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vllm.entrypoints.openai.responses.protocol

ResponseRawMessageAndToken

Bases: OpenAIBaseModel

Class to show the raw message. If message / tokens diverge, tokens is the source of truth

Source code in vllm/entrypoints/openai/responses/protocol.py
class ResponseRawMessageAndToken(OpenAIBaseModel):
    """Class to show the raw message.
    If message / tokens diverge, tokens is the source of truth"""

    message: str
    tokens: list[int]
    type: Literal["raw_message_tokens"] = "raw_message_tokens"

ResponseReasoningPartAddedEvent

Bases: OpenAIBaseModel

Source code in vllm/entrypoints/openai/responses/protocol.py
class ResponseReasoningPartAddedEvent(OpenAIBaseModel):
    content_index: int
    """The index of the content part that is done."""

    item_id: str
    """The ID of the output item that the content part was added to."""

    output_index: int
    """The index of the output item that the content part was added to."""

    part: ResponseReasoningTextContent
    """The content part that is done."""

    sequence_number: int
    """The sequence number of this event."""

    type: Literal["response.reasoning_part.added"]
    """The type of the event. Always `response.reasoning_part.added`."""

content_index instance-attribute

content_index: int

The index of the content part that is done.

item_id instance-attribute

item_id: str

The ID of the output item that the content part was added to.

output_index instance-attribute

output_index: int

The index of the output item that the content part was added to.

part instance-attribute

part: Content

The content part that is done.

sequence_number instance-attribute

sequence_number: int

The sequence number of this event.

type instance-attribute

type: Literal['response.reasoning_part.added']

The type of the event. Always response.reasoning_part.added.

ResponseReasoningPartDoneEvent

Bases: OpenAIBaseModel

Source code in vllm/entrypoints/openai/responses/protocol.py
class ResponseReasoningPartDoneEvent(OpenAIBaseModel):
    content_index: int
    """The index of the content part that is done."""

    item_id: str
    """The ID of the output item that the content part was added to."""

    output_index: int
    """The index of the output item that the content part was added to."""

    part: ResponseReasoningTextContent
    """The content part that is done."""

    sequence_number: int
    """The sequence number of this event."""

    type: Literal["response.reasoning_part.done"]
    """The type of the event. Always `response.reasoning_part.done`."""

content_index instance-attribute

content_index: int

The index of the content part that is done.

item_id instance-attribute

item_id: str

The ID of the output item that the content part was added to.

output_index instance-attribute

output_index: int

The index of the output item that the content part was added to.

part instance-attribute

part: Content

The content part that is done.

sequence_number instance-attribute

sequence_number: int

The sequence number of this event.

type instance-attribute

type: Literal['response.reasoning_part.done']

The type of the event. Always response.reasoning_part.done.

ResponsesRequest

Bases: OpenAIBaseModel

Source code in vllm/entrypoints/openai/responses/protocol.py
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class ResponsesRequest(OpenAIBaseModel):
    # Ordered by official OpenAI API documentation
    # https://platform.openai.com/docs/api-reference/responses/create
    background: bool | None = False
    include: (
        list[
            Literal[
                "code_interpreter_call.outputs",
                "computer_call_output.output.image_url",
                "file_search_call.results",
                "message.input_image.image_url",
                "message.output_text.logprobs",
                "reasoning.encrypted_content",
            ],
        ]
        | None
    ) = None
    input: str | list[ResponseInputOutputItem]
    instructions: str | None = None
    max_output_tokens: int | None = None
    max_tool_calls: int | None = None
    metadata: Metadata | None = None
    model: str | None = None
    logit_bias: dict[str, float] | None = None
    parallel_tool_calls: bool | None = True
    previous_response_id: str | None = None
    prompt: ResponsePrompt | None = None
    reasoning: Reasoning | None = None
    service_tier: Literal["auto", "default", "flex", "scale", "priority"] = "auto"
    store: bool | None = True
    stream: bool | None = False
    temperature: float | None = None
    text: ResponseTextConfig | None = None
    tool_choice: ToolChoice = "auto"
    tools: list[Tool] = Field(default_factory=list)
    top_logprobs: int | None = 0
    top_p: float | None = None
    top_k: int | None = None
    truncation: Literal["auto", "disabled"] | None = "disabled"
    user: str | None = None
    skip_special_tokens: bool = True
    include_stop_str_in_output: bool = False
    presence_penalty: float | None = Field(
        default=None,
        ge=-2.0,
        le=2.0,
        description=(
            "The presence penalty that was used to penalize new tokens based on "
            "whether they appear in the text so far."
        ),
    )
    frequency_penalty: float | None = Field(
        default=None,
        ge=-2.0,
        le=2.0,
        description=(
            "The frequency penalty that was used to penalize new tokens based on "
            "their frequency in the text so far."
        ),
    )
    prompt_cache_key: str | None = Field(
        default=None,
        description=(
            "A key that was used to read from or write to the prompt cache."
            "Note: This field has not been implemented yet "
            "and vLLM will ignore it."
        ),
    )

    # --8<-- [start:responses-extra-params]
    request_id: str = Field(
        default_factory=lambda: f"resp_{random_uuid()}",
        description=(
            "The request_id related to this request. If the caller does "
            "not set it, a random_uuid will be generated. This id is used "
            "through out the inference process and return in response."
        ),
    )
    media_io_kwargs: dict[str, dict[str, Any]] | None = Field(
        default=None,
        description=(
            "Additional kwargs to pass to the media IO connectors, "
            "keyed by modality. Merged with engine-level media_io_kwargs."
        ),
    )
    mm_processor_kwargs: dict[str, Any] | None = Field(
        default=None,
        description=("Additional kwargs to pass to the HF processor."),
    )
    priority: int = Field(
        default=0,
        ge=_INT64_MIN,
        le=_INT64_MAX,
        description=(
            "The priority of the request (lower means earlier handling; "
            "default: 0). Any priority other than 0 will raise an error "
            "if the served model does not use priority scheduling."
        ),
    )
    cache_salt: str | None = Field(
        default=None,
        description=(
            "If specified, the prefix cache will be salted with the provided "
            "string to prevent an attacker to guess prompts in multi-user "
            "environments. The salt should be random, protected from "
            "access by 3rd parties, and long enough to be "
            "unpredictable (e.g., 43 characters base64-encoded, corresponding "
            "to 256 bit)."
        ),
    )

    enable_response_messages: bool = Field(
        default=False,
        description=(
            "Dictates whether or not to return messages as part of the "
            "response object. Currently only supported for non-background."
        ),
    )
    # similar to input_messages / output_messages in ResponsesResponse
    # we take in previous_input_messages (ie in harmony format)
    # this cannot be used in conjunction with previous_response_id
    # TODO: consider supporting non harmony messages as well
    previous_input_messages: list[OpenAIHarmonyMessage | dict] | None = None
    structured_outputs: StructuredOutputsParams | None = Field(
        default=None,
        description="Additional kwargs for structured outputs",
    )

    repetition_penalty: float | None = None
    seed: int | None = Field(None, ge=_INT64_MIN, le=_INT64_MAX)
    stop: str | list[str] | None = []
    ignore_eos: bool = False
    vllm_xargs: dict[str, str | int | float | list[str | int | float]] | None = Field(
        default=None,
        description=(
            "Additional request parameters with (list of) string or "
            "numeric values, used by custom extensions."
        ),
    )
    kv_transfer_params: dict[str, Any] | None = Field(
        default=None,
        description="KVTransfer parameters used for disaggregated serving.",
    )
    # --8<-- [end:responses-extra-params]

    def build_chat_params(
        self,
        default_template: str | None,
        default_template_content_format: ChatTemplateContentFormatOption,
    ) -> ChatParams:
        from .utils import should_continue_final_message

        # Check if we should continue the final message (partial completion)
        # This enables Anthropic-style partial message completion where the
        # user provides an incomplete assistant message to continue from.
        continue_final = should_continue_final_message(self.input)

        reasoning = self.reasoning

        return ChatParams(
            chat_template=default_template,
            chat_template_content_format=default_template_content_format,
            chat_template_kwargs=merge_kwargs(  # To remove unset values
                {},
                dict(
                    add_generation_prompt=not continue_final,
                    continue_final_message=continue_final,
                    reasoning_effort=None if reasoning is None else reasoning.effort,
                ),
            ),
            media_io_kwargs=self.media_io_kwargs,
        )

    def build_tok_params(self, model_config: ModelConfig) -> TokenizeParams:
        return TokenizeParams(
            max_total_tokens=model_config.max_model_len,
            max_output_tokens=self.max_output_tokens or 0,
            truncate_prompt_tokens=-1 if self.truncation != "disabled" else None,
            max_total_tokens_param="max_model_len",
            max_output_tokens_param="max_output_tokens",
        )

    _DEFAULT_SAMPLING_PARAMS = {
        "temperature": 1.0,
        "top_p": 1.0,
        "top_k": 0,
    }

    def to_sampling_params(
        self,
        default_max_tokens: int,
        default_sampling_params: dict | None = None,
    ) -> SamplingParams:
        if self.max_output_tokens is None:
            max_tokens = default_max_tokens
        else:
            max_tokens = min(self.max_output_tokens, default_max_tokens)

        default_sampling_params = default_sampling_params or {}
        if (temperature := self.temperature) is None:
            temperature = default_sampling_params.get(
                "temperature", self._DEFAULT_SAMPLING_PARAMS["temperature"]
            )
        if (top_p := self.top_p) is None:
            top_p = default_sampling_params.get(
                "top_p", self._DEFAULT_SAMPLING_PARAMS["top_p"]
            )
        if (top_k := self.top_k) is None:
            top_k = default_sampling_params.get(
                "top_k", self._DEFAULT_SAMPLING_PARAMS["top_k"]
            )

        if (repetition_penalty := self.repetition_penalty) is None:
            repetition_penalty = default_sampling_params.get("repetition_penalty", 1.0)

        if (presence_penalty := self.presence_penalty) is None:
            presence_penalty = default_sampling_params.get("presence_penalty", 0.0)

        if (frequency_penalty := self.frequency_penalty) is None:
            frequency_penalty = default_sampling_params.get("frequency_penalty", 0.0)

        stop_token_ids = default_sampling_params.get("stop_token_ids")

        # Structured output
        structured_outputs = self.structured_outputs

        # Also check text.format for OpenAI-style json_schema
        if self.text is not None and self.text.format is not None:
            if structured_outputs is not None:
                raise VLLMValidationError(
                    "Cannot specify both structured_outputs and text.format",
                    parameter="structured_outputs",
                )
            response_format = self.text.format
            if (
                response_format.type == "json_schema"
                and response_format.schema_ is not None
            ):
                structured_outputs = StructuredOutputsParams(
                    json=response_format.schema_  # type: ignore[call-arg]
                    # --follow-imports skip hides the class definition but also hides
                    # multiple third party conflicts, so best of both evils
                )

        stop = self.stop if self.stop else []
        if isinstance(stop, str):
            stop = [stop]

        extra_args: dict[str, Any] = self.vllm_xargs if self.vllm_xargs else {}
        if self.kv_transfer_params:
            extra_args["kv_transfer_params"] = self.kv_transfer_params

        return SamplingParams.from_optional(
            temperature=temperature,
            top_p=top_p,
            top_k=top_k,
            max_tokens=max_tokens,
            logprobs=self.top_logprobs if self.is_include_output_logprobs() else None,
            stop_token_ids=stop_token_ids,
            stop=stop,
            frequency_penalty=frequency_penalty,
            presence_penalty=presence_penalty,
            repetition_penalty=repetition_penalty,
            seed=self.seed,
            ignore_eos=self.ignore_eos,
            output_kind=(
                RequestOutputKind.DELTA if self.stream else RequestOutputKind.FINAL_ONLY
            ),
            structured_outputs=structured_outputs,
            logit_bias=self.logit_bias,
            extra_args=extra_args,
            skip_clone=True,  # Created fresh per request, safe to skip clone
            skip_special_tokens=self.skip_special_tokens,
            include_stop_str_in_output=self.include_stop_str_in_output,
        )

    def is_include_output_logprobs(self) -> bool:
        """Check if the request includes output logprobs."""
        if self.include is None:
            return False
        return (
            isinstance(self.include, list)
            and "message.output_text.logprobs" in self.include
        )

    @model_validator(mode="before")
    @classmethod
    def validate_background(cls, data):
        if not data.get("background"):
            return data
        if not data.get("store", True):
            raise VLLMValidationError(
                "background can only be used when `store` is true",
                parameter="background",
            )
        return data

    @model_validator(mode="before")
    @classmethod
    def validate_prompt(cls, data):
        if data.get("prompt") is not None:
            raise VLLMValidationError(
                "prompt template is not supported", parameter="prompt"
            )
        return data

    @model_validator(mode="before")
    @classmethod
    def check_cache_salt_support(cls, data):
        if data.get("cache_salt") is not None and (
            not isinstance(data["cache_salt"], str) or not data["cache_salt"]
        ):
            raise VLLMValidationError(
                "Parameter 'cache_salt' must be a non-empty string if provided.",
                parameter="cache_salt",
            )
        return data

    @model_validator(mode="before")
    @classmethod
    def function_call_parsing(cls, data):
        """Parse function_call dictionaries into ResponseFunctionToolCall objects.
        This ensures Pydantic can properly resolve union types in the input field.
        Function calls provided as dicts are converted to ResponseFunctionToolCall
        objects before validation, while invalid structures are left for Pydantic
        to reject with appropriate error messages.
        """

        input_data = data.get("input")

        # Early return for None, strings, or bytes
        # (strings are iterable but shouldn't be processed)
        if input_data is None or isinstance(input_data, (str, bytes)):
            return data

        # Convert iterators (like ValidatorIterator) to list
        if not isinstance(input_data, list):
            try:
                input_data = list(input_data)
            except TypeError:
                # Not iterable, leave as-is for Pydantic to handle
                return data

        processed_input = []
        for item in input_data:
            if isinstance(item, dict) and item.get("type") == "function_call":
                try:
                    processed_input.append(ResponseFunctionToolCall(**item))
                except ValidationError:
                    # Let Pydantic handle validation for malformed function calls
                    logger.debug(
                        "Failed to parse function_call to ResponseFunctionToolCall, "
                        "leaving for Pydantic validation"
                    )
                    processed_input.append(item)
            else:
                processed_input.append(item)

        data["input"] = processed_input
        return data

    @model_validator(mode="before")
    @classmethod
    def check_tool_usage(cls, data):
        if not isinstance(data, dict):
            return data

        tools = data.get("tools")
        tool_choice = data.get("tool_choice", "auto")
        has_tools = tools is not None and len(tools) > 0
        is_named_tool_choice = (
            isinstance(tool_choice, dict) and tool_choice.get("type") == "function"
        )

        if not has_tools:
            if tool_choice in ("auto", "none"):
                data["tool_choice"] = "none"
            elif tool_choice == "required":
                raise VLLMValidationError(
                    "Tool choice 'required' must be specified with 'tools' parameter.",
                    parameter="tool_choice",
                )
            elif is_named_tool_choice:
                raise VLLMValidationError(
                    "Tool choice 'function' not found in 'tools' parameter.",
                    parameter="tool_choice",
                )
        elif is_named_tool_choice and tools is not None:
            tool_name = tool_choice.get("name")
            tool_names = {
                t.get("name") if isinstance(t, dict) else getattr(t, "name", None)
                for t in tools
            }
            if not tool_name or tool_name not in tool_names:
                raise VLLMValidationError(
                    "Tool choice 'function' not found in 'tools' parameter.",
                    parameter="tool_choice",
                )

        return data

function_call_parsing classmethod

function_call_parsing(data)

Parse function_call dictionaries into ResponseFunctionToolCall objects. This ensures Pydantic can properly resolve union types in the input field. Function calls provided as dicts are converted to ResponseFunctionToolCall objects before validation, while invalid structures are left for Pydantic to reject with appropriate error messages.

Source code in vllm/entrypoints/openai/responses/protocol.py
@model_validator(mode="before")
@classmethod
def function_call_parsing(cls, data):
    """Parse function_call dictionaries into ResponseFunctionToolCall objects.
    This ensures Pydantic can properly resolve union types in the input field.
    Function calls provided as dicts are converted to ResponseFunctionToolCall
    objects before validation, while invalid structures are left for Pydantic
    to reject with appropriate error messages.
    """

    input_data = data.get("input")

    # Early return for None, strings, or bytes
    # (strings are iterable but shouldn't be processed)
    if input_data is None or isinstance(input_data, (str, bytes)):
        return data

    # Convert iterators (like ValidatorIterator) to list
    if not isinstance(input_data, list):
        try:
            input_data = list(input_data)
        except TypeError:
            # Not iterable, leave as-is for Pydantic to handle
            return data

    processed_input = []
    for item in input_data:
        if isinstance(item, dict) and item.get("type") == "function_call":
            try:
                processed_input.append(ResponseFunctionToolCall(**item))
            except ValidationError:
                # Let Pydantic handle validation for malformed function calls
                logger.debug(
                    "Failed to parse function_call to ResponseFunctionToolCall, "
                    "leaving for Pydantic validation"
                )
                processed_input.append(item)
        else:
            processed_input.append(item)

    data["input"] = processed_input
    return data

is_include_output_logprobs

is_include_output_logprobs() -> bool

Check if the request includes output logprobs.

Source code in vllm/entrypoints/openai/responses/protocol.py
def is_include_output_logprobs(self) -> bool:
    """Check if the request includes output logprobs."""
    if self.include is None:
        return False
    return (
        isinstance(self.include, list)
        and "message.output_text.logprobs" in self.include
    )

serialize_message

serialize_message(msg)

Serializes a single message

Source code in vllm/entrypoints/openai/responses/protocol.py
def serialize_message(msg):
    """
    Serializes a single message
    """
    if isinstance(msg, dict):
        return msg
    elif hasattr(msg, "to_dict"):
        return msg.to_dict()
    else:
        # fallback to pydantic dump
        return msg.model_dump(mode="json", by_alias=True)

serialize_messages

serialize_messages(msgs)

Serializes multiple messages

Source code in vllm/entrypoints/openai/responses/protocol.py
def serialize_messages(msgs):
    """
    Serializes multiple messages
    """
    return [serialize_message(msg) for msg in msgs] if msgs else None