letta-server/letta/interfaces/openai_streaming_interface.py

import asyncio
from collections.abc import AsyncGenerator
from datetime import datetime, timezone
from typing import Optional

from openai import AsyncStream
from openai.types.chat.chat_completion_chunk import ChatCompletionChunk
from openai.types.responses import (
    ParsedResponse,
    ResponseCompletedEvent,
    ResponseContentPartAddedEvent,
    ResponseContentPartDoneEvent,
    ResponseCreatedEvent,
    ResponseFunctionCallArgumentsDeltaEvent,
    ResponseFunctionCallArgumentsDoneEvent,
    ResponseFunctionToolCall,
    ResponseInProgressEvent,
    ResponseOutputItemAddedEvent,
    ResponseOutputItemDoneEvent,
    ResponseOutputMessage,
    ResponseOutputText,
    ResponseReasoningItem,
    ResponseReasoningSummaryPartAddedEvent,
    ResponseReasoningSummaryPartDoneEvent,
    ResponseReasoningSummaryTextDeltaEvent,
    ResponseReasoningSummaryTextDoneEvent,
    ResponseTextDeltaEvent,
    ResponseTextDoneEvent,
)
from openai.types.responses.response_stream_event import ResponseStreamEvent

from letta.constants import DEFAULT_MESSAGE_TOOL, DEFAULT_MESSAGE_TOOL_KWARG
from letta.llm_api.error_utils import is_context_window_overflow_message
from letta.llm_api.openai_client import is_openai_reasoning_model
from letta.local_llm.utils import num_tokens_from_functions, num_tokens_from_messages
from letta.log import get_logger
from letta.schemas.letta_message import (
    ApprovalRequestMessage,
    AssistantMessage,
    HiddenReasoningMessage,
    LettaMessage,
    ReasoningMessage,
    ToolCallDelta,
    ToolCallMessage,
)
from letta.schemas.letta_message_content import (
    OmittedReasoningContent,
    ReasoningContent,
    SummarizedReasoningContent,
    SummarizedReasoningContentPart,
    TextContent,
)
from letta.schemas.letta_stop_reason import LettaStopReason, StopReasonType
from letta.schemas.message import Message
from letta.schemas.openai.chat_completion_response import FunctionCall, ToolCall
from letta.server.rest_api.json_parser import OptimisticJSONParser
from letta.server.rest_api.streaming_response import RunCancelledException
from letta.server.rest_api.utils import decrement_message_uuid
from letta.services.context_window_calculator.token_counter import create_token_counter
from letta.streaming_utils import (
    FunctionArgumentsStreamHandler,
    JSONInnerThoughtsExtractor,
    sanitize_streamed_message_content,
)

logger = get_logger(__name__)


class OpenAIStreamingInterface:
    """
    Encapsulates the logic for streaming responses from OpenAI.
    This class handles parsing of partial tokens, pre-execution messages,
    and detection of tool call events.
    """

    def __init__(
        self,
        use_assistant_message: bool = False,
        is_openai_proxy: bool = False,
        messages: Optional[list] = None,
        tools: Optional[list] = None,
        put_inner_thoughts_in_kwarg: bool = True,
        requires_approval_tools: list = [],
        run_id: str | None = None,
        step_id: str | None = None,
        cancellation_event: Optional["asyncio.Event"] = None,
    ):
        self.use_assistant_message = use_assistant_message

        # Create token counter for fallback token counting (when API doesn't return usage)
        # Use openai endpoint type for approximate counting in streaming context
        self._fallback_token_counter = create_token_counter(model_endpoint_type="openai")
        self.assistant_message_tool_name = DEFAULT_MESSAGE_TOOL
        self.assistant_message_tool_kwarg = DEFAULT_MESSAGE_TOOL_KWARG
        self.put_inner_thoughts_in_kwarg = put_inner_thoughts_in_kwarg
        self.run_id = run_id
        self.step_id = step_id
        self.cancellation_event = cancellation_event

        self.optimistic_json_parser: OptimisticJSONParser = OptimisticJSONParser()
        self.function_args_reader = JSONInnerThoughtsExtractor(wait_for_first_key=put_inner_thoughts_in_kwarg)
        # Reader that extracts only the assistant message value from send_message args
        self.assistant_message_json_reader = FunctionArgumentsStreamHandler(json_key=self.assistant_message_tool_kwarg)
        # Switch to list-based accumulation to avoid O(n^2) string growth
        self._function_name_parts: list[str] = []
        self._function_args_buffer_parts: list[str] | None = None
        self._function_id_parts: list[str] = []
        self.last_flushed_function_name = None
        self.last_flushed_function_id = None

        # Buffer to hold function arguments until inner thoughts are complete
        self._current_function_arguments_parts: list[str] = []
        self.current_json_parse_result = {}

        # Premake IDs for database writes
        self.letta_message_id = Message.generate_id()

        self.message_id = None
        self.model = None

        # Token counters (from OpenAI usage)
        self.input_tokens = 0
        self.output_tokens = 0

        # Fallback token counters (using tiktoken cl200k-base)
        self.fallback_input_tokens = 0
        self.fallback_output_tokens = 0

        # Store messages and tools for fallback counting
        self.is_openai_proxy = is_openai_proxy
        self.messages = messages or []
        self.tools = tools or []

        self.content_buffer: list[str] = []
        self.tool_call_name: str | None = None
        self.tool_call_id: str | None = None
        self.reasoning_messages = []
        self.emitted_hidden_reasoning = False  # Track if we've emitted hidden reasoning message

        self.requires_approval_tools = requires_approval_tools

        # Diagnostic: track last event for debugging
        self.last_event_type: str | None = None
        self.total_events_received: int = 0
        self.stream_was_cancelled: bool = False

    def get_reasoning_content(self) -> list[TextContent | OmittedReasoningContent]:
        content = "".join(self.reasoning_messages).strip()

        # Right now we assume that all models omit reasoning content for OAI,
        # if this changes, we should return the reasoning content
        if is_openai_reasoning_model(self.model):
            return [OmittedReasoningContent()]
        else:
            return [TextContent(text=content)]

    def _get_function_name_buffer(self) -> str | None:
        return "".join(self._function_name_parts) if self._function_name_parts else None

    def _get_function_id_buffer(self) -> str | None:
        return "".join(self._function_id_parts) if self._function_id_parts else None

    def _get_current_function_id(self) -> str | None:
        """Prefer the last flushed ID when the live buffer is empty.
        Ensures tool_call_id is present on subsequent argument deltas after name/id flush."""
        return self.last_flushed_function_id if self.last_flushed_function_id else self._get_function_id_buffer()

    def _clear_function_buffers(self) -> None:
        self._function_name_parts = []
        self._function_id_parts = []

    def _append_function_name(self, s: str) -> None:
        self._function_name_parts.append(s)

    def _append_function_id(self, s: str) -> None:
        self._function_id_parts.append(s)

    def _append_current_function_arguments(self, s: str) -> None:
        self._current_function_arguments_parts.append(s)

    def _get_current_function_arguments(self) -> str:
        return "".join(self._current_function_arguments_parts)

    def get_tool_call_object(self) -> ToolCall:
        """Useful for agent loop"""
        function_name = self.last_flushed_function_name if self.last_flushed_function_name else self._get_function_name_buffer()
        if not function_name:
            raise ValueError("No tool call ID available")
        tool_call_id = self.last_flushed_function_id if self.last_flushed_function_id else self._get_function_id_buffer()
        if not tool_call_id:
            raise ValueError("No tool call ID available")
        return ToolCall(
            id=tool_call_id,
            function=FunctionCall(arguments=self._get_current_function_arguments(), name=function_name),
        )

    async def process(
        self,
        stream: AsyncStream[ChatCompletionChunk],
        ttft_span: Optional["Span"] = None,
    ) -> AsyncGenerator[LettaMessage | LettaStopReason, None]:
        """
        Iterates over the OpenAI stream, yielding SSE events.
        It also collects tokens and detects if a tool call is triggered.
        """
        # Fallback input token counting - this should only be required for non-OpenAI providers using the OpenAI client (e.g. LMStudio)
        if self.is_openai_proxy:
            if self.messages:
                # Convert messages to dict format for token counting
                message_dicts = [msg.to_openai_dict() if hasattr(msg, "to_openai_dict") else msg for msg in self.messages]
                message_dicts = [m for m in message_dicts if m is not None]
                self.fallback_input_tokens = num_tokens_from_messages(message_dicts)  # fallback to gpt-4 cl100k-base

            if self.tools:
                # Convert tools to dict format for token counting
                tool_dicts = [tool["function"] if isinstance(tool, dict) and "function" in tool else tool for tool in self.tools]
                self.fallback_input_tokens += num_tokens_from_functions(tool_dicts)

        prev_message_type = None
        message_index = 0
        try:
            async with stream:
                async for chunk in stream:
                    try:
                        async for message in self._process_chunk(chunk, ttft_span, prev_message_type, message_index):
                            new_message_type = message.message_type
                            if new_message_type != prev_message_type:
                                if prev_message_type != None:
                                    message_index += 1
                                prev_message_type = new_message_type
                            yield message
                    except (asyncio.CancelledError, RunCancelledException) as e:
                        import traceback

                        self.stream_was_cancelled = True
                        logger.warning(
                            "Stream was cancelled (%s). Attempting to process current event. "
                            f"Events received so far: {self.total_events_received}, last event: {self.last_event_type}. "
                            f"Error: %s, trace: %s",
                            type(e).__name__,
                            e,
                            traceback.format_exc(),
                        )
                        async for message in self._process_chunk(chunk, ttft_span, prev_message_type, message_index):
                            new_message_type = message.message_type
                            if new_message_type != prev_message_type:
                                if prev_message_type != None:
                                    message_index += 1
                                prev_message_type = new_message_type
                            yield message

                        # Don't raise the exception here
                        continue

                # Stream iterator exited normally
                logger.info(
                    f"Chat Completions stream iterator exited. "
                    f"Received {self.total_events_received} events, "
                    f"last event: {self.last_event_type}"
                )

        except Exception as e:
            import traceback

            logger.exception("Error processing stream: %s", e)
            if ttft_span:
                ttft_span.add_event(
                    name="stop_reason",
                    attributes={"stop_reason": StopReasonType.error.value, "error": str(e), "stacktrace": traceback.format_exc()},
                )
            yield LettaStopReason(stop_reason=StopReasonType.error)
            raise e
        finally:
            # Check if cancellation was signaled via shared event
            if self.cancellation_event and self.cancellation_event.is_set():
                self.stream_was_cancelled = True

            logger.info(
                f"OpenAIStreamingInterface: Stream processing complete. "
                f"Received {self.total_events_received} events, "
                f"last event: {self.last_event_type}, "
                f"stream was cancelled: {self.stream_was_cancelled}"
            )

    async def _process_chunk(
        self,
        chunk: ChatCompletionChunk,
        ttft_span: Optional["Span"] = None,
        prev_message_type: Optional[str] = None,
        message_index: int = 0,
    ) -> AsyncGenerator[LettaMessage | LettaStopReason, None]:
        # Track events for diagnostics
        self.total_events_received += 1
        self.last_event_type = "ChatCompletionChunk"
        # Track events for diagnostics
        self.total_events_received += 1
        self.last_event_type = "ChatCompletionChunk"

        if not self.model or not self.message_id:
            self.model = chunk.model
            self.message_id = chunk.id

        # track usage
        if chunk.usage:
            self.input_tokens += chunk.usage.prompt_tokens
            self.output_tokens += chunk.usage.completion_tokens

        if chunk.choices:
            choice = chunk.choices[0]
            message_delta = choice.delta

            if message_delta.tool_calls is not None and len(message_delta.tool_calls) > 0:
                tool_call = message_delta.tool_calls[0]

                # For OpenAI reasoning models, emit a hidden reasoning message before the first tool call
                if not self.emitted_hidden_reasoning and is_openai_reasoning_model(self.model) and not self.put_inner_thoughts_in_kwarg:
                    self.emitted_hidden_reasoning = True
                    if prev_message_type and prev_message_type != "hidden_reasoning_message":
                        message_index += 1
                    hidden_message = HiddenReasoningMessage(
                        id=self.letta_message_id,
                        date=datetime.now(timezone.utc),
                        state="omitted",
                        hidden_reasoning=None,
                        otid=Message.generate_otid_from_id(self.letta_message_id, message_index),
                        run_id=self.run_id,
                        step_id=self.step_id,
                    )
                    yield hidden_message
                    prev_message_type = hidden_message.message_type
                    message_index += 1  # Increment for the next message

                if tool_call.function.name:
                    # If we're waiting for the first key, then we should hold back the name
                    # ie add it to a buffer instead of returning it as a chunk
                    self._append_function_name(tool_call.function.name)

                if tool_call.id:
                    # Buffer until next time
                    self._append_function_id(tool_call.id)

                if tool_call.function.arguments:
                    # updates_main_json, updates_inner_thoughts = self.function_args_reader.process_fragment(tool_call.function.arguments)
                    self._append_current_function_arguments(tool_call.function.arguments)
                    updates_main_json, updates_inner_thoughts = self.function_args_reader.process_fragment(tool_call.function.arguments)

                    if self.is_openai_proxy:
                        # Use approximate counting for fallback (sync method)
                        self.fallback_output_tokens += self._fallback_token_counter._approx_token_count(tool_call.function.arguments)

                    # If we have inner thoughts, we should output them as a chunk
                    if updates_inner_thoughts:
                        if prev_message_type and prev_message_type != "reasoning_message":
                            message_index += 1
                        self.reasoning_messages.append(updates_inner_thoughts)
                        reasoning_message = ReasoningMessage(
                            id=self.letta_message_id,
                            date=datetime.now(timezone.utc),
                            reasoning=updates_inner_thoughts,
                            # name=name,
                            otid=Message.generate_otid_from_id(self.letta_message_id, message_index),
                            run_id=self.run_id,
                            step_id=self.step_id,
                        )
                        prev_message_type = reasoning_message.message_type
                        yield reasoning_message

                        # Additionally inner thoughts may stream back with a chunk of main JSON
                        # In that case, since we can only return a chunk at a time, we should buffer it
                        if updates_main_json:
                            if self._function_args_buffer_parts is None:
                                self._function_args_buffer_parts = [updates_main_json]
                            else:
                                self._function_args_buffer_parts.append(updates_main_json)

                    # If we have main_json, we should output a ToolCallMessage
                    elif updates_main_json:
                        # If there's something in the function_name buffer, we should release it first
                        # NOTE: we could output it as part of a chunk that has both name and args,
                        #       however the frontend may expect name first, then args, so to be
                        #       safe we'll output name first in a separate chunk
                        if self._get_function_name_buffer():
                            # use_assisitant_message means that we should also not release main_json raw, and instead should only release the contents of "message": "..."
                            if self.use_assistant_message and self._get_function_name_buffer() == self.assistant_message_tool_name:
                                # Store the ID of the tool call so allow skipping the corresponding response
                                if self._get_function_id_buffer():
                                    self.prev_assistant_message_id = self._get_function_id_buffer()
                                # Reset message reader at the start of a new send_message stream
                                self.assistant_message_json_reader.reset()

                            else:
                                if prev_message_type and prev_message_type != "tool_call_message":
                                    message_index += 1
                                self.tool_call_name = str(self._get_function_name_buffer())
                                if self.tool_call_name in self.requires_approval_tools:
                                    tool_call_msg = ApprovalRequestMessage(
                                        id=decrement_message_uuid(self.letta_message_id),
                                        date=datetime.now(timezone.utc),
                                        tool_call=ToolCallDelta(
                                            name=self._get_function_name_buffer(),
                                            arguments=None,
                                            tool_call_id=self._get_current_function_id(),
                                        ),
                                        otid=Message.generate_otid_from_id(decrement_message_uuid(self.letta_message_id), -1),
                                        run_id=self.run_id,
                                        step_id=self.step_id,
                                    )
                                else:
                                    tool_call_delta = ToolCallDelta(
                                        name=self._get_function_name_buffer(),
                                        arguments=None,
                                        tool_call_id=self._get_current_function_id(),
                                    )
                                    tool_call_msg = ToolCallMessage(
                                        id=self.letta_message_id,
                                        date=datetime.now(timezone.utc),
                                        tool_call=tool_call_delta,
                                        tool_calls=tool_call_delta,
                                        otid=Message.generate_otid_from_id(self.letta_message_id, message_index),
                                        run_id=self.run_id,
                                        step_id=self.step_id,
                                    )
                                prev_message_type = tool_call_msg.message_type
                                yield tool_call_msg

                            # Record what the last function name we flushed was
                            self.last_flushed_function_name = self._get_function_name_buffer()
                            # Always refresh flushed id to current buffer for this tool call
                            self.last_flushed_function_id = self._get_function_id_buffer()
                            # Clear the buffer
                            self._clear_function_buffers()
                            # Since we're clearing the name buffer, we should store
                            # any updates to the arguments inside a separate buffer

                            # Add any main_json updates to the arguments buffer
                            if self._function_args_buffer_parts is None:
                                self._function_args_buffer_parts = [updates_main_json]
                            else:
                                self._function_args_buffer_parts.append(updates_main_json)

                        # If there was nothing in the name buffer, we can proceed to
                        # output the arguments chunk as a ToolCallMessage
                        else:
                            # use_assistant_message means that we should also not release main_json raw, and instead should only release the contents of "message": "..."
                            if self.use_assistant_message and (
                                self.last_flushed_function_name is not None
                                and self.last_flushed_function_name == self.assistant_message_tool_name
                            ):
                                # Minimal, robust extraction: only emit the value of "message".
                                # If we buffered a prefix while name was streaming, feed it first.
                                if self._function_args_buffer_parts:
                                    payload = "".join(self._function_args_buffer_parts + [tool_call.function.arguments])
                                    self._function_args_buffer_parts = None
                                else:
                                    payload = tool_call.function.arguments
                                extracted = self.assistant_message_json_reader.process_json_chunk(payload)
                                extracted = sanitize_streamed_message_content(extracted or "")
                                if extracted:
                                    if prev_message_type and prev_message_type != "assistant_message":
                                        message_index += 1
                                    assistant_message = AssistantMessage(
                                        id=self.letta_message_id,
                                        date=datetime.now(timezone.utc),
                                        content=extracted,
                                        otid=Message.generate_otid_from_id(self.letta_message_id, message_index),
                                        run_id=self.run_id,
                                        step_id=self.step_id,
                                    )
                                    prev_message_type = assistant_message.message_type
                                    yield assistant_message
                                    # Store the ID of the tool call so allow skipping the corresponding response
                                    if self._get_function_id_buffer():
                                        self.prev_assistant_message_id = self._get_function_id_buffer()
                            else:
                                # There may be a buffer from a previous chunk, for example
                                # if the previous chunk had arguments but we needed to flush name
                                if self._function_args_buffer_parts:
                                    # In this case, we should release the buffer + new data at once
                                    combined_chunk = "".join(self._function_args_buffer_parts + [updates_main_json])
                                    if prev_message_type and prev_message_type != "tool_call_message":
                                        message_index += 1
                                    if self._get_function_name_buffer() in self.requires_approval_tools:
                                        tool_call_msg = ApprovalRequestMessage(
                                            id=decrement_message_uuid(self.letta_message_id),
                                            date=datetime.now(timezone.utc),
                                            tool_call=ToolCallDelta(
                                                name=self._get_function_name_buffer(),
                                                arguments=combined_chunk,
                                                tool_call_id=self._get_current_function_id(),
                                            ),
                                            # name=name,
                                            otid=Message.generate_otid_from_id(decrement_message_uuid(self.letta_message_id), -1),
                                            run_id=self.run_id,
                                            step_id=self.step_id,
                                        )
                                    else:
                                        tool_call_delta = ToolCallDelta(
                                            name=self._get_function_name_buffer(),
                                            arguments=combined_chunk,
                                            tool_call_id=self._get_current_function_id(),
                                        )
                                        tool_call_msg = ToolCallMessage(
                                            id=self.letta_message_id,
                                            date=datetime.now(timezone.utc),
                                            tool_call=tool_call_delta,
                                            tool_calls=tool_call_delta,
                                            # name=name,
                                            otid=Message.generate_otid_from_id(self.letta_message_id, message_index),
                                            run_id=self.run_id,
                                            step_id=self.step_id,
                                        )
                                    prev_message_type = tool_call_msg.message_type
                                    yield tool_call_msg
                                    # clear buffer
                                    self._function_args_buffer_parts = None
                                    self._function_id_parts = []
                                else:
                                    # If there's no buffer to clear, just output a new chunk with new data
                                    if prev_message_type and prev_message_type != "tool_call_message":
                                        message_index += 1
                                    if self._get_function_name_buffer() in self.requires_approval_tools:
                                        tool_call_msg = ApprovalRequestMessage(
                                            id=decrement_message_uuid(self.letta_message_id),
                                            date=datetime.now(timezone.utc),
                                            tool_call=ToolCallDelta(
                                                name=None,
                                                arguments=updates_main_json,
                                                tool_call_id=self._get_current_function_id(),
                                            ),
                                            # name=name,
                                            otid=Message.generate_otid_from_id(decrement_message_uuid(self.letta_message_id), -1),
                                            run_id=self.run_id,
                                            step_id=self.step_id,
                                        )
                                    else:
                                        tool_call_delta = ToolCallDelta(
                                            name=None,
                                            arguments=updates_main_json,
                                            tool_call_id=self._get_current_function_id(),
                                        )
                                        tool_call_msg = ToolCallMessage(
                                            id=self.letta_message_id,
                                            date=datetime.now(timezone.utc),
                                            tool_call=tool_call_delta,
                                            tool_calls=tool_call_delta,
                                            # name=name,
                                            otid=Message.generate_otid_from_id(self.letta_message_id, message_index),
                                            run_id=self.run_id,
                                            step_id=self.step_id,
                                        )
                                    prev_message_type = tool_call_msg.message_type
                                    yield tool_call_msg
                                    self._function_id_parts = []


class SimpleOpenAIStreamingInterface:
    """
    Encapsulates the logic for streaming responses from OpenAI.
    This class handles parsing of partial tokens, pre-execution messages,
    and detection of tool call events.
    """

    def __init__(
        self,
        is_openai_proxy: bool = False,
        messages: Optional[list] = None,
        tools: Optional[list] = None,
        requires_approval_tools: list = [],
        model: str = None,
        run_id: str | None = None,
        step_id: str | None = None,
        cancellation_event: Optional["asyncio.Event"] = None,
    ):
        self.run_id = run_id
        self.step_id = step_id
        self.cancellation_event = cancellation_event
        # Premake IDs for database writes
        self.letta_message_id = Message.generate_id()

        self.message_id = None
        self.model = model

        # Token counters (from OpenAI usage)
        self.input_tokens = 0
        self.output_tokens = 0

        # Cache and reasoning token tracking
        # None means "not reported by provider", 0 means "provider reported 0"
        self.cached_tokens: int | None = None
        self.reasoning_tokens: int | None = None

        # Raw usage from provider (for transparent logging in provider trace)
        self.raw_usage: dict | None = None

        # Diagnostic: track last event for debugging
        self.last_event_type: str | None = None
        self.total_events_received: int = 0
        self.stream_was_cancelled: bool = False

        # Fallback token counters (using tiktoken cl200k-base)
        self.fallback_input_tokens = 0
        self.fallback_output_tokens = 0

        # Store messages and tools for fallback counting
        self.is_openai_proxy = is_openai_proxy
        self.messages = messages or []
        self.tools = tools or []

        # Accumulate per-index tool call fragments and preserve order
        self._tool_calls_acc: dict[int, dict[str, str]] = {}
        self._tool_call_start_order: list[int] = []

        self.content_messages = []
        self.emitted_hidden_reasoning = False  # Track if we've emitted hidden reasoning message

        self.requires_approval_tools = requires_approval_tools

    def get_content(self) -> list[TextContent | OmittedReasoningContent | ReasoningContent]:
        shown_omitted = False
        concat_content = ""
        merged_messages = []
        reasoning_content = []
        concat_content_parts: list[str] = []

        for msg in self.content_messages:
            if isinstance(msg, HiddenReasoningMessage) and not shown_omitted:
                merged_messages.append(OmittedReasoningContent())
                shown_omitted = True
            elif isinstance(msg, ReasoningMessage):
                reasoning_content.append(msg.reasoning)
            elif isinstance(msg, AssistantMessage):
                if isinstance(msg.content, list):
                    concat_content_parts.append("".join([c.text for c in msg.content]))
                else:
                    concat_content_parts.append(msg.content)

        if reasoning_content:
            combined_reasoning = "".join(reasoning_content)
            # Only reroute reasoning into content for DeepSeek streams when no assistant text was emitted
            # and no tool calls were produced (i.e., a reasoning-only final answer).
            is_deepseek = bool(self.model and self.model.startswith("deepseek"))
            produced_tool_calls = bool(self._tool_calls_acc)
            if is_deepseek and not concat_content_parts and not produced_tool_calls:
                concat_content_parts.append(combined_reasoning)
            else:
                merged_messages.append(ReasoningContent(is_native=True, reasoning=combined_reasoning, signature=None))

        if concat_content_parts:
            merged_messages.append(TextContent(text="".join(concat_content_parts)))

        return merged_messages

    def get_tool_call_objects(self) -> list[ToolCall]:
        """Return finalized tool calls (parallel supported)."""
        if not self._tool_calls_acc:
            return []
        ordered_indices = [i for i in self._tool_call_start_order if i in self._tool_calls_acc]
        result: list[ToolCall] = []
        for idx in ordered_indices:
            ctx = self._tool_calls_acc[idx]
            name = "".join(ctx.get("name_parts", [])) if "name_parts" in ctx else ctx.get("name", "")
            args = "".join(ctx.get("arguments_parts", [])) if "arguments_parts" in ctx else ctx.get("arguments", "")
            call_id = "".join(ctx.get("id_parts", [])) if "id_parts" in ctx else ctx.get("id", "")
            if call_id and name:
                result.append(ToolCall(id=call_id, function=FunctionCall(arguments=args or "", name=name)))
        return result

    def get_tool_call_object(self) -> ToolCall:
        """Backwards-compatible single tool call accessor (first tool if multiple)."""
        calls = self.get_tool_call_objects()
        if not calls:
            raise ValueError("No tool calls available")
        return calls[0]

    async def process(
        self,
        stream: AsyncStream[ChatCompletionChunk],
        ttft_span: Optional["Span"] = None,
    ) -> AsyncGenerator[LettaMessage | LettaStopReason, None]:
        """
        Iterates over the OpenAI stream, yielding SSE events.
        It also collects tokens and detects if a tool call is triggered.
        """
        # Fallback input token counting - this should only be required for non-OpenAI providers using the OpenAI client (e.g. LMStudio)
        if self.is_openai_proxy:
            if self.messages:
                # Convert messages to dict format for token counting
                message_dicts = [msg.to_openai_dict() if hasattr(msg, "to_openai_dict") else msg for msg in self.messages]
                message_dicts = [m for m in message_dicts if m is not None]
                self.fallback_input_tokens = num_tokens_from_messages(message_dicts)  # fallback to gpt-4 cl100k-base

            if self.tools:
                # Convert tools to dict format for token counting
                tool_dicts = [tool["function"] if isinstance(tool, dict) and "function" in tool else tool for tool in self.tools]
                self.fallback_input_tokens += num_tokens_from_functions(tool_dicts)

        prev_message_type = None
        message_index = 0
        try:
            async with stream:
                # For reasoning models, emit a hidden reasoning message before the first chunk
                if not self.emitted_hidden_reasoning and is_openai_reasoning_model(self.model):
                    self.emitted_hidden_reasoning = True
                    if prev_message_type and prev_message_type != "hidden_reasoning_message":
                        message_index += 1
                    hidden_message = HiddenReasoningMessage(
                        id=self.letta_message_id,
                        date=datetime.now(timezone.utc),
                        state="omitted",
                        hidden_reasoning=None,
                        otid=Message.generate_otid_from_id(self.letta_message_id, message_index),
                        run_id=self.run_id,
                        step_id=self.step_id,
                    )
                    self.content_messages.append(hidden_message)
                    prev_message_type = hidden_message.message_type
                    yield hidden_message

                async for chunk in stream:
                    try:
                        async for message in self._process_chunk(chunk, ttft_span, prev_message_type, message_index):
                            new_message_type = message.message_type
                            if new_message_type != prev_message_type:
                                if prev_message_type != None:
                                    message_index += 1
                                prev_message_type = new_message_type
                            yield message
                    except (asyncio.CancelledError, RunCancelledException) as e:
                        import traceback

                        self.stream_was_cancelled = True
                        logger.warning(
                            "Stream was cancelled (%s). Attempting to process current event. "
                            f"Events received so far: {self.total_events_received}, last event: {self.last_event_type}. "
                            f"Error: %s, trace: %s",
                            type(e).__name__,
                            e,
                            traceback.format_exc(),
                        )
                        async for message in self._process_chunk(chunk, ttft_span, prev_message_type, message_index):
                            new_message_type = message.message_type
                            if new_message_type != prev_message_type:
                                if prev_message_type != None:
                                    message_index += 1
                                prev_message_type = new_message_type
                            yield message

                        # Don't raise the exception here
                        continue

                # Stream iterator exited normally
                logger.info(
                    f"Chat Completions stream iterator exited (SimpleOpenAIStreamingInterface). "
                    f"Received {self.total_events_received} events, "
                    f"last event: {self.last_event_type}"
                )

        except Exception as e:
            import traceback

            # IMPORTANT: If this is a context window overflow, we should propagate the
            # exception upward so the agent loop can compact/summarize + retry.
            # Yielding an error stop reason here would prematurely terminate the user's
            # stream even though a retry path exists.
            msg = str(e)
            if is_context_window_overflow_message(msg):
                raise

            logger.exception("Error processing stream: %s", e)
            if ttft_span:
                ttft_span.add_event(
                    name="stop_reason",
                    attributes={"stop_reason": StopReasonType.error.value, "error": str(e), "stacktrace": traceback.format_exc()},
                )
            yield LettaStopReason(stop_reason=StopReasonType.error)
            raise e
        finally:
            # Check if cancellation was signaled via shared event
            if self.cancellation_event and self.cancellation_event.is_set():
                self.stream_was_cancelled = True

            logger.info(
                f"SimpleOpenAIStreamingInterface: Stream processing complete. "
                f"Received {self.total_events_received} events, "
                f"last event: {self.last_event_type}, "
                f"stream was cancelled: {self.stream_was_cancelled}"
            )

    async def _process_chunk(
        self,
        chunk: ChatCompletionChunk,
        ttft_span: Optional["Span"] = None,
        prev_message_type: Optional[str] = None,
        message_index: int = 0,
    ) -> AsyncGenerator[LettaMessage | LettaStopReason, None]:
        if not self.model or not self.message_id:
            self.model = chunk.model
            self.message_id = chunk.id

        # track usage
        if chunk.usage:
            self.input_tokens += chunk.usage.prompt_tokens
            self.output_tokens += chunk.usage.completion_tokens
            # Store raw usage for transparent provider trace logging
            try:
                self.raw_usage = chunk.usage.model_dump(exclude_none=True)
            except Exception as e:
                logger.error(f"Failed to capture raw_usage from OpenAI chat completion chunk: {e}")
                self.raw_usage = None
            # Capture cache token details (OpenAI)
            # Use `is not None` to capture 0 values (meaning "provider reported 0 cached tokens")
            if hasattr(chunk.usage, "prompt_tokens_details") and chunk.usage.prompt_tokens_details:
                details = chunk.usage.prompt_tokens_details
                if hasattr(details, "cached_tokens") and details.cached_tokens is not None:
                    if self.cached_tokens is None:
                        self.cached_tokens = 0
                    self.cached_tokens += details.cached_tokens
            # Capture reasoning token details (OpenAI o1/o3)
            # Use `is not None` to capture 0 values (meaning "provider reported 0 reasoning tokens")
            if hasattr(chunk.usage, "completion_tokens_details") and chunk.usage.completion_tokens_details:
                details = chunk.usage.completion_tokens_details
                if hasattr(details, "reasoning_tokens") and details.reasoning_tokens is not None:
                    if self.reasoning_tokens is None:
                        self.reasoning_tokens = 0
                    self.reasoning_tokens += details.reasoning_tokens

        if chunk.choices:
            choice = chunk.choices[0]
            message_delta = choice.delta

            if message_delta.content is not None and message_delta.content != "":
                if prev_message_type and prev_message_type != "assistant_message":
                    message_index += 1
                assistant_msg = AssistantMessage(
                    id=self.letta_message_id,
                    content=message_delta.content,
                    date=datetime.now(timezone.utc).isoformat(),
                    otid=Message.generate_otid_from_id(self.letta_message_id, message_index),
                    run_id=self.run_id,
                    step_id=self.step_id,
                )
                self.content_messages.append(assistant_msg)
                prev_message_type = assistant_msg.message_type
                yield assistant_msg

            if (
                hasattr(chunk, "choices")
                and len(chunk.choices) > 0
                and hasattr(chunk.choices[0], "delta")
                and hasattr(chunk.choices[0].delta, "reasoning_content")
            ):
                delta = chunk.choices[0].delta
                reasoning_content = getattr(delta, "reasoning_content", None)
                if reasoning_content is not None and reasoning_content != "":
                    if prev_message_type and prev_message_type != "reasoning_message":
                        message_index += 1
                    reasoning_msg = ReasoningMessage(
                        id=self.letta_message_id,
                        date=datetime.now(timezone.utc).isoformat(),
                        otid=Message.generate_otid_from_id(self.letta_message_id, message_index),
                        source="reasoner_model",
                        reasoning=reasoning_content,
                        signature=None,
                        run_id=self.run_id,
                        step_id=self.step_id,
                    )
                    self.content_messages.append(reasoning_msg)
                    prev_message_type = reasoning_msg.message_type
                    yield reasoning_msg

            if message_delta.tool_calls is not None and len(message_delta.tool_calls) > 0:
                # Accumulate per-index tool call fragments and emit deltas
                for tool_call in message_delta.tool_calls:
                    if (
                        not (tool_call.function and (tool_call.function.name or tool_call.function.arguments))
                        and not tool_call.id
                        and getattr(tool_call, "index", None) is None
                    ):
                        continue

                    idx = getattr(tool_call, "index", None)
                    if idx is None:
                        idx = 0

                    if idx not in self._tool_call_start_order:
                        self._tool_call_start_order.append(idx)
                    if idx not in self._tool_calls_acc:
                        self._tool_calls_acc[idx] = {"name_parts": [], "arguments_parts": [], "id_parts": []}
                    acc = self._tool_calls_acc[idx]

                    if tool_call.function and tool_call.function.name:
                        acc["name_parts"].append(tool_call.function.name)
                    if tool_call.function and tool_call.function.arguments:
                        acc["arguments_parts"].append(tool_call.function.arguments)
                    if tool_call.id:
                        acc["id_parts"].append(tool_call.id)

                    # Resolve stable id from accumulator; OpenAI may omit id on argument-only deltas
                    resolved_id = "".join(acc.get("id_parts", [])) if acc.get("id_parts") else None
                    # If we don't yet have an id for this tool_call index, skip emitting unusable delta
                    if resolved_id is None:
                        continue

                    delta = ToolCallDelta(
                        name=tool_call.function.name if (tool_call.function and tool_call.function.name) else None,
                        arguments=tool_call.function.arguments if (tool_call.function and tool_call.function.arguments) else None,
                        tool_call_id=resolved_id,
                    )

                    _curr_name = "".join(acc.get("name_parts", [])) if "name_parts" in acc else acc.get("name", "")
                    if _curr_name and _curr_name in self.requires_approval_tools:
                        tool_call_msg = ApprovalRequestMessage(
                            id=decrement_message_uuid(self.letta_message_id),
                            date=datetime.now(timezone.utc),
                            tool_call=delta,
                            otid=Message.generate_otid_from_id(decrement_message_uuid(self.letta_message_id), -1),
                            run_id=self.run_id,
                            step_id=self.step_id,
                        )
                    else:
                        if prev_message_type and prev_message_type != "tool_call_message":
                            message_index += 1
                        tool_call_msg = ToolCallMessage(
                            id=self.letta_message_id,
                            date=datetime.now(timezone.utc),
                            tool_call=delta,
                            tool_calls=delta,
                            otid=Message.generate_otid_from_id(self.letta_message_id, message_index),
                            run_id=self.run_id,
                            step_id=self.step_id,
                        )
                        prev_message_type = tool_call_msg.message_type
                    yield tool_call_msg


class SimpleOpenAIResponsesStreamingInterface:
    """
    Encapsulates the logic for streaming responses from OpenAI Responses API.
    """

    def __init__(
        self,
        is_openai_proxy: bool = False,
        messages: Optional[list] = None,
        tools: Optional[list] = None,
        requires_approval_tools: list = [],
        model: str = None,
        run_id: str | None = None,
        step_id: str | None = None,
        cancellation_event: Optional["asyncio.Event"] = None,
    ):
        self.is_openai_proxy = is_openai_proxy
        self.messages = messages
        self.tools = tools
        self.requires_approval_tools = requires_approval_tools
        # We need to store the name for approvals
        self.tool_call_name = None
        # Responses API parallel tool call tracking: map output_index/item_id -> (call_id, name)
        self._tool_map_by_output_index: dict[int, tuple[str | None, str | None]] = {}
        self._tool_map_by_item_id: dict[str, tuple[str | None, str | None]] = {}
        # ID responses used
        self.message_id = None
        self.run_id = run_id
        self.step_id = step_id
        self.cancellation_event = cancellation_event

        # Premake IDs for database writes
        self.letta_message_id = Message.generate_id()
        self.model = model
        self.final_response: Optional[ParsedResponse] = None

        # Token counters
        self.input_tokens = 0
        self.output_tokens = 0

        # Cache and reasoning token tracking
        # None means "not reported by provider", 0 means "provider reported 0"
        self.cached_tokens: int | None = None
        self.reasoning_tokens: int | None = None

        # Raw usage from provider (for transparent logging in provider trace)
        self.raw_usage: dict | None = None

        # Diagnostic: track last event for debugging
        self.last_event_type: str | None = None
        self.total_events_received: int = 0
        self.stream_was_cancelled: bool = False

    # -------- Mapping helpers (no broad try/except) --------
    def _record_tool_mapping(self, event: object, item: object) -> tuple[str | None, str | None, int | None, str | None]:
        """Record call_id/name mapping for this tool-call using output_index and item.id if present.
        Returns (call_id, name, output_index, item_id)."""
        call_id = getattr(item, "call_id", None)
        name = getattr(item, "name", None)
        output_index = getattr(event, "output_index", None)
        item_id = getattr(item, "id", None)
        if isinstance(output_index, int):
            self._tool_map_by_output_index[output_index] = (call_id, name)
        if isinstance(item_id, str) and item_id:
            self._tool_map_by_item_id[item_id] = (call_id, name)
        return call_id, name, output_index if isinstance(output_index, int) else None, item_id if isinstance(item_id, str) else None

    def _resolve_mapping_for_delta(self, event: object) -> tuple[str | None, str | None, int | None, str | None]:
        """Resolve (call_id, name) for an arguments-delta event. Returns mapping plus keys used."""
        output_index = getattr(event, "output_index", None)
        if isinstance(output_index, int) and output_index in self._tool_map_by_output_index:
            call_id, name = self._tool_map_by_output_index[output_index]
            return call_id, name, output_index, None
        item_id = getattr(event, "item_id", None)
        if isinstance(item_id, str) and item_id in self._tool_map_by_item_id:
            call_id, name = self._tool_map_by_item_id[item_id]
            return call_id, name, None, item_id
        return None, None, output_index if isinstance(output_index, int) else None, item_id if isinstance(item_id, str) else None

    # (No buffering: we rely on Responses event order — tool_call added before arg deltas.)

    def get_content(self) -> list[TextContent | SummarizedReasoningContent]:
        """This includes both SummarizedReasoningContent and TextContent"""
        if self.final_response is None:
            logger.warning(
                "No final response available - stream may have been interrupted or ResponseCompletedEvent was not received. "
                f"Diagnostic info: received {self.total_events_received} events total, "
                f"last event type: {self.last_event_type}, "
                f"stream was cancelled: {self.stream_was_cancelled}. "
                "Returning empty content list."
            )
            return []

        content = []
        for response in self.final_response.output:
            if isinstance(response, ResponseReasoningItem):
                # TODO consider cleaning up our representation to not require indexing
                letta_summary = [SummarizedReasoningContentPart(index=i, text=part.text) for i, part in enumerate(response.summary)]
                content.append(
                    SummarizedReasoningContent(
                        id=response.id,
                        summary=letta_summary,
                        encrypted_content=response.encrypted_content,
                    )
                )
            elif isinstance(response, ResponseOutputMessage):
                if len(response.content) == 1:
                    content.append(
                        TextContent(
                            text=response.content[0].text,
                        )
                    )
                else:
                    raise ValueError(f"Got {len(response.content)} content parts, expected 1")

        return content

    def get_tool_call_objects(self) -> list[ToolCall]:
        """Return finalized tool calls (parallel supported) from final response."""
        if self.final_response is None:
            return []

        tool_calls: list[ToolCall] = []
        for item in self.final_response.output:
            if isinstance(item, ResponseFunctionToolCall):
                call_id = item.call_id
                name = item.name
                arguments = item.arguments
                if call_id and name is not None:
                    tool_calls.append(
                        ToolCall(
                            id=call_id,
                            function=FunctionCall(
                                name=name,
                                arguments=arguments,
                            ),
                        )
                    )

        return tool_calls

    def get_tool_call_object(self) -> ToolCall:
        calls = self.get_tool_call_objects()
        if not calls:
            raise ValueError("No tool calls available")
        return calls[0]

    async def process(
        self,
        stream: AsyncStream[ResponseStreamEvent],
        ttft_span: Optional["Span"] = None,
    ) -> AsyncGenerator[LettaMessage | LettaStopReason, None]:
        """
        Iterates over the OpenAI stream, yielding SSE events.
        It also collects tokens and detects if a tool call is triggered.
        """
        # Fallback input token counting - this should only be required for non-OpenAI providers using the OpenAI client (e.g. LMStudio)
        if self.is_openai_proxy:
            raise NotImplementedError("OpenAI proxy is not supported for OpenAI Responses API")

        prev_message_type = None
        message_index = 0
        try:
            logger.info("Starting ResponsesAPI stream processing")
            async with stream:
                async for event in stream:
                    try:
                        async for message in self._process_event(event, ttft_span, prev_message_type, message_index):
                            new_message_type = message.message_type
                            if new_message_type != prev_message_type:
                                if prev_message_type != None:
                                    message_index += 1
                                prev_message_type = new_message_type
                            yield message
                    except (TypeError, AttributeError, KeyError, ValueError) as e:
                        # Event parsing/processing error - log and skip this event
                        import traceback

                        logger.error(
                            f"Error processing event {type(event).__name__} at position {self.total_events_received}: {e}. "
                            f"Event data: {event if hasattr(event, '__dict__') else str(event)[:500]}. "
                            f"Skipping this event and continuing stream.",
                            exc_info=True,
                        )
                        # Continue to next event rather than killing the stream
                        continue
                    except (asyncio.CancelledError, RunCancelledException) as e:
                        import traceback

                        self.stream_was_cancelled = True
                        logger.warning(
                            "Stream was cancelled (%s). Attempting to process current event. "
                            f"Events received so far: {self.total_events_received}, last event: {self.last_event_type}. "
                            f"Error: %s, trace: %s",
                            type(e).__name__,
                            e,
                            traceback.format_exc(),
                        )
                        async for message in self._process_event(event, ttft_span, prev_message_type, message_index):
                            new_message_type = message.message_type
                            if new_message_type != prev_message_type:
                                if prev_message_type != None:
                                    message_index += 1
                                prev_message_type = new_message_type
                            yield message

                        # Don't raise the exception here
                        continue

        except Exception as e:
            import traceback

            logger.exception("Error processing stream: %s", e)
            if ttft_span:
                ttft_span.add_event(
                    name="stop_reason",
                    attributes={"stop_reason": StopReasonType.error.value, "error": str(e), "stacktrace": traceback.format_exc()},
                )
            yield LettaStopReason(stop_reason=StopReasonType.error)
            raise e
        finally:
            # Check if cancellation was signaled via shared event
            if self.cancellation_event and self.cancellation_event.is_set():
                self.stream_was_cancelled = True

            logger.info(
                f"ResponsesAPI Stream processing complete. "
                f"Received {self.total_events_received} events, "
                f"last event: {self.last_event_type}, "
                f"has final_response: {self.final_response is not None}, "
                f"stream was cancelled: {self.stream_was_cancelled}"
            )

    async def _process_event(
        self,
        event: ResponseStreamEvent,
        ttft_span: Optional["Span"] = None,
        prev_message_type: Optional[str] = None,
        message_index: int = 0,
    ) -> AsyncGenerator[LettaMessage | LettaStopReason, None]:
        # Track events for diagnostics
        self.total_events_received += 1
        self.last_event_type = type(event).__name__
        if isinstance(event, ResponseCreatedEvent):
            # No-op, just had the input events
            return
            # or yield None?

        elif isinstance(event, ResponseInProgressEvent):
            # No-op, just an indicator that we've started
            return

        elif isinstance(event, ResponseOutputItemAddedEvent):
            new_event_item = event.item

            # New "item" was added, can be reasoning, tool call, or content
            if isinstance(new_event_item, ResponseReasoningItem):
                # Look for summary delta, or encrypted_content
                summary = new_event_item.summary
                content = new_event_item.content  # NOTE: always none
                encrypted_content = new_event_item.encrypted_content
                # TODO change to summarize reasoning message, but we need to figure out the streaming indices of summary problem
                concat_summary = "".join([s.text for s in summary])
                if concat_summary != "":
                    if prev_message_type and prev_message_type != "reasoning_message":
                        message_index += 1
                    yield ReasoningMessage(
                        id=self.letta_message_id,
                        date=datetime.now(timezone.utc).isoformat(),
                        otid=Message.generate_otid_from_id(self.letta_message_id, message_index),
                        source="reasoner_model",
                        reasoning=concat_summary,
                        run_id=self.run_id,
                        step_id=self.step_id,
                    )
                    prev_message_type = "reasoning_message"
                else:
                    return

            elif isinstance(new_event_item, ResponseFunctionToolCall):
                # Look for call_id, name, and possibly arguments (though likely always empty string)
                call_id = new_event_item.call_id
                name = new_event_item.name
                arguments = new_event_item.arguments
                # cache for approval if/elses
                self.tool_call_name = name
                # Record mapping so subsequent argument deltas can be associated
                self._record_tool_mapping(event, new_event_item)
                if self.tool_call_name and self.tool_call_name in self.requires_approval_tools:
                    yield ApprovalRequestMessage(
                        id=decrement_message_uuid(self.letta_message_id),
                        otid=Message.generate_otid_from_id(decrement_message_uuid(self.letta_message_id), -1),
                        date=datetime.now(timezone.utc),
                        tool_call=ToolCallDelta(
                            name=name,
                            arguments=arguments if arguments != "" else None,
                            tool_call_id=call_id,
                        ),
                        run_id=self.run_id,
                        step_id=self.step_id,
                    )
                else:
                    if prev_message_type and prev_message_type != "tool_call_message":
                        message_index += 1
                    tool_call_delta = ToolCallDelta(
                        name=name,
                        arguments=arguments if arguments != "" else None,
                        tool_call_id=call_id,
                    )
                    yield ToolCallMessage(
                        id=self.letta_message_id,
                        otid=Message.generate_otid_from_id(self.letta_message_id, message_index),
                        date=datetime.now(timezone.utc),
                        tool_call=tool_call_delta,
                        tool_calls=tool_call_delta,
                        run_id=self.run_id,
                        step_id=self.step_id,
                    )
                    prev_message_type = "tool_call_message"

            elif isinstance(new_event_item, ResponseOutputMessage):
                # Look for content (may be empty list []), or contain ResponseOutputText
                if len(new_event_item.content) > 0:
                    for content_item in new_event_item.content:
                        if isinstance(content_item, ResponseOutputText):
                            # Add this as a AssistantMessage part
                            if prev_message_type and prev_message_type != "assistant_message":
                                message_index += 1
                            yield AssistantMessage(
                                id=self.letta_message_id,
                                otid=Message.generate_otid_from_id(self.letta_message_id, message_index),
                                date=datetime.now(timezone.utc),
                                content=content_item.text,
                                run_id=self.run_id,
                                step_id=self.step_id,
                            )
                            prev_message_type = "assistant_message"
                else:
                    return

            else:
                # Other types we don't handle, ignore
                return

        # Reasoning summary is streaming in
        # TODO / FIXME return a SummaryReasoning type
        elif isinstance(event, ResponseReasoningSummaryPartAddedEvent):
            # This means the part got added, but likely no content yet (likely empty string)
            summary_index = event.summary_index
            part = event.part

            # If this is a follow-up summary part, we need to add leading newlines
            if summary_index > 1:
                summary_text = "\n\n" + part.text
            else:
                summary_text = part.text

            if prev_message_type and prev_message_type != "reasoning_message":
                message_index += 1
            yield ReasoningMessage(
                id=self.letta_message_id,
                date=datetime.now(timezone.utc).isoformat(),
                otid=Message.generate_otid_from_id(self.letta_message_id, message_index),
                source="reasoner_model",
                reasoning=summary_text,
                run_id=self.run_id,
            )
            prev_message_type = "reasoning_message"

        # Reasoning summary streaming
        elif isinstance(event, ResponseReasoningSummaryTextDeltaEvent):
            # NOTE: the summary is a list with indices
            summary_index = event.summary_index
            delta = event.delta
            if delta != "":
                summary_index = event.summary_index
                # Check if we need to instantiate a fresh new part
                # NOTE: we can probably use the part added and part done events, but this is safer
                # TODO / FIXME return a SummaryReasoning type
                if prev_message_type and prev_message_type != "reasoning_message":
                    message_index += 1
                yield ReasoningMessage(
                    id=self.letta_message_id,
                    date=datetime.now(timezone.utc).isoformat(),
                    otid=Message.generate_otid_from_id(self.letta_message_id, message_index),
                    source="reasoner_model",
                    reasoning=delta,
                    run_id=self.run_id,
                    step_id=self.step_id,
                )
                prev_message_type = "reasoning_message"
            else:
                return

        # Reasoning summary streaming
        elif isinstance(event, ResponseReasoningSummaryTextDoneEvent):
            # NOTE: is this inclusive of the deltas?
            # If not, we should add it to the rolling
            summary_index = event.summary_index
            text = event.text
            return

        # Reasoning summary streaming
        elif isinstance(event, ResponseReasoningSummaryPartDoneEvent):
            # NOTE: this one is definitely inclusive, so can skip
            summary_index = event.summary_index
            # text = event
            return

        # Assistant message streaming
        elif isinstance(event, ResponseContentPartAddedEvent):
            part = event.part
            if isinstance(part, ResponseOutputText):
                # Append to running
                return  # TODO
            else:
                # TODO handle
                return

        # Assistant message streaming
        elif isinstance(event, ResponseTextDeltaEvent):
            delta = event.delta
            if delta != "":
                # Append to running
                if prev_message_type and prev_message_type != "assistant_message":
                    message_index += 1
                yield AssistantMessage(
                    id=self.letta_message_id,
                    otid=Message.generate_otid_from_id(self.letta_message_id, message_index),
                    date=datetime.now(timezone.utc),
                    content=delta,
                    run_id=self.run_id,
                    step_id=self.step_id,
                )
                prev_message_type = "assistant_message"
            else:
                return

        # Assistant message streaming
        elif isinstance(event, ResponseTextDoneEvent):
            # NOTE: inclusive, can skip
            text = event.text
            return

        # Assistant message done
        elif isinstance(event, ResponseContentPartDoneEvent):
            # NOTE: inclusive, can skip
            part = event.part
            return

        # Function calls
        elif isinstance(event, ResponseFunctionCallArgumentsDeltaEvent):
            # only includes delta on args
            delta = event.delta

            # Resolve tool_call_id/name using output_index or item_id
            resolved_call_id, resolved_name, out_idx, item_id = self._resolve_mapping_for_delta(event)

            # Fallback to last seen tool name for approval routing if mapping name missing
            if not resolved_name:
                resolved_name = self.tool_call_name

            if resolved_call_id is None:
                # Mapping not yet available (unexpected); skip emitting unusable delta
                return

            # We have a call id; emit approval or tool-call message accordingly
            if resolved_name and resolved_name in self.requires_approval_tools:
                yield ApprovalRequestMessage(
                    id=decrement_message_uuid(self.letta_message_id),
                    otid=Message.generate_otid_from_id(decrement_message_uuid(self.letta_message_id), -1),
                    date=datetime.now(timezone.utc),
                    tool_call=ToolCallDelta(
                        name=None,
                        arguments=delta,
                        tool_call_id=resolved_call_id,
                    ),
                    run_id=self.run_id,
                    step_id=self.step_id,
                )
            else:
                if prev_message_type and prev_message_type != "tool_call_message":
                    message_index += 1
                tool_call_delta = ToolCallDelta(
                    name=None,
                    arguments=delta,
                    tool_call_id=resolved_call_id,
                )
                yield ToolCallMessage(
                    id=self.letta_message_id,
                    otid=Message.generate_otid_from_id(self.letta_message_id, message_index),
                    date=datetime.now(timezone.utc),
                    tool_call=tool_call_delta,
                    tool_calls=tool_call_delta,
                    run_id=self.run_id,
                    step_id=self.step_id,
                )
                prev_message_type = "tool_call_message"

        # Function calls
        elif isinstance(event, ResponseFunctionCallArgumentsDoneEvent):
            # NOTE: inclusive
            full_args = event.arguments
            return

        # Generic
        elif isinstance(event, ResponseOutputItemDoneEvent):
            # Inclusive, so skip
            return

        # Generic finish
        elif isinstance(event, ResponseCompletedEvent):
            # NOTE we can "rebuild" the final state of the stream using the values in here, instead of relying on the accumulators
            self.final_response = event.response
            self.model = event.response.model
            self.input_tokens = event.response.usage.input_tokens
            self.output_tokens = event.response.usage.output_tokens
            self.message_id = event.response.id
            # Store raw usage for transparent provider trace logging
            try:
                self.raw_usage = event.response.usage.model_dump(exclude_none=True)
            except Exception as e:
                logger.error(f"Failed to capture raw_usage from OpenAI Responses API: {e}")
                self.raw_usage = None
            # Capture cache token details (Responses API uses input_tokens_details)
            # Use `is not None` to capture 0 values (meaning "provider reported 0 cached tokens")
            if hasattr(event.response.usage, "input_tokens_details") and event.response.usage.input_tokens_details:
                details = event.response.usage.input_tokens_details
                if hasattr(details, "cached_tokens") and details.cached_tokens is not None:
                    self.cached_tokens = details.cached_tokens
            # Capture reasoning token details (Responses API uses output_tokens_details)
            # Use `is not None` to capture 0 values (meaning "provider reported 0 reasoning tokens")
            if hasattr(event.response.usage, "output_tokens_details") and event.response.usage.output_tokens_details:
                details = event.response.usage.output_tokens_details
                if hasattr(details, "reasoning_tokens") and details.reasoning_tokens is not None:
                    self.reasoning_tokens = details.reasoning_tokens
            return

        else:
            event_type = type(event).__name__
            logger.warning(f"Unhandled event type: {event_type}. Event details: {event if hasattr(event, '__dict__') else str(event)}")
            # Check if this is an error event we should handle
            if hasattr(event, "error") and event.error is not None:
                logger.error(f"Stream error event received: {event.error}")
            return


"""
ResponseCreatedEvent(response=Response(id='resp_0ad9f0876b2555790068c7b783d17c8192a1a12ecc0b83d381', created_at=1757919107.0, error=None, incomplete_details=None, instructions=None, metadata={}, model='gpt-5-2025-08-07', object='response', output=[], parallel_tool_calls=True, temperature=1.0, tool_choice='auto', tools=[], top_p=1.0, background=False, max_output_tokens=None, max_tool_calls=None, previous_response_id=None, prompt=None, prompt_cache_key=None, reasoning=Reasoning(effort='high', generate_summary=None, summary='detailed'), safety_identifier=None, service_tier='auto', status='in_progress', text=ResponseTextConfig(format=ResponseFormatText(type='text'), verbosity='medium'), top_logprobs=0, truncation='disabled', usage=None, user=None, store=True), sequence_number=0, type='response.created')
ResponseInProgressEvent(response=Response(id='resp_0ad9f0876b2555790068c7b783d17c8192a1a12ecc0b83d381', created_at=1757919107.0, error=None, incomplete_details=None, instructions=None, metadata={}, model='gpt-5-2025-08-07', object='response', output=[], parallel_tool_calls=True, temperature=1.0, tool_choice='auto', tools=[], top_p=1.0, background=False, max_output_tokens=None, max_tool_calls=None, previous_response_id=None, prompt=None, prompt_cache_key=None, reasoning=Reasoning(effort='high', generate_summary=None, summary='detailed'), safety_identifier=None, service_tier='auto', status='in_progress', text=ResponseTextConfig(format=ResponseFormatText(type='text'), verbosity='medium'), top_logprobs=0, truncation='disabled', usage=None, user=None, store=True), sequence_number=1, type='response.in_progress')
ResponseOutputItemAddedEvent(item=ResponseReasoningItem(id='rs_0ad9f0876b2555790068c7b78439888192a40c50a09625bb26', summary=[], type='reasoning', content=None, encrypted_content='gAAAAABox7eEiOVncSJVTjHrczwPKD0bueuhRmgzj6sBTQPnyB5TTE4T3CCoxXALshB1mkOnz48dkd8OkkqFSjZ90OmFi1uVZ9LdJQxoibXj2qUetqhwO_Lm8tcy5Yi4DHrqqhMPbGnDOuJr38PyI_Jx5BDPzJlPbDeU6a99Eg531W7nfSVCzwihekQxlcV9X0xYAvSaigCgbu75sSkx4mopcYDeBTxTjYtpJIAH4C-ygv_MyEeqTJqGdGoQ1NjmF6QJECIXir6llkHlvUHhGeAH6bUabUw7SDBk7gJnMAwDUOZVfp0GyWHRVbDfLCrP7G5nkz98iaEl9LFOcTolsrqxYI_e7k2rIejhfvvSEwgvhCOidNjjKNr3Jujt2ALJ6kGgG3fyWu81cLMobRTL6H0iQ2uT8u9XqZ2eiwHwImexRytC1sSDPK9LaBih46J66HVBKQTeRqMA7m379U8o-qLESN6AiS0PoiJvBpT3F89qJSl3rG19NwzJpPC99Ni1Dzgbr6VPqVmYBqJ5pRt98P-zcW4G72xNr1BLWgCGlCiuuNOxvn2fxPmdHt6S4422oNYb8mNkKeL7p0-6QB9C6L4WPrXUmCOr2_9-dcd1YIplHNQd7BGcbrotZIOj_kTgOvkbQa72ihDV6lNFg8w0_WO2JqubjxP4Ss22-hhtODP6dtuhWjAX5vhIS1j0lFlCRjnQsdC6j7nWhq8ymoPVrmoTE9Ej-evsvTnKO1QVXDKPrKd0y-fMmuvMghHCmhqJ5IiYT1xPX6X83HEXwZs2YY5aHHZkKcbgScAhcv0d1Rv4dp18XHzHUkM=', status=None), output_index=0, sequence_number=2, type='response.output_item.added')
ResponseReasoningSummaryPartAddedEvent(item_id='rs_0ad9f0876b2555790068c7b78439888192a40c50a09625bb26', output_index=0, part=Part(text='', type='summary_text'), sequence_number=3, summary_index=0, type='response.reasoning_summary_part.added')
ResponseReasoningSummaryTextDeltaEvent(delta='**Analy', item_id='rs_0ad9f0876b2555790068c7b78439888192a40c50a09625bb26', output_index=0, sequence_number=4, summary_index=0, type='response.reasoning_summary_text.delta', obfuscation='JdVJEL6G1')
ResponseReasoningSummaryTextDeltaEvent(delta='zing', item_id='rs_0ad9f0876b2555790068c7b78439888192a40c50a09625bb26', output_index=0, sequence_number=5, summary_index=0, type='response.reasoning_summary_text.delta', obfuscation='3g4DefV5mIyG')
ResponseReasoningSummaryTextDeltaEvent(delta=' r', item_id='rs_0ad9f0876b2555790068c7b78439888192a40c50a09625bb26', output_index=0, sequence_number=6, summary_index=0, type='response.reasoning_summary_text.delta', obfuscation='dCErh1m4eFG18w')
ResponseReasoningSummaryTextDeltaEvent(delta=' things', item_id='rs_0ad9f0876b2555790068c7b78439888192a40c50a09625bb26', output_index=0, sequence_number=214, summary_index=1, type='response.reasoning_summary_text.delta', obfuscation='hPD6t2pv9')
ResponseReasoningSummaryTextDeltaEvent(delta='!', item_id='rs_0ad9f0876b2555790068c7b78439888192a40c50a09625bb26', output_index=0, sequence_number=215, summary_index=1, type='response.reasoning_summary_text.delta', obfuscation='g1Sjo96fgHE4LQa')
ResponseReasoningSummaryTextDoneEvent(item_id='rs_0ad9f0876b2555790068c7b78439888192a40c50a09625bb26', output_index=0, sequence_number=216, summary_index=1, text='**Clarifying letter counts**\n\nI realize this task is straightforward: I can provide both answers. If the user is counting uppercase R\'s, the answer would be 0. For a case-insensitive count, it\'s 3. It\'s good to give both for clarity. I should keep it brief; a concise response would be: "If you\'re asking about uppercase \'R\', there are 0. If counting \'r\' regardless of case, there are 3." This way, I cover all bases without overcomplicating things!', type='response.reasoning_summary_text.done')
ResponseReasoningSummaryPartDoneEvent(item_id='rs_0ad9f0876b2555790068c7b78439888192a40c50a09625bb26', output_index=0, part=Part(text='**Clarifying letter counts**\n\nI realize this task is straightforward: I can provide both answers. If the user is counting uppercase R\'s, the answer would be 0. For a case-insensitive count, it\'s 3. It\'s good to give both for clarity. I should keep it brief; a concise response would be: "If you\'re asking about uppercase \'R\', there are 0. If counting \'r\' regardless of case, there are 3." This way, I cover all bases without overcomplicating things!', type='summary_text'), sequence_number=217, summary_index=1, type='response.reasoning_summary_part.done')
ResponseOutputItemDoneEvent(item=ResponseReasoningItem(id='rs_0ad9f0876b2555790068c7b78439888192a40c50a09625bb26', summary=[Summary(text='**Analyzing riddle ambiguity**\n\nI’m thinking about a puzzle that mixes cases to mislead, but the answer should be \'3\'. There are gotcha riddles about counting letters, like asking how many R\'s are in "Strawberry." If it\'s capitalized, the answer differs. The typical trick is that there are no capital R\'s in "strawberry." Since the user asked about uppercase R\'s but quoted the lowercase version, it\'s confusing. I should clarify if they mean uppercase \'R\' or any \'r\'.', type='summary_text'), Summary(text='**Clarifying letter counts**\n\nI realize this task is straightforward: I can provide both answers. If the user is counting uppercase R\'s, the answer would be 0. For a case-insensitive count, it\'s 3. It\'s good to give both for clarity. I should keep it brief; a concise response would be: "If you\'re asking about uppercase \'R\', there are 0. If counting \'r\' regardless of case, there are 3." This way, I cover all bases without overcomplicating things!', type='summary_text')], type='reasoning', content=None, encrypted_content='gAAAAABox7eQs7K1F8qaKB_jhBgufrTLqEXk96f-M9YyeTQ7tvQO730WOtTZtmuQ7XLiAekqxt4yrNQEmgYZhS7qQx-5oq30NlfHezcgkYqmvBqFhGtJkg_Ea6eO9WVMYaXK6nbxXvyK-HS73GvF8AN6NE72rITUE0fdlT6_VeU_OLBSDtVJXUMqbr6V4MOllzXRklbIOJCemZWRax0tenrxaVBrR4IbGoXoFbz5q2Lt8-Xc4NtuUShrzv8AU8Lm46KGvZeX2bWtS0d7-x3in6HJNk4gAFmepYh-cNbk_Qd8UVMvARb2nBjK7jHTB6IP1fDbVYYMUvX6ox8q2jPdHA7ZFRF-YFDXUyX6lwvhLGhVodqyQ4IdmZv1sJ78mvLUpuEdJrHSapA83SN6oaqpoD5cO174UKxyZnrhwQCyxPQ__lS5ZaUgnsIfgtuF5_cKATDxJFBrVo-0SwPHJZdtiCD1CYaVgUKr6uBDtUk32WCDOSJbFK5ClYM1W41x7mBLUWwBJVJ4PZVz3Cc6lR6EMa4a3SAMtIRzMY3869ox6WwDUV8TAYpSMdsb_VW3aezj0hXhnGYUrfmrmtYJEmxy36kV9GsHoBSLwXwNYbjTnP-Pni_AqlCQgZWKTI9KzJ8Zi95l617XwDJ6PzaHt2D6OSX2pmiVPwMGjZDIR6o21fBw3ZwI9TGkJitwL5O9Xlc6PQfYnk-oAVt17OZet6tXQe8LA3wq-9BQXY-88OQRrIGsnFjuGKOmaEXXDmaT1u9lGwOfSdKtU-4X67iDmy5e--lKYZrbWEVy2aoMcwMh2gTsPl-nS_fLzPdOlIgXv4DKCFf_E93LjjdyVoSFctm928rqY_qayqvP5kGx4UjPGiIxFD7tI3lEGMMFA8P0h6nE6NnZgb7pgMtgsqF17SdBKAXFLF8JtuaZulzoBdJJ_2Skq0FO7X8xynq_hhIDdwK2QU9PEfaX7h0j-kGYwVuWs8C_zispG--pHveDqPE1j9GUVrRN9W72-qNHnXRMPEDan1jq4WFN4VknDVwbnK9HR_suKJOTKGZF0MJACtaL4_FyvGfqANLky3cfWeMLpYmXec2Buo-4x8XwlRASCyvK6KXnz7K-M0SuvtoEqTBw0Pa4PBO683OtssZ-ujqMgnzFy3tTKpAabGq-Tz3Dn5fxbYgZONpE6jdTEQxBhkkvplReda3GATlskQHrQtn5Q_tvYwOIQu3iFiP9uoTtfCVQ_Tm4CIGxcEDqWnVaP1fOe8LKHwCvPf7bm046YI3oL-2do70oBJEch0JRKiI3ijrqHzXpI6e-bam9inNnzKxq0HMornRJh37HMDtME0nbXvrNSTu7k7pldDJtQ7SVIoey_PnLirAL9WdfM0HTdsAVmHgXp8u6Ta3_aob-vdrYs19TnGAh6Hp5DqC47wrDeg4RqqSWTM5PLdj4kfdmzkBB90zLMTdR_7Xq7ox64NXfaOXkyLSdFNgz3vmMGyyI3RDeDfVN8tLWfmAWKnooXp866vmdkdWp2IGiq8VWFOe20oaugm8CtT54XLlL6Hh_nipMZy_4pLTVZSsSNd1lvUn-xPMu7WD3NMEdk5b61juYsa77CLHj71vzbPVfHhmOtxqQ_Iqeh4sgPhY0FKRhblvs6yIXy__Ab9MKMYz1Cba1qAr-m9_JGNR1PzUPb7CfS-gbwBwqGoNy5ig1ir-GccsA9hB0UPORaobOGkklDI6B-aEjf8DkzEGdzXQLpJkWwv4cjJAeU1oA9R0hNAwR_STZDvmjkos7j0opRUl-qOez4pBeoRcR8T6V3uqO6OD4j0WNMkLekAGi_BE9tt25v2ClWVSeBE7M9TjlG4uOJwp_IHJZRM3VwunJt9L6ZXALck5sEdIG1EYiAgSophCMqfqUUS2cG7QkDOH-N_jGQisoKRqWJKouERgIHT9TK5ZDeL3WVQL3a-6-HH3y-Lv8UJC1-F_V15FZTgAK3SxUqeHHts6EvDKEqde9QxxTPWwhMOk6dBxNQ0jxfKn9pzNNXhasVIHnk5zn1wWJkm8P3B5sG6Oxwpsxu6ywbY4AOFjBRwHGnnO06CykNaB6uR3KxIlDo2pdidOChI1uZrqYAEDKhjGHcKUQOlgq83wz4dLciiioDYPHfexfSl91QQaQZWrAIN77AbT6e9wxXaZZNQ4Jwo9JpQNjRkoBu2_4tW317nzLj31ayK-5w07imhOBh3ziD8yx3MC7AxuIbsAWo_scZgq8h7OxwRBih9NyiYMePLTLPOPahjDQvl-4XFj4NVNNnXKsiLrxPwtxmMREZraJxcmrSzDFiYDnqkibHXQ3eYyykcjCY3kWRCszoAEYhI3a2qsfbyePgPlfynf3_8rCsb2qaiXmu93lLqrRRg0ktRXtBb3lJVlpVGezUD6Itc_BDZQJAfC0PJbf_AoLfxIVw9-Pj5p5ssxuyybJn0thiqR5CnzcK_TO4jA2PJkjdfK5zLZbyNSYp4NKUpaL1u0jxiuD_vJ30qt3hJugsTv8EvCLdtoNwuvBwjhqplPPZ8_TWCVsowYm3n9LEYWCK-EEk6D2H4_Z8gQYNWz0O735CSiAVpSZpChBRwkfOhlerp8o6k8NJmf7VEqVCE5_iwrKqllB0o8hNLPDSlzQ97EacKz6wsLBorlqTRvGvRrJqwQHwybQLkJlCinqZV9XF52kc0c9GqdKdF-aPxv5VNoPenEBDo6EpAnDyM-TRxzsWtQ71kzRQgLIi-tvO9fTA2MExrF4tv_m1CULjF2jIoeG8RZPC4zhHVd9lvyflhCVSLflF6GR2qzSQua2zqqMsfM4qYGdW83in2U5KDWc7yD7FVi_IM5F1_AKeUaPQ_9MbwCkUO8zdDSQ-eVxY051PGiKHNKTP982Legft29skJqqDZv57Oju9wtI9PmmoeozaBPv4-spuuczsMsVbl6aRLs8xQsPQoke-MUMuelF1kGIqJnMktKiN8AGB8CoU_XzBjGSV-8yJj7tCBYquF66tj5wyn5tsVWwHsi8sl-IRMrVsza1LY0mVx-6ljo97j3WME1LuCTTNF5GOZMHUfRUXgHW5aENuENS9LhsqymVK8sAeQVMVVijC1Gnq2I0ddKLwodsrzCReaqLKx4y3Q4NB0Rom76UzyODd3vzDxjUS9k-IvRbzyXYC0YO-WsngpJr8sKZ8eQqJuBSE3rjT6CEx6-Ldxf8ad-iT6rh-nJRMn27jtHaUgQdZoexMDS1yons8r-MfUYayTaAGeIiimpuCj1A-f3zpQgqqehRkxoEJmjcGLe0oRI5H-kXEk8_LZt45nCiD86HnSCBqRasFNV0lAhWy2UF2cuu0AQuixUDRRgJU5ilWuDTcnJAo-Y4T7wh06xUGuCa50mLAszVnldO-JFrYGYE5UsWTe7qSNOSNsLIJqVoR4WLJJp-FaDFpiir14v1llvh1OumR03aDCA4gOQzeFNzfkUIQNRq0sU1ReZcxLUnlNjHWFqSBfB53rerSV8mdauA91EweO3cOJ1iTUFnAST_QPB2da03hINiRWd8jSkkiUdha-t6iajgOA2w_YlP2cyZ2b-L-cVhBFx0r1VSHocASSSTK1vU1vrPwtXJdMHq6c_EcMSirybtLzpIM3WR-z1wbr2gYvPF2KR_DvsybXE3DsX4qKInsykvBLmg-0RYWcFivmBgAGcIgYLjuCaWbpi5wYi_hNbPBJw07WpxN4QOS9_CaOn0AQh0NnqgPg9DH_am9mpOutvWMKWOqMcNKaRACDCpQkGDhX8yfF6W4EihLKam0vmiYYYtnFQ19Xl59cXf8gVcbNOnElOuA3gK_4PMCYHL66tPUdhKreBlboULKLm0xgYMf3lRrPh803TG0x5L0oYAGzXcGUZIs0AtX2wmkfYSSivFsqSThLY-q2VHtiNBigEZRIWr1lfNzLFYzNipiajvFAfB1EpDpfRkjnnoV5n656y11uFcyySyiskKxZqZryqfb3HPfn8VlK3baKLMk5a0i1CZp5LswGErlk2qgwaSYSWOcHmt6z1GfJOKzrGkHFTWMzzg', status=None), output_index=0, sequence_number=218, type='response.output_item.done')
ResponseOutputItemAddedEvent(item=ResponseOutputMessage(id='msg_0ad9f0876b2555790068c7b790e5388192aa7d4d442882790a', content=[], role='assistant', status='in_progress', type='message'), output_index=1, sequence_number=219, type='response.output_item.added')
ResponseContentPartAddedEvent(content_index=0, item_id='msg_0ad9f0876b2555790068c7b790e5388192aa7d4d442882790a', output_index=1, part=ResponseOutputText(annotations=[], text='', type='output_text', logprobs=[]), sequence_number=220, type='response.content_part.added')
ResponseTextDeltaEvent(content_index=0, delta='Upper', item_id='msg_0ad9f0876b2555790068c7b790e5388192aa7d4d442882790a', logprobs=[], output_index=1, sequence_number=221, type='response.output_text.delta', obfuscation='a8XGRatycGS')
esponseTextDeltaEvent(content_index=0, delta=' ', item_id='msg_0ad9f0876b2555790068c7b790e5388192aa7d4d442882790a', logprobs=[], output_index=1, sequence_number=234, type='response.output_text.delta', obfuscation='Ljhu9qR46fiOkfr')
...
ResponseTextDeltaEvent(content_index=0, delta='3', item_id='msg_0ad9f0876b2555790068c7b790e5388192aa7d4d442882790a', logprobs=[], output_index=1, sequence_number=235, type='response.output_text.delta', obfuscation='5auIEi4JmSFDF72')
ResponseTextDeltaEvent(content_index=0, delta='.', item_id='msg_0ad9f0876b2555790068c7b790e5388192aa7d4d442882790a', logprobs=[], output_index=1, sequence_number=236, type='response.output_text.delta', obfuscation='I78DIGKqtD2P6H2')
ResponseTextDoneEvent(content_index=0, item_id='msg_0ad9f0876b2555790068c7b790e5388192aa7d4d442882790a', logprobs=[], output_index=1, sequence_number=237, text='Uppercase R: 0. Counting r regardless of case: 3.', type='response.output_text.done')
ResponseContentPartDoneEvent(content_index=0, item_id='msg_0ad9f0876b2555790068c7b790e5388192aa7d4d442882790a', output_index=1, part=ResponseOutputText(annotations=[], text='Uppercase R: 0. Counting r regardless of case: 3.', type='output_text', logprobs=[]), sequence_number=238, type='response.content_part.done')
ResponseOutputItemDoneEvent(item=ResponseOutputMessage(id='msg_0ad9f0876b2555790068c7b790e5388192aa7d4d442882790a', content=[ResponseOutputText(annotations=[], text='Uppercase R: 0. Counting r regardless of case: 3.', type='output_text', logprobs=[])], role='assistant', status='completed', type='message'), output_index=1, sequence_number=239, type='response.output_item.done')
ResponseCompletedEvent(response=Response(id='resp_0ad9f0876b2555790068c7b783d17c8192a1a12ecc0b83d381', created_at=1757919107.0, error=None, incomplete_details=None, instructions=None, metadata={}, model='gpt-5-2025-08-07', object='response', output=[ResponseReasoningItem(id='rs_0ad9f0876b2555790068c7b78439888192a40c50a09625bb26', summary=[Summary(text='**Analyzing riddle ambiguity**\n\nI’m thinking about a puzzle that mixes cases to mislead, but the answer should be \'3\'. There are gotcha riddles about counting letters, like asking how many R\'s are in "Strawberry." If it\'s capitalized, the answer differs. The typical trick is that there are no capital R\'s in "strawberry." Since the user asked about uppercase R\'s but quoted the lowercase version, it\'s confusing. I should clarify if they mean uppercase \'R\' or any \'r\'.', type='summary_text'), Summary(text='**Clarifying letter counts**\n\nI realize this task is straightforward: I can provide both answers. If the user is counting uppercase R\'s, the answer would be 0. For a case-insensitive count, it\'s 3. It\'s good to give both for clarity. I should keep it brief; a concise response would be: "If you\'re asking about uppercase \'R\', there are 0. If counting \'r\' regardless of case, there are 3." This way, I cover all bases without overcomplicating things!', type='summary_text')], type='reasoning', content=None, encrypted_content='gAAAAABox7eRIRNnSmrunATD6UBi-Hm77E5JggsaXTKrNH-6ZkwIcosPQPf4vVdjR3ywdcYr4pr2Od3C0ADYSUpyR35tyusZq8A8yR-EmpgA-7otyIGLk5zzZy3AqKv2zZElkvgcr8PEKpYpC8VS6AO4Qg3g_gvBD8eV8j2O_FtGTIQ5MKS_Q0_gf9BCJtkh-PgYjL-0bEXsmCfgPa37BogC4nYh42b5hc7vge3ZH_RmR3irxWontsGaUIkOxR8_oK3RGKvkLfR24QYd4U8BIiZk3G58cR1UDRmtvfHwM4E7W6mpog-dFe9D-V96q1OWBGsNObyHxJcoSNGLxHkxWRvGnq3aWts_Lh-srgJ50rIa19pnOzfXePfdNxdXy7dYXD0D1uiBibpX5nneKUr1C0QmQdwS_nW16pr1oNKZ2fVkZJDTn31rOR3WfvtY9gL7tKo_CMnJ8jT3YKhZxFHG9PhHEoA5OsE_QC-3To54meckPExJqrVJ-h3u_5S4lHK9xu8buzIv4WM92X91zeX98A3g_YkqqvoTUmkFyMoIr8PVxM6Cmg4JtooT9bL2FAVUo6MV2_tlX07hNNH-hWSgqZHMVdx3_cTDAfKW3cAbwaG16ApgK_VUUc7rIfygHxgxtW-YeZpbETlvdNrDIDhzhuPQqPB86DQFh9O262o3cvBHok7V0WVqq-KXH5mH-eio7MhZJ46Ri4qklU9Xn77Tw4zl1cw029FuDKwF0_KsFZ8Omayi5iWJoZFjzqhATR_qt2J3nr368skIHDQ1tSa1vUAJt4UM7A4Un9KG2syCydoAmVQYoRgc5niiWU9FFouzulKW_cfyLrJDlVN1EfaUx2xVzaJO-LhdimhDiP4CKk5DsvEuuhTDn9RkO19cz7eJdrt_wGthYRlcJ-5bSFsSG1UV4VlovcLjuqApc5Fsis9kRo0jkar53HM7rmI7t9uN3TcTCQWGpbDvi-OQblbdvNFZh8wy-BaC0SFtOwcVkhwR2CDCf-7FuB5HOJnzmSOtKDZoFrA9gspNZjXoV6LCKmKIGj_tRLaI9jsn9iZZ7Bdtv2SLw7blE53f4OesXbsC0evl9GzlJfIsiaO1I5pEGCT2sWitWyHrbQLJTWeUBi6SoeULpujVp_w25xJonbCD9HAV51bD6rmAI9LEj0bYOBJ1RmtESAqZpV2wj68i-tv5ejdQ-YXOXSuy4DwInYsALmGMRhFFf0tKhNLHMVdCOij0zo4fU24EhmfxMRZifapm4fDBe2bswE10_LJI2DhzLv_NwQfHMQ0qEDOZQss74qaggBnsr4N-OK6egO3RJYCFddDFUa9vwxYIBHjlqb2p7tX4YpugHQ0ZmDYpUAwRzUmcwYaLjs9lzskQzzpOCeKXmwksWWOax-aWkkw9ic17PTAqne84_LMSNnY4mPOYU4sQ0DxdfNX_2iGVrWSkP3XcLUut1OH6Mah-yWaioJbLoXIpxbngW-IAm3Uxafha94fOHSaMymRYG8ZIbKHvg6n3tud08gBfiiJON5CLCovoKkAeGC3-NQQC58341osMVKSRF6SEpsHMGd97lMdWTlkB3v29m-xf8nuCOqgk4Ig5gIodter_BWs2BEXLiw5ISDBvdl26FVUUoBOpexXFwf99wTroDPK85UYlH5W9m51FlSwfgm0Vg5N9nzivMGClDy_jvNDyI5UHnQjVuqnTAcK0nF6RJn-lnO6hT60qq9hRsqa84iUMqOmQZxXv1KbS0exoqfrqps6ILqifM93r87HVzrrCShWFB1A7hfJHoVqRq-PLsO2iv-V6v9S5_nFwYGG8srrNUuNgzLvLB9J7hlN6fPL4f6vWIJ9sBVpPukR-Pr_I8q8hZicr3YVshIuB544w-srUH4OvRx5v5pz9Jfcm2hHZZjO2yaVDAWKQ_PQk0xj43b-pyrjpAznYdG1QMmFcTfjqVDal97EQeMjIAIjlah0BOqhzHtT0dBjYLyBXZwzO7ii7z-6-jQk5FIDX-RqrdHm8D41dTHx-W7LMvNwpW6ueir7HVoYdIZAP0qaSU-Nf3oJTK8wGhRsh4G3PBsrGbamsfK7c2-AYi_f6kcvXWE4G7ch6c5H6cVqrriil8AcjUZ422dIkFIJHfhbPeAIFy6zuDm9ZnZvgjyqI_mnnK0hlLzfSgJFV6QRAYdkmiviit4qIwEOobM6zYeYPdb09Y15MDLcCOM1KpCecaSJDZm4PrnvP3F0nUpYHvVygA1C-CPenmCjeC_AqWMJ_BVXQyIcVx31fxZCvBIkEskI9Wm6qfJkN8IYw00_X4PnpV-u9d6poChA2smfOsFaeHqoNE_RmPO_QTqHE4m6xBH2RueVnIt4QZ2NVOFyZUI4vBEOsNOXYQpw8tkzONR3FcRRsp2qWNXfmTVdrkVR_-oQpUSlkhQKKo9thNq6SpDezaMUpWjMpi1lgaIZUbSU0WUq3A2EtpWW1yJQjuA2rosQYh2zgILAEtyYgu0Qh5qqsKQB_7oyv3LOB5JHVYa94H1xqHwk9XVfOM6Eeszb1-FYZ3ibagpOiIzPPrGhZA1FIfdVDLk3ulDR7l3-NZZD48SkbkxlnJqbjksgtoM-0AAPVV7q4OSH9MBHK29yVJRahzoFei9toYhD2qN3Mo-HVbWPOo89wJ8LKnwTTF02RUcA4xstjuD5B4IEGF2fMprohnlYVpULejRkkga3Mt6wdjLHzJY4WHkSaGfrDChgMfRpAhtPYQ4sSf4FVFaeT6up-1pU3o-n56zibIwHDfmB_rXEXHLIpaUBEDo7-X8TXZ8SvS-isKwmExJxDtjUI_pglFcThIfigVOJvyemEQ11iLmcoIw6vj5Zge3xzxR7pJgiHbGXhbUpYIJyvrol7NIBZwW_AhgE0WJEjrq9ffdoE9OB311ZZbES2q-ghlfGKgyFrrZNgpY_mYCjd8yx5APWvBYoj-w1WxL42Q0bE3DSyBM9JOwb8t1SPNNduz01MVsbj6_zbya7KDW4pHGiU-4Dh-YU8q9ndeuIezb7km6vQn6zjOfLLPXSkIH99RgAn-eNMPdk5CZWXm16nqgpL1ZtxivXhPItlq2p5akhj64_nreXLe2bKscR7syMZ_9xRC1u9EdomxyuJx6HAB-Jo7_AatJcYeI0BNLiGjnflLnbqwP0jH9_6Q2ucC9oNoNNtiyzq-Wy7zW9Q9eDCL8zVfKVAwNkyvzKSra8EJ6u-ukskCAXmN09_WUXQC00H7foIKOhhn4LXT9LoVgFblMsVjm_bBzXQuEA11Bc3RAJHUyLlpH9K-vz1Zebn-1AUDSlEQENIkzW6TpnoumA1m728tvaF8byNOqKgfRdftIixRHmKYUPrgKXrJErEz6P_n2MJvOvvCVH03o_Dpoh19PY6Rcvv1t56SaUCzdEyTcsVP9JRNh26HckesWjb2IfJsDuGrjlX5V5FabPImAKVRGzwNW5lJLwB59OBGkS4xXxI_vwzFiwrP6Pb2DPVgw3-Epe017D0atbZVs6Oik-14Q9uLrxBz4X2EV0HK_nnkg3mndj2LDBEXtCFky6sIrWer4W3i4Ksrfe5oxGiV02tjNNzFSqHg_z9QX43kTbcBePuYDlMRJ2DwmBykJUXdLcT4j9FlQ9BwOSAKHNaE35j-YZkASDYKqRn5SL9zC71C2qyJVDQ-5cw9GRaFZfLDKO6ySv7yZb367UpQ1uUUzqsyivAYA8jqez7LV0Yxz_hq5mBKE-NdHf-EU9uHHg1zkB73pk1wFOqE5siD0fjr7IkU3R3OcTsNSXEMa63jfeiODcSEoKwcOB8gxG-3Xwh1ueQO6sGvP7Z6sWBfPeWlmA662QytXV7njzFerjuXVRLbCfUg1v26xoPdh2jCKN_GZXroctfpV5LuOGfXd6xjgEpDq4CxNLFmNfVAZBKMQ-Fxk_szAtGpOB3lPcJTdy73VelN_L-adhUGmJmETqqK77CFTYze80l1c_lzWn6zNvS6T5HmLaNFdf5m-Rl_DSEijvJiqZrkY-Ff_R3FthqM4NZDrxwkkX99uXbkEqXjReJ', status=None), ResponseOutputMessage(id='msg_0ad9f0876b2555790068c7b790e5388192aa7d4d442882790a', content=[ResponseOutputText(annotations=[], text='Uppercase R: 0. Counting r regardless of case: 3.', type='output_text', logprobs=[])], role='assistant', status='completed', type='message')], parallel_tool_calls=True, temperature=1.0, tool_choice='auto', tools=[], top_p=1.0, background=False, max_output_tokens=None, max_tool_calls=None, previous_response_id=None, prompt=None, prompt_cache_key=None, reasoning=Reasoning(effort='high', generate_summary=None, summary='detailed'), safety_identifier=None, service_tier='default', status='completed', text=ResponseTextConfig(format=ResponseFormatText(type='text'), verbosity='medium'), top_logprobs=0, truncation='disabled', usage=ResponseUsage(input_tokens=19, input_tokens_details=InputTokensDetails(cached_tokens=0), output_tokens=598, output_tokens_details=OutputTokensDetails(reasoning_tokens=576), total_tokens=617), user=None, store=True), sequence_number=240, type='response.completed')
"""