn id when provided. required: false - name: is_final type: boolean description: False for interim hypotheses; true for final transcript. required: true headers: [] jsonPayloadSchema: type: object required: - type - data properties: type: type: string const: input_audio_transcript x-parser-schema-id: data: type: object required: - transcript - is_final properties: transcript: type: string description: Recognized user speech. x-parser-schema-id: turn_id: type: string description: Turn id when provided. x-parser-schema-id: is_final: type: boolean description: False for interim hypotheses; true for final transcript. x-parser-schema-id: x-parser-schema-id: x-parser-schema-id: title: Input audio transcript description: >- User speech transcript from STT; false is_final for interim hypotheses. example: |- { "type": "", "data": { "transcript": "", "turn_id": "", "is_final": true } } bindings: [] extensions: - id: x-parser-unique-object-id value: InputAudioTranscript - &ref_10 id: SpeechStarted contentType: application/json payload: - name: Speech started description: Sent when user speech (VAD) has started. type: object properties: - name: type type: string description: speech_started required: true - name: data type: object required: false properties: - name: emulated type: boolean description: >- When true, speech activity was driven by transcript (e.g. STT text) rather than raw audio, which turned VAD on as if the user had started speaking. required: true headers: [] jsonPayloadSchema: type: object required: - type properties: type: type: string const: speech_started x-parser-schema-id: data: type: object required: - emulated properties: emulated: type: boolean description: >- When true, speech activity was driven by transcript (e.g. STT text) rather than raw audio, which turned VAD on as if the user had started speaking. x-parser-schema-id: x-parser-schema-id: x-parser-schema-id: title: Speech started description: Sent when user speech (VAD) has started. example: |- { "type": "", "data": { "emulated": true } } bindings: [] extensions: - id: x-parser-unique-object-id value: SpeechStarted - &ref_11 id: SpeechStopped contentType: application/json payload: - name: Speech stopped description: Sent when user speech (VAD) has stopped. type: object properties: - name: type type: string description: speech_stopped required: true headers: [] jsonPayloadSchema: type: object required: - type properties: type: type: string const: speech_stopped x-parser-schema-id: x-parser-schema-id: title: Speech stopped description: Sent when user speech (VAD) has stopped. example: |- { "type": "" } bindings: [] extensions: - id: x-parser-unique-object-id value: SpeechStopped - &ref_12 id: SessionEnded contentType: application/json payload: - name: Session ended description: Sent when the call session has ended. type: object properties: - name: type type: string description: session_ended required: true - name: data type: object required: false headers: [] jsonPayloadSchema: type: object required: - type properties: type: type: string const: session_ended x-parser-schema-id: data: type: object x-parser-schema-id: x-parser-schema-id: title: Session ended description: Sent when the call session has ended. example: No examples found bindings: [] extensions: - id: x-parser-unique-object-id value: SessionEnded - &ref_13 id: Interruption contentType: application/json payload: - name: Interruption description: Sent when user has interrupted the agent. type: object properties: - name: type type: string description: interruption required: true headers: [] jsonPayloadSchema: type: object required: - type properties: type: type: string const: interruption x-parser-schema-id: x-parser-schema-id: title: Interruption description: Sent when user has interrupted the agent. example: |- { "type": "" } bindings: [] extensions: - id: x-parser-unique-object-id value: Interruption - &ref_14 id: ToolCall contentType: application/json payload: - name: Tool call description: >- Server requests the client to execute a tool and respond with tool_call_output. type: object properties: - name: type type: string description: tool_call required: true - name: data type: object required: true properties: - name: toolCallId type: string description: >- Opaque id for this invocation; echo it in tool_call_output so the server can correlate the result. required: true - name: toolName type: string description: Name of the tool to run on the client. required: true - name: arguments type: array description: >- Structured parameters for this tool call, each with schema metadata and the value supplied for this turn. required: true properties: - name: name type: string description: Parameter name as defined by the tool schema. required: false - name: type type: string description: Static, dynamic or resolved type of the parameter. required: false - name: dataType type: string description: Data type of the value. required: false - name: description type: string description: >- Human-readable explanation of what this parameter means. required: false - name: description type: string description: >- Concrete value for this invocation; type depends on dataType and tool contract. required: false headers: [] jsonPayloadSchema: type: object required: - type - data properties: type: type: string const: tool_call x-parser-schema-id: data: type: object required: - toolCallId - toolName - arguments properties: toolCallId: type: string description: >- Opaque id for this invocation; echo it in tool_call_output so the server can correlate the result. x-parser-schema-id: toolName: type: string description: Name of the tool to run on the client. x-parser-schema-id: arguments: type: array description: >- Structured parameters for this tool call, each with schema metadata and the value supplied for this turn. items: type: object properties: name: type: string description: Parameter name as defined by the tool schema. x-parser-schema-id: type: type: string description: Static, dynamic or resolved type of the parameter. x-parser-schema-id: dataType: type: string description: Data type of the value. x-parser-schema-id: description: type: string description: >- Human-readable explanation of what this parameter means. x-parser-schema-id: required: type: boolean description: >- Whether the tool schema marks this parameter as required. x-parser-schema-id: value: description: >- Concrete value for this invocation; type depends on dataType and tool contract. x-parser-schema-id: x-parser-schema-id: x-parser-schema-id: x-parser-schema-id: x-parser-schema-id: title: Tool call description: >- Server requests the client to execute a tool and respond with tool_call_output. example: No examples found bindings: [] extensions: - id: x-parser-unique-object-id value: ToolCall bindings: [] extensions: *ref_0 sendOperations: - *ref_1 receiveOperations: - *ref_2 sendMessages: - *ref_3 - *ref_4 receiveMessages: - *ref_5 - *ref_6 - *ref_7 - *ref_8 - *ref_9 - *ref_10 - *ref_11 - *ref_12 - *ref_13 - *ref_14 extensions: - id: x-parser-unique-object-id value: connection securitySchemes: [] ````