Streaming with Semantic Events

Working with the OpenAI Responses API

James Chapman

AI Curriculum Manager, DataCamp

Why Stream?

Semantic Events

Structured updates that describe what's happening

Semantic Events

Structured updates that describe what's happening

Event Type	Description
`response.created`	The model has started generating
`response.output_text.delta`	Partial text update
`response.output_text.done`	Text block complete
`response.function_call.arguments.delta`	Streaming tool arguments
`response.completed`	The entire response is finished

Example: Basic Text Streaming

prompt = "Explain the seasons of the year concisely to a child."


with client.responses.create(model="gpt-5-mini", input=prompt, stream=True) as stream:

    current_text = ""


    for event in stream:
        if event.type == "response.output_text.delta":

            current_text += event.delta
            print(current_text)

Example: Basic Text Streaming

Example: Handling Multiple Events

prompt = "Explain how a neural network learns concisely for a child."

with client.responses.create(model="gpt-5-mini", input=prompt, stream=True) as stream:

    for event in stream:
        if event.type == "response.created":

            print("Response started...\n")


        elif event.type == "response.output_text.done":

            print("\n\n--- Text block finished ---\n")


        elif event.type == "response.completed":

            print(f"\nFull response:\n{current_text}")

Example: Handling Multiple Events

Example: Streaming Tool Events

convert_currency() -> str:

date_time: str
from_timezone: str
to_timezone: str

tools = [
    {
        "type": "function",
        "name": "convert_currency",
        ...
     }
]

Example: Streaming Tool Events

prompt = "How much is 120 euros in British pounds using the current exchange rate?"


with client.responses.create(model="gpt-5-mini", input=prompt, tools=tools, stream=True) as stream:

    current_args = ""

    for event in stream:
        if event.type == "response.function_call_arguments.delta":

            current_args += event.delta
            print("Streaming args:", current_args)

        elif event.type == "response.function_call_arguments.done":

            print("\nFinal arguments:", event.arguments)

        elif event.type == "response.completed":

            print("\n--- Completed ---")

Streaming with Semantic Events

Why Stream?

Why Stream?

Semantic Events

Semantic Events

Example: Basic Text Streaming

Example: Basic Text Streaming

Example: Handling Multiple Events

Example: Handling Multiple Events

Example: Streaming Tool Events

Example: Streaming Tool Events

Example: Streaming Tool Events

Summary

Let's practice!