Server events - Alibaba Cloud Model Studio

error

Server error.

event_idstringA unique identifier for this event.typestringThe event type. This value is always error.errorobjectError details.

Properties

typestringThe error type.codestringThe error code.messagestringThe error message.paramstringThe parameter associated with the error, such as session.modalities.

{
  "event_id": "event_RoUu4T8yExPMI37GKwaOC",
  "type": "error",
  "error": {
    "type": "invalid_request_error",
    "code": "invalid_value",
    "message": "Invalid modalities: ['audio']. Supported combinations are: ['text'] and ['audio', 'text'].",
    "param": "session.modalities"
  }
}

session.created

Returned when a client connects. Contains the default session configuration.

event_idstringA unique identifier for this event.typestringThe event type. This value is always session.created.sessionobjectThe session configuration.

Properties

objectstringThis value is always realtime.session.modelstringThe model used.modalitiesarrayThe output modalities for the model.voicestringThe voice for model-generated audio.input_audio_formatstringInput audio format. Only pcm is supported (16 kHz sample rate).output_audio_formatstringOutput audio format. Only pcm is supported (24 kHz sample rate).input_audio_transcriptionobjectThe transcription configuration.

Properties

modelstringTranscription model. Always qwen3-asr-flash-realtime. Not configurable.

turn_detectionobjectThe voice activity detection (VAD) configuration.

Properties

typestringThe VAD type. Valid values are server_vad (default) or semantic_vad. See Client events.thresholdfloatThe VAD detection threshold.silence_duration_msintegerSilence duration (ms) that triggers end-of-speech detection.idle_timeout_msintegerThe idle timeout in milliseconds. Returned only in server_vad mode with qwen3.5-omni-plus-realtime or qwen3.5-omni-flash-realtime models.

enable_searchbooleanWhether to enable web search. Supported by Qwen3.8-Omni-Flash-Realtime and Qwen3.5-Omni-Realtime models.search_optionsobjectThe options for the web search.temperaturefloatThe temperature parameter for the model.

The following example is the default session returned by qwen3.8-omni-flash-realtime in the Beijing region.

{
    "event_id": "event_QQubXbhHMyXmKaSuE6PQ8",
    "type": "session.created",
    "session": {
        "input_audio_format": "pcm",
        "input_audio_transcription": {
            "model": "qwen3-asr-flash-realtime"
        },
        "id": "sess_MjEctgJ4ziXPEioCzSSvK",
        "object": "realtime.session",
        "modalities": [
            "text",
            "audio"
        ],
        "turn_detection": {
            "type": "server_vad",
            "silence_duration_ms": 800,
            "interrupt_response": true,
            "create_response": true,
            "threshold": 0.5,
            "prefix_padding_ms": 300
        },
        "model": "qwen3.8-omni-flash-realtime",
        "voice": "Tina",
        "output_audio_format": "pcm"
    }
}

session.updated

Returned after a successful session.update request. On failure, an error event is returned instead.

event_idstringA unique identifier for this event.typestringThe event type. This value is always session.updated.sessionobjectThe session configuration.

Properties

temperaturefloatThe temperature parameter for the model.modalitiesarrayThe output modalities for the model.voicestringThe voice for model-generated audio.instructionsstringThe model's goal and role.input_audio_formatstringInput audio format. Only pcm is supported (16 kHz sample rate).output_audio_formatstringOutput audio format. Only pcm is supported (24 kHz sample rate).input_audio_transcriptionobjectThe transcription configuration.

Properties

modelstringTranscription model. Always qwen3-asr-flash-realtime. Not configurable.

turn_detectionobjectThe voice activity detection (VAD) configuration.

Properties

enable_searchboolean (optional)Whether to enable web search. Supported by Qwen3.8-Omni-Flash-Realtime and Qwen3.5-Omni-Realtime models.search_optionsobject (optional)The web search options.toolsarray (optional)Tool definitions. The properties below describe Function Calling tools with type="function". See client tool configuration for Qwen3.8-Omni-Flash-Realtime MCP fields; MCP endpoints and credentials are not echoed in session.updated.

Properties

typestring (required)This value is always function.function.namestring (required)The function name, such as get_current_weather or get_current_time.function.descriptionstring (optional)Description of the function's purpose. The model uses this to decide whether to call the function.function.parametersobject (optional)Input parameter schema. The model uses this to extract parameters. Omit if the function takes no parameters.

Properties

typestring (required)This value is always object.propertiesobject (optional)Each key is a parameter name mapped to an object with type and description.requiredarray (optional)Specifies which input parameters are required.

top_pfloatThe probability threshold for nucleus sampling.top_kintegerCandidate set size for sampling during generation.max_tokensintegerMaximum tokens the model can return for this request.repetition_penaltyfloatControls repetition in consecutive sequences during generation.presence_penaltyfloatControls repetition in generated content.seedintegerThe degree of consistency in the model's output per request.

The following example uses qwen3.8-omni-flash-realtime in the Beijing region, with text-only output and max_tokens=32.

{
    "event_id": "event_TSBGI9Yj5ecCKjiGO34VB",
    "type": "session.updated",
    "session": {
        "id": "sess_MjEctgJ4ziXPEioCzSSvK",
        "object": "realtime.session",
        "model": "qwen3.8-omni-flash-realtime",
        "modalities": [
            "text"
        ],
        "instructions": "请只回复 OK。",
        "voice": "Tina",
        "input_audio_format": "pcm",
        "output_audio_format": "pcm",
        "input_audio_transcription": {
            "model": "qwen3-asr-flash-realtime"
        },
        "max_tokens": 32
    }
}

input_audio_buffer.speech_started

In VAD mode, returned when the server detects speech onset in the audio buffer.

May be triggered each time audio is added to the buffer before speech is detected.

event_idstringA unique identifier for this event.typestringThe event type. This value is always input_audio_buffer.speech_started.audio_start_msintegerTime (ms) from when audio buffer writing starts until speech is first detected.item_idstringID of the user message item created when end-of-speech is detected.

User message items append user input to the conversation history for model inference.

{
    "event_id": "event_Pvp8nEhsQuGCQbFJ9x58n",
    "type": "input_audio_buffer.speech_started",
    "audio_start_ms": 3647,
    "item_id": "item_YbAiGvK2H7YaS34o4R6Ba"
}

input_audio_buffer.speech_stopped

In VAD mode, returned when the server detects end-of-speech in the audio buffer. Also returns a conversation.item.created event with the corresponding user message item.

event_idstringA unique identifier for this event.typestringThe event type. This value is always input_audio_buffer.speech_stopped.audio_end_msintegerTime (ms) from session start until end-of-speech is detected.item_idstringThe ID of the user message item that will be created.

{
    "event_id": "event_UhQiqNVRsgUiq4KUS5Xb5",
    "type": "input_audio_buffer.speech_stopped",
    "audio_end_ms": 4453,
    "item_id": "item_YbAiGvK2H7YaS34o4R6Ba"
}

input_audio_buffer.committed

Returned when the input audio buffer is committed.

In VAD mode, the server automatically commits the buffer when it detects end-of-speech.
In Manual mode, returned after the client sends an input_audio_buffer.commit event.

event_idstringA unique identifier for this event.typestringThe event type. This value is always input_audio_buffer.committed.item_idstringThe ID of the user message item that will be created.

{
    "event_id": "event_Iy6sUzL1nmdFgshFYxJEz",
    "type": "input_audio_buffer.committed",
    "item_id": "item_YbAiGvK2H7YaS34o4R6Ba"
}

input_audio_buffer.cleared

Returned after the client sends an input_audio_buffer.clear event.

event_idstringA unique identifier for this event.typestringThe event type. This value is always input_audio_buffer.cleared.

{
  "event_id": "event_RoUu4T8yExPMI37GKwaOC",
  "type": "input_audio_buffer.cleared"
}

conversation.item.created

Returned when a conversation item is created.

event_idstringA unique identifier for this event.typestringThe event type. This value is always conversation.item.created.response_idstring (conditionally required)Returned only when item.type is mcp_approval_request; identifies the parent Response that generated the MCP call.item_idstring (conditionally required)Returned only when item.type is mcp_approval_request; the approval item ID, equal to item.id.previous_item_idstring (conditionally required)Returned only when item.type is mcp_approval_request; identifies the mcp_call item under review.itemobjectThe conversation item to add.

Properties

idstringThe unique ID of the conversation item.objectstringFor message and function_call items, this field is realtime.item. For MCP items, it has the same value when returned.statusstringWhen returned, this field indicates the conversation item status. An initial mcp_call item requires it with the value in_progress.rolestringPresent only on message items; identifies the message role.contentarray of objectsThe content of the message, returned when the type is message. The following fields describe the array element in this example.

Array item

typestringThe content-part type; input_audio in this example.

typestringThe conversation item type includes message and function_call. Qwen3.8-Omni-Flash-Realtime also returns mcp_list_tools, mcp_call, and mcp_approval_request; see MCP item examples.namestringThe name of the function that is called when the type is function_call.call_idstringWhen the type is function_call, this is the unique ID of the function invocation.argumentsstringWhen the type is function_call, this parameter contains the arguments for the function invocation as a JSON string.

type=mcp_list_tools

For this item type, item.id matches the item_id in tool discovery status events.server_labelstring (required)Identifies the MCP server.toolsarray of objects (required)Validated tool definitions after allowed_tools filtering; empty if discovery fails.

Array item

namestring (required)Original tool name, 1–64 characters using letters, digits, underscores, periods, or hyphens.descriptionstring (optional)Tool description from the MCP server.input_schemaobject (required)JSON Schema from the MCP server. The service does not perform full JSON Schema semantic validation; the MCP server ultimately validates arguments.

Properties

typestring (required)The root value must be object.propertiesobject (optional)List each parameter under its custom name. For example, city in the mcp_list_tools example is a parameter name; its type and description describe the data type and purpose. The MCP server defines each parameter's JSON Schema.requiredarray of strings (optional)Names of required parameters.Other standard JSON Schema fields, including additionalProperties, $defs, oneOf, anyOf, and allOf, pass through from the original schema.

annotationsobject (optional)ToolAnnotations from the MCP server. The following MCP standard hint fields are optional; the server determines which fields it returns.

Properties

titlestring (optional)Display name of the tool.readOnlyHintboolean (optional)Hints whether the tool is read-only.destructiveHintboolean (optional)Hints whether the tool may make destructive changes.idempotentHintboolean (optional)Hints whether repeated calls have no additional effect.openWorldHintboolean (optional)Hints whether the tool may interact with external systems. These fields are hints and must not be used as a security guarantee.

errorobject (optional)Returned on discovery failure.

Properties

typestring (required)Must be tool_execution_error.messagestring (required)A client-safe description without sensitive upstream response content.

type=mcp_call (initial item)

objectstring (required)Must be realtime.item.statusstring (required)Initially in_progress.server_labelstring (required)Identifies the MCP server executing the tool.namestring (required)Original tool name.call_idstring (required)Unique ID of this call.argumentsstring (required)Usually empty initially; use later events and the final item for full arguments.

type=mcp_approval_request

Copy this approval item's item.id unchanged into approval_request_id when replying.server_labelstring (required)Identifies the MCP server for the pending tool.namestring (required)Original name of the pending tool.argumentsstring (required)Full JSON string of arguments awaiting approval.call_idstring (required)ID of the call awaiting approval.

Example:

{
    "event_id": "event_JEfkrr9gO3Ny7Xcv9bGVd",
    "type": "conversation.item.created",
    "item": {
        "id": "item_YbAiGvK2H7YaS34o4R6Ba",
        "object": "realtime.item",
        "type": "message",
        "status": "in_progress",
        "role": "assistant",
        "content": [
            {
                "type": "input_audio"
            }
        ]
    }
}
// Tool calling scenario
{
    "event_id": "event_S1hkaIQgcuQD8OEdOpGHQ",
    "type": "conversation.item.created",
    "item": {
        "id": "item_FEG9qJGNkPcdf4et3p7BV",
        "object": "realtime.item",
        "type": "function_call",
        "status": "in_progress",
        "call_id": "call_bc0a7fb7235840f69ecfe4",
        "name": "get_current_weather",
        "arguments": ""
    }
}

conversation.item.input_audio_transcription.delta

Sent frequently while the user is speaking when input audio transcription is enabled. Provides real-time intermediate transcription results. Concatenate text + stash for the most complete sentence preview at any point.

event_idstringA unique identifier for this event.typestringThe event type. This value is always conversation.item.input_audio_transcription.delta.item_idstringThe ID of the associated conversation item.content_indexintegerThe index of the content part that contains the audio.textstringConfirmed text prefix — the portion the model has finalized and will not change.stashstringPreliminary text suffix — a temporary draft following the confirmed portion, subject to revision.languagestringThe detected language of the recognized audio.emotionstringThe detected emotion of the recognized audio. Valid values: neutral, happy, sad, angry, surprised, disgusted, fearful.

{
    "event_id": "event_C7jzoeSFuiwOZS6tR14yx",
    "type": "conversation.item.input_audio_transcription.delta",
    "item_id": "item_ThVYhLHOdeXb4bBSvzSFF",
    "content_index": 0,
    "text": "",
    "stash": "How is the weather today?",
    "language": "en",
    "emotion": "neutral",
    "obfuscation": "ABEXGYmxdmc97u"
}

To get the most complete sentence preview at any moment, concatenate these two fields: real-time preview = text + stash.

Click to view example

Suppose the user is saying: "The weather is nice today, sunny and warm."The following shows the event stream you might receive and how to interpret them:

Time	User speech progress	API response (text and stash)	Client UI display (text + stash)
T1	"The weather..."	text: "" stash: "The weather"	The weather
T2	"...is nice..."	text: "" stash: "The weather is nice"	The weather is nice
T3	"...today,"	text: "The weather" stash: " is nice today,"	The weather is nice today, ("The weather" has been confirmed and moved to text)
T4	(brief pause)	text: "The weather is nice today, " stash: ""	The weather is nice today, (first clause fully confirmed)
T5	"sunny..."	text: "The weather is nice today, " stash: "sunny"	The weather is nice today, sunny
T6	"...and warm."	text: "The weather is nice today, " stash: "sunny and warm."	The weather is nice today, sunny and warm.
T7	(stops speaking)	-	Use the transcript from conversation.item.input_audio_transcription.completed as the final result.

conversation.item.input_audio_transcription.completed

Indicates that the user's audio has been transcribed by the built-in speech recognition model (qwen3-asr-flash-realtime). Not configurable.

The transcribed text from the speech recognition model may differ from the interpretation generated by the Qwen-Omni-Realtime model. The transcription is for reference only.

event_idstringA unique identifier for this event.typestringThe event type. This value is always conversation.item.input_audio_transcription.completed.item_idstringThe ID of the user message item.content_indexintegerThis value is always 0.transcriptstringThe transcribed text.

{
    "event_id": "event_FrrZcxiDfTB9LD9p4pVng",
    "type": "conversation.item.input_audio_transcription.completed",
    "item_id": "item_YbAiGvK2H7YaS34o4R6Ba",
    "content_index": 0,
    "transcript": "Hello."
}

conversation.item.input_audio_transcription.failed

Returned when input audio transcription is enabled and the transcription fails. Independent of the error event; helps clients identify transcription failures specifically.

event_idstringA unique identifier for this event.typestringThe event type. This value is always conversation.item.input_audio_transcription.failed.item_idstringThe ID of the user message item.content_indexintegerThis value is always 0.errorobjectThe error information.

Properties

code stringThe error code.message stringThe error message.param stringThe parameter related to the error.

{
  "type": "conversation.item.input_audio_transcription.failed",
  "item_id": "<item_id>",
  "content_index": 0,
  "error": {
    "code": "<code>",
    "message": "<message>",
    "param": "<param>"
  }
}

response.created

Returned when the server starts generating a new response.

event_idstringA unique identifier for this event.typestringThe event type. This value is always response.created.responseobjectThe response object.

Properties

id stringThe unique ID of the response.conversation_id stringThe unique ID of the current session.object stringThe object type. For this event, this value is always realtime.response.status stringThe response status. Valid values are completed, failed, in_progress, or incomplete.modalities arrayThe response modalities.voice stringThe voice for model-generated audio.output arrayThis field is empty for this event.

{
    "event_id": "event_XuDavMzQN3KKepqGu3KRh",
    "type": "response.created",
    "response": {
        "id": "resp_HaVOPdbmX6vifiV5pAfJY",
        "object": "realtime.response",
        "conversation_id": "conv_FjJaccpnvwHNo9cPVuzGc",
        "status": "in_progress",
        "modalities": [
            "text",
            "audio"
        ],
        "voice": "Cherry",
        "output_audio_format": "pcm",
        "output": []
    }
}

response.done

Returned after the response is fully generated. The response object includes all output items except raw audio data.

event_idstringA unique identifier for this event.typestringThe event type. This value is always response.done.responseobjectThe response object.

Properties

id stringThe unique ID of the response.conversation_id stringThe unique ID of the current session.object stringThe object type. For this event, this value is always realtime.response.status stringThe response status.modalities arrayThe response modalities.voice stringThe voice for model-generated audio.output arrayThe response output items. Each array element is a conversation item object.

Array item

id stringThe ID of the response output.type stringThe type of the output item. Values include message and function_call. Qwen3.8-Omni-Flash-Realtime also supports mcp_call; see MCP item examples.object stringFor message and function_call items, this field is realtime.item. For MCP items, it has the same value when returned.status stringThe output item status.role stringPresent only on message items; identifies the message role.content arrayThe output item content, returned only when type is message. Each array element is a content-part object.

Array item

type stringThe content type. The value can be text for plain text output or audio for audio output.text stringThe text output.transcript stringThe text transcript of the audio.

name stringThe name of the function that is invoked when the type is function_call.call_id stringWhen the type is function_call, this is the unique ID of the function invocation.arguments stringWhen the type is function_call, this field contains the full arguments for the function call as a JSON string.

type=mcp_call (final item)

statusstring (required)completed or failed.server_labelstring (required)Identifies the MCP server that executed the tool.namestring (required)Original tool name.call_idstring (required)Unique ID of this call.argumentsstring (required)Full JSON string of arguments.outputstring (optional)A JSON string serialized from MCP tools/call.result. It may also appear in some failure cases.errorobject (optional)Returned on failure.

Properties

typestring (required)Must be tool_execution_error.messagestring (required)A client-safe description without sensitive upstream response content.

If the MCP server returns isError=true, the final status is failed and the original output may also be present.

usage objectToken usage details for this response.

Properties

total_tokens integerTotal tokens used in this response.input_tokens integerNumber of input tokens.output_tokens integerNumber of output tokens.input_tokens_details objectDetails about input token usage, including text_tokens and audio_tokens.output_tokens_details objectDetails about output token usage, including text_tokens and audio_tokens.plugins object (optional)Plugin usage metrics. Returned when web search (enable_search) is enabled.

Properties

search objectSearch metering data.

Properties

count integerThe number of searches.strategy stringThe search strategy.

Example:

{
    "event_id": "event_CSaxRRYLvbrfexDXAEuDG",
    "type": "response.done",
    "response": {
        "id": "resp_HaVOPdbmX6vifiV5pAfJY",
        "object": "realtime.response",
        "conversation_id": "conv_FjJaccpnvwHNo9cPVuzGc",
        "status": "completed",
        "modalities": [
            "text",
            "audio"
        ],
        "voice": "Cherry",
        "output_audio_format": "pcm",
        "output": [
            {
                "id": "item_Ls6MtCUWO7LM4E59QziNv",
                "object": "realtime.item",
                "type": "message",
                "status": "completed",
                "role": "assistant",
                "content": [
                    {
                        "type": "audio",
                        "transcript": "Hello! How can I help you?"
                    }
                ]
            }
        ],
        "usage": {
            "total_tokens": 377,
            "input_tokens": 336,
            "output_tokens": 41,
            "input_tokens_details": {
                "text_tokens": 228,
                "audio_tokens": 108
            },
            "output_tokens_details": {
                "text_tokens": 9,
                "audio_tokens": 32
            },
            "plugins": {
                "search": {
                    "count": 1,
                    "strategy": "agent"
                }
            }
        }
    }
}
// Tool calling scenario
{
    "event_id": "event_T1EFAJp43X2DWtDRmxTtx",
    "type": "response.done",
    "response": {
        "id": "resp_TucN5QgymL5MA8vkJvFlS",
        "object": "realtime.response",
        "conversation_id": "conv_SEDZESRlefT8WvLSmEn6E",
        "status": "completed",
        "modalities": ["text", "audio"],
        "voice": "Ethan",
        "output_audio_format": "pcm",
        "output": [
            {
                "id": "item_FEG9qJGNkPcdf4et3p7BV",
                "object": "realtime.item",
                "type": "function_call",
                "status": "completed",
                "call_id": "call_bc0a7fb7235840f69ecfe4",
                "name": "get_current_weather",
                "arguments": " {\"location\": \"Hangzhou\"}"
            }
        ],
        "usage": {
            "total_tokens": 567,
            "input_tokens": 524,
            "output_tokens": 43,
            "input_tokens_details": {
                "text_tokens": 487,
                "audio_tokens": 37
            },
            "output_tokens_details": {
                "text_tokens": 43
            }
        }
    }
}

response.text.delta

Returned when the output modality is text-only and the model generates new text incrementally.

event_idstringA unique identifier for this event.typestringThe event type. This value is always response.text.delta.deltastringIncremental text generated by the model.response_idstringThe response ID.item_idstringThe message item ID.output_indexintegerThe index of the output item in the response. This value is always 0.content_indexintegerThe index of the internal part within the output item. This value is always 0.

{
    "delta": "Hello",
    "event_id": "event_TH49MauuPmRo1RGaMSlP7",
    "type": "response.text.delta",
    "response_id": "resp_PrRSvPVpnCExdUOGHHLuP",
    "item_id": "item_L8IRm9kRXFpxoOjDqDC96",
    "output_index": 0,
    "content_index": 0
}

response.text.done

Returned when the output modality is text-only and the model finishes generating text.

Also returned if the response is interrupted, incomplete, or canceled.

event_idstringA unique identifier for this event.typestringThe event type. This value is always response.text.done.response_idstringThe response ID.item_idstringThe message item ID.output_indexintegerThe index of the output item in the response.content_indexintegerThe index of the output item in the response.text stringThe full text generated by the model.

{
  "event_id": "event_B1lIeE2Nac33zn5V7h2mm",
  "type": "response.text.done",
  "response_id": "resp_B1lIdtjF4Noqpn5NOjznj",
  "item_id": "item_B1lIdJsAJlJiFs8ztWpJt",
  "output_index": 0,
  "content_index": 0,
  "text": "How can I assist you today?"
}

response.audio.delta

Returned when the output modality includes audio and the model generates new audio data incrementally.

event_idstringA unique identifier for this event.typestringThe event type. This value is always response.audio.delta.response_idstringThe response ID.item_idstringThe message item ID.output_indexintegerThe index of the output item in the response.content_indexintegerThe index of the output item in the response.delta stringIncremental audio data, Base64-encoded.

{
  "event_id": "event_B1osWMZBtrEQbiIwW0qHQ",
  "type": "response.audio.delta",
  "response_id": "resp_P79OOMs8LnrXVpiIHUCKR",
  "item_id": "item_OFaPGtzfWCPyGzxnuEX9i",
  "output_index": 0,
  "content_index": 0,
  "delta": "{base64 audio}"
}

response.audio.done

Returned when the output modality includes audio and the model finishes generating audio data.

Also returned if the response is interrupted, incomplete, or canceled.

event_idstringA unique identifier for this event.typestringThe event type. This value is always response.audio.done.response_idstringThe response ID.item_idstringThe message item ID.output_indexintegerThe index of the output item in the response.content_indexintegerThe index of the output item in the response.

{
    "event_id": "event_Le1TDl7VfyHQxl47DtGxI",
    "type": "response.audio.done",
    "response_id": "resp_HaVOPdbmX6vifiV5pAfJY",
    "item_id": "item_Ls6MtCUWO7LM4E59QziNv",
    "output_index": 0,
    "content_index": 0
}

response.audio_transcript.delta

Returned when the output modality includes audio and the model generates new response.audio_transcript.delta transcript text incrementally.

event_idstringA unique identifier for this event.typestringThe event type. This value is always response.audio_transcript.delta.response_idstringThe response ID.item_idstringThe message item ID.output_indexintegerThe index of the output item in the response.content_indexintegerThe index of the output item in the response.deltastringThe incremental text.

{
    "event_id": "event_BksW7fOwnyavZdDxIzZYM",
    "type": "response.audio_transcript.delta",
    "response_id": "resp_HaVOPdbmX6vifiV5pAfJY",
    "item_id": "item_Ls6MtCUWO7LM4E59QziNv",
    "output_index": 0,
    "content_index": 0,
    "delta": "What"
}

response.audio_transcript.done

Returned as a response.audio_transcript.done event when the output modality includes audio and the model completes the audio transcript.

event_idstringA unique identifier for this event.typestringThe event type. This value is always response.audio_transcript.done.response_idstringThe response ID.item_idstringThe message item ID.output_indexintegerThe index of the output item in the response.content_indexintegerThe index of the output item in the response.transcriptstringThe full transcription text.

{
    "event_id": "event_X49tL2WerT4WjxcmH16lS",
    "type": "response.audio_transcript.done",
    "response_id": "resp_HaVOPdbmX6vifiV5pAfJY",
    "item_id": "item_Ls6MtCUWO7LM4E59QziNv",
    "output_index": 0,
    "content_index": 0,
    "transcript": "Hello! How can I help you?"
}

response.function_call_arguments.delta

Returned as the model streams function call arguments. Concatenate the delta fields in order to build the argument string. The complete content is provided in the subsequent response.function_call_arguments.done event.

event_idstringA unique identifier for this event.typestringThe event type. This value is always response.function_call_arguments.delta.response_idstringThe response ID.item_idstringThe message item ID.output_indexintegerThe index of the output item in the response.call_idstringThe unique ID for this function invocation. This is consistent with the done event in the same turn.deltastringNew segment of the argument string. Concatenate segments in order.

{
    "event_id": "event_SlKoJyEbPEqLq14DSM1u5",
    "type": "response.function_call_arguments.delta",
    "response_id": "resp_JnTOsWXlFhKcFohZbtfz6",
    "item_id": "item_Rhcms7CauTNsQprV5S4Hr",
    "output_index": 0,
    "call_id": "call_2be200f4cafe419b9530dd",
    "delta": " {\"location\": \"Beijing\"}"
}

response.function_call_arguments.done

Indicates that function call arguments are fully generated. The arguments field contains the complete argument string. Use the arguments from this event — not the concatenated delta results — to parse and call the local function.

event_idstringA unique identifier for this event.typestringThe event type. This value is always response.function_call_arguments.done.response_idstringThe response ID.item_idstringThe message item ID.output_indexintegerThe index of the output item in the response.call_idstringThe unique ID for this function invocation.namestringThe name of the function that was called.argumentsstringComplete function call arguments as a JSON string.

{
    "event_id": "event_X6suLyuL5agdH7r6koesM",
    "type": "response.function_call_arguments.done",
    "response_id": "resp_JnTOsWXlFhKcFohZbtfz6",
    "item_id": "item_Rhcms7CauTNsQprV5S4Hr",
    "output_index": 0,
    "name": "get_current_weather",
    "call_id": "call_2be200f4cafe419b9530dd",
    "arguments": " {\"location\": \"Beijing\"}"
}

response.output_item.added

Returned when a new item is created during response generation. The item type can be message or function_call; Qwen3.8-Omni-Flash-Realtime also supports mcp_call; see MCP item examples.

event_idstringA unique identifier for this event.typestringThe event type. This value is always response.output_item.added.response_idstringThe response ID.output_indexintegerThe index of the output item in the response.itemobjectInformation about the output item.

Properties

idstringThe unique ID of the output item.objectstringFor message and function_call items, this field is realtime.item. For MCP items, it has the same value when returned.statusstringThe status of the output item.rolestringPresent only on message items; identifies the message role.contentarrayThe content of the message, returned when the type is message. The array is initially empty in this example; see the completed item in the response.output_item.done example.typestringThe type of the output item. Values include message and function_call. Qwen3.8-Omni-Flash-Realtime also supports mcp_call; see MCP item examples.namestringThe name of the function to call when the type is function_call.call_idstringThe unique ID of the current function invocation when the type is function_call.argumentsstringFunction call arguments as a JSON string when the type is function_call. Initially an empty string in added events.

type=mcp_call (initial item)

objectstring (required)Must be realtime.item.statusstring (required)Initially in_progress.server_labelstring (required)Identifies the MCP server executing the tool.namestring (required)Original tool name.call_idstring (required)Unique ID of this call.argumentsstring (required)Usually empty initially; use response.mcp_call_arguments.done and the final item for full arguments.

{
    "event_id": "event_DsCO341DEVtiATtCB6BUY",
    "type": "response.output_item.added",
    "response_id": "resp_HaVOPdbmX6vifiV5pAfJY",
    "output_index": 0,
    "item": {
        "id": "item_Ls6MtCUWO7LM4E59QziNv",
        "object": "realtime.item",
        "type": "message",
        "status": "in_progress",
        "role": "assistant",
        "content": []
    }
}
// Tool calling scenario
{
    "event_id": "event_HXmKt5pGoiRtXx7Hq7zpN",
    "type": "response.output_item.added",
    "response_id": "resp_TucN5QgymL5MA8vkJvFlS",
    "output_index": 0,
    "item": {
        "id": "item_FEG9qJGNkPcdf4et3p7BV",
        "object": "realtime.item",
        "type": "function_call",
        "status": "in_progress",
        "call_id": "call_bc0a7fb7235840f69ecfe4",
        "name": "get_current_weather",
        "arguments": ""
    }
}

response.output_item.done

Returned when an output item is fully generated.

event_idstringA unique identifier for this event.typestringThe event type. This value is always response.output_item.done.response_idstringThe response ID.output_indexintegerThe index of the output item in the response.itemobjectThe output item information.

Properties

Array item

typestringThe content-part type; audio in this example.textstringText content in this example.

typestringThe type of the output item. Values include message and function_call. Qwen3.8-Omni-Flash-Realtime also supports mcp_call; see MCP item examples.namestringThe name of the function that is called when the type is function_call.call_idstringWhen the type is function_call, this is the unique ID for the function invocation.argumentsstringWhen the type is function_call, contains the full function call arguments as a JSON string.

type=mcp_call (final item)

Properties

typestring (required)Must be tool_execution_error.messagestring (required)A client-safe description without sensitive upstream response content.

If the MCP server returns isError=true, the final status is failed and the original output may also be present.

{
    "event_id": "event_MEu5nlLw1LsOguHiehIP8",
    "type": "response.output_item.done",
    "response_id": "resp_HaVOPdbmX6vifiV5pAfJY",
    "output_index": 0,
    "item": {
        "id": "item_Ls6MtCUWO7LM4E59QziNv",
        "object": "realtime.item",
        "type": "message",
        "status": "completed",
        "role": "assistant",
        "content": [
            {
                "type": "audio",
                "text": "Hello! How can I help you?"
            }
        ]
    }
}
// Tool calling scenario
{
    "event_id": "event_FHspdfAnCyjuME3mmAwSY",
    "type": "response.output_item.done",
    "response_id": "resp_TucN5QgymL5MA8vkJvFlS",
    "output_index": 0,
    "item": {
        "id": "item_FEG9qJGNkPcdf4et3p7BV",
        "object": "realtime.item",
        "type": "function_call",
        "status": "completed",
        "call_id": "call_bc0a7fb7235840f69ecfe4",
        "name": "get_current_weather",
        "arguments": " {\"location\": \"Hangzhou\"}"
    }
}

response.content_part.added

Returned when a new content part is added to an assistant message item during response generation.

event_idstringA unique identifier for this event.typestringThe event type. This value is always response.content_part.added.response_idstringThe response ID.item_idstringThe message item ID.output_indexintegerThe index of the output item in the response. This value is always 0.content_indexintegerThe index of the internal part within the output item. This value is always 0.partobjectThe output item information.

Properties

typestringThe type of the content part.textstringThe text of the content part.

{
    "event_id": "event_AVBOmrgY3C8bjlRajfSUT",
    "type": "response.content_part.added",
    "response_id": "resp_HaVOPdbmX6vifiV5pAfJY",
    "item_id": "item_Ls6MtCUWO7LM4E59QziNv",
    "output_index": 0,
    "content_index": 0,
    "part": {
        "type": "audio",
        "text": ""
    }
}

response.content_part.done

Returned when streaming of a content part within an assistant message item finishes.

event_idstringA unique identifier for this event.typestringThe event type. This value is always response.content_part.done.response_idstringThe response ID.item_idstringThe message item ID.output_indexintegerThe index of the output item in the response. This value is always 0.content_indexintegerThe index of the content part in the content array. This value is always 0.partobjectThe output item information.

Properties

typestringThe type of the content part.textstringThe text of the content part.

{
    "event_id": "event_Il8HD19v58Qr5IBkw7LtN",
    "type": "response.content_part.done",
    "response_id": "resp_HaVOPdbmX6vifiV5pAfJY",
    "item_id": "item_Ls6MtCUWO7LM4E59QziNv",
    "output_index": 0,
    "content_index": 0,
    "part": {
        "type": "audio",
        "text": "Hello! How can I help you?"
    }
}

MCP events

This section describes WebSocket events and fields for qwen3.8-omni-flash-realtime. Other base events and fields use the common protocol documented above. Required fields are required when their containing object is present. IDs are opaque strings; do not rely on their lengths, prefixes, or generation rules. arguments and output are strings whose contents require JSON parsing. MCP connections, discovery, and calls are subject to service quotas and timeouts.

mcp_list_tools.*

Event type	When emitted
`mcp_list_tools.in_progress`	Tool discovery starts for an MCP server.
`mcp_list_tools.completed`	Discovery succeeds and `allowed_tools` filtering completes.
`mcp_list_tools.failed`	Discovery fails, times out, or exceeds service limits.

All three require string fields event_id (unique event ID), type (event type above), and item_id (associated mcp_list_tools item). in_progress can arrive before session.updated. For completed and failed, conversation.item.created containing the final tool list or error arrives first, followed by the status event with the same item_id.

{
  "event_id": "opaque_event_id",
  "type": "mcp_list_tools.completed",
  "item_id": "opaque_item_id"
}

response.mcp_call_arguments.delta

Field	Type	Required	Meaning
`event_id`	string	Yes	Unique event ID.
`type`	string	Yes	`response.mcp_call_arguments.delta`
`response_id`	string	Yes	Parent Response ID.
`item_id`	string	Yes	Current `mcp_call` item ID.
`output_index`	integer	Yes	Zero-based index in the parent Response output array.
`delta`	string	Yes	Incremental JSON-string fragment; concatenate in event order.
`obfuscation`	string	No	Optional obfuscation string; ignore when assembling and parsing arguments.

{
  "event_id": "opaque_event_id",
  "type": "response.mcp_call_arguments.delta",
  "response_id": "opaque_response_id",
  "item_id": "opaque_item_id",
  "output_index": 0,
  "delta": "{\"city\":\"杭",
  "obfuscation": "opaque-value"
}

response.mcp_call_arguments.done

Requires event_id, type, response_id, and item_id (strings), output_index (integer, same meaning as above), and arguments (string). type is response.mcp_call_arguments.done. arguments contains the complete JSON-encoded arguments and is authoritative.

{
  "event_id": "opaque_event_id",
  "type": "response.mcp_call_arguments.done",
  "response_id": "opaque_response_id",
  "item_id": "opaque_item_id",
  "output_index": 0,
  "arguments": "{\"city\":\"杭州\"}"
}

response.mcp_call.*

Event type	When emitted
`response.mcp_call.in_progress`	Arguments are complete and approval has been granted or is unnecessary; the MCP call starts.
`response.mcp_call.completed`	The MCP call succeeds.
`response.mcp_call.failed`	Connection, protocol, or tool business error; approval rejection or timeout; call timeout; or cancellation.

All three require event_id, type, and item_id (strings), and output_index (integer). item_id identifies the current mcp_call; output_index is its index in the parent Response output array.

{
  "event_id": "opaque_event_id",
  "type": "response.mcp_call.in_progress",
  "item_id": "opaque_item_id",
  "output_index": 0
}

MCP conversation items

These objects are types of the item field in events, applicable to Qwen3.8-Omni-Flash-Realtime.

mcp_list_tools item

Returned as conversation.item.created.item; see the type=mcp_list_tools branch under conversation.item.created for its fields. Example:

{
  "event_id": "opaque_event_id",
  "type": "conversation.item.created",
  "item": {
    "id": "opaque_item_id",
    "type": "mcp_list_tools",
    "server_label": "amap",
    "tools": [
      {
        "name": "maps_weather",
        "description": "查询天气",
        "input_schema": {
          "type": "object",
          "properties": {
            "city": {
              "type": "string",
              "description": "城市名"
            }
          },
          "required": ["city"]
        }
      }
    ]
  }
}

Initial mcp_call item

When the model selects an MCP tool, this item appears in response.output_item.added.item and may also appear in conversation.item.created.item; see the corresponding item branches under response.output_item.added and conversation.item.created. response.output_item.added example:

{
  "event_id": "opaque_event_id",
  "type": "response.output_item.added",
  "response_id": "opaque_response_id",
  "output_index": 0,
  "item": {
    "id": "opaque_item_id",
    "object": "realtime.item",
    "type": "mcp_call",
    "status": "in_progress",
    "call_id": "opaque_call_id",
    "server_label": "amap",
    "name": "maps_weather",
    "arguments": ""
  }
}

mcp_approval_request item

Returned in conversation.item.created; see conversation.item.created for the event and approval item fields. Example:

{
  "event_id": "opaque_event_id",
  "type": "conversation.item.created",
  "response_id": "opaque_response_id",
  "item_id": "opaque_approval_id",
  "previous_item_id": "opaque_item_id",
  "item": {
    "id": "opaque_approval_id",
    "type": "mcp_approval_request",
    "server_label": "amap",
    "name": "maps_weather",
    "arguments": "{\"city\":\"杭州\"}",
    "call_id": "opaque_call_id"
  }
}

Final mcp_call item

After a call reaches a terminal state, the item appears in response.output_item.done.item and in the final parent response.done.response.output snapshot; see the corresponding branches under response.output_item.done and response.done. Successful call:

{
  "event_id": "opaque_event_id",
  "type": "response.output_item.done",
  "response_id": "opaque_response_id",
  "output_index": 0,
  "item": {
    "id": "opaque_item_id",
    "type": "mcp_call",
    "status": "completed",
    "call_id": "opaque_call_id",
    "server_label": "amap",
    "name": "maps_weather",
    "arguments": "{\"city\":\"杭州\"}",
    "output": "{\"content\":[{\"type\":\"text\",\"text\":\"...\"}],\"isError\":false}"
  }
}

Failed call:

{
  "event_id": "opaque_event_id",
  "type": "response.output_item.done",
  "response_id": "opaque_response_id",
  "output_index": 0,
  "item": {
    "id": "opaque_item_id",
    "type": "mcp_call",
    "status": "failed",
    "call_id": "opaque_call_id",
    "server_label": "amap",
    "name": "maps_weather",
    "arguments": "{\"city\":\"杭州\"}",
    "error": {
      "type": "tool_execution_error",
      "message": "MCP tool call failed (call_timeout)."
    }
  }
}

MCP errors

MCP errors can occur during tool discovery or tool execution. For discovery errors, see error under the mcp_list_tools branch of conversation.item.created; for execution errors, see the mcp_call branch of response.output_item.done.

See Qwen-Omni-Realtime.

​error

​session.created

​session.updated

​input_audio_buffer.speech_started

​input_audio_buffer.speech_stopped

​input_audio_buffer.committed

​input_audio_buffer.cleared

​conversation.item.created

​conversation.item.input_audio_transcription.delta

​conversation.item.input_audio_transcription.completed

​conversation.item.input_audio_transcription.failed

​response.created

​response.done

​response.text.delta

​response.text.done

​response.audio.delta

​response.audio.done

​response.audio_transcript.delta

​response.audio_transcript.done

​response.function_call_arguments.delta

​response.function_call_arguments.done

​response.output_item.added

​response.output_item.done

​response.content_part.added

​response.content_part.done

​MCP events

​mcp_list_tools.*

​response.mcp_call_arguments.delta

​response.mcp_call_arguments.done

​response.mcp_call.*

​MCP conversation items

​mcp_list_tools item

​Initial mcp_call item

​mcp_approval_request item

​Final mcp_call item

​MCP errors

error

session.created

session.updated

input_audio_buffer.speech_started

input_audio_buffer.speech_stopped

input_audio_buffer.committed

input_audio_buffer.cleared

conversation.item.created

conversation.item.input_audio_transcription.delta

conversation.item.input_audio_transcription.completed

conversation.item.input_audio_transcription.failed

response.created

response.done

response.text.delta

response.text.done

response.audio.delta

response.audio.done

response.audio_transcript.delta

response.audio_transcript.done

response.function_call_arguments.delta

response.function_call_arguments.done

response.output_item.added

response.output_item.done

response.content_part.added

response.content_part.done

MCP events

mcp_list_tools.*

response.mcp_call_arguments.delta

response.mcp_call_arguments.done

response.mcp_call.*

MCP conversation items

mcp_list_tools item

Initial mcp_call item

mcp_approval_request item

Final mcp_call item

MCP errors