chore: drop Python 3.9 support across metadata, CI, and docs (#2474)

Author: seratch

.github/workflows/tests.yml

@@ -122,28 +122,3 @@ jobs:
       - name: Skip docs build
         if: steps.changes.outputs.run != 'true'
         run: echo "Skipping docs build for non-docs changes."
-
-  old_version_tests:
-    runs-on: ubuntu-latest
-    env:
-      OPENAI_API_KEY: fake-for-tests
-    steps:
-      - name: Checkout repository
-        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd
-      - name: Detect code changes
-        id: changes
-        run: ./.github/scripts/detect-changes.sh code "${{ github.event.pull_request.base.sha || github.event.before }}" "${{ github.sha }}"
-      - name: Setup uv
-        if: steps.changes.outputs.run == 'true'
-        uses: astral-sh/setup-uv@803947b9bd8e9f986429fa0c5a41c367cd732b41
-        with:
-          enable-cache: true
-      - name: Install dependencies
-        if: steps.changes.outputs.run == 'true'
-        run: make sync
-      - name: Run tests
-        if: steps.changes.outputs.run == 'true'
-        run: make old_version_tests
-      - name: Skip old version tests
-        if: steps.changes.outputs.run != 'true'
-        run: echo "Skipping old version tests for non-code changes."

AGENTS.md

@@ -86,7 +86,7 @@ The OpenAI Agents Python repository provides the Python Agents SDK, examples, an
 
 ### Prerequisites
 
-- Python 3.9+.
+- Python 3.10+.
 - `uv` installed for dependency management (`uv sync`) and `uv run` for Python commands.
 - `make` available to run repository tasks.
 
@@ -172,9 +172,10 @@ make tests
   ```bash
   make sync
   ```
-- Run tests against Python 3.9 in an isolated environment:
+- Run tests against the oldest supported version (Python 3.10) in an isolated environment:
   ```bash
-  make old_version_tests
+  UV_PROJECT_ENVIRONMENT=.venv_310 uv sync --python 3.10 --all-extras --all-packages --group dev
+  UV_PROJECT_ENVIRONMENT=.venv_310 uv run --python 3.10 -m pytest
   ```
 - Documentation workflows:
   ```bash

Makefile

@@ -38,11 +38,6 @@ snapshots-fix:
 snapshots-create: 
 	uv run pytest --inline-snapshot=create 
 
-.PHONY: old_version_tests
-old_version_tests:
-	UV_PROJECT_ENVIRONMENT=.venv_39 uv sync --python 3.9 --all-extras --all-packages --group dev
-	UV_PROJECT_ENVIRONMENT=.venv_39 uv run --python 3.9 -m pytest
-
 .PHONY: build-docs
 build-docs:
 	uv run docs/scripts/generate_ref_files.py

README.md

@@ -19,7 +19,7 @@ Explore the [examples](examples) directory to see the SDK in action, and read ou
 
 ## Get started
 
-To get started, set up your Python environment (Python 3.9 or newer required), and then install OpenAI Agents SDK package.
+To get started, set up your Python environment (Python 3.10 or newer required), and then install OpenAI Agents SDK package.
 
 ### venv
 

docs/realtime/quickstart.md

@@ -7,7 +7,7 @@ Realtime agents are in beta. Expect some breaking changes as we improve the impl
 
 ## Prerequisites
 
--   Python 3.9 or higher
+-   Python 3.10 or higher
 -   OpenAI API key
 -   Basic familiarity with the OpenAI Agents SDK
 

examples/realtime/twilio/README.md

@@ -4,7 +4,7 @@ This example demonstrates how to connect the OpenAI Realtime API to a phone call
 
 ## Prerequisites
 
--   Python 3.9+
+-   Python 3.10+
 -   OpenAI API key with [Realtime API](https://platform.openai.com/docs/guides/realtime) access
 -   [Twilio](https://www.twilio.com/docs/voice) account with a phone number
 -   A tunneling service like [ngrok](https://ngrok.com/) to expose your local server

examples/realtime/twilio_sip/README.md

@@ -4,7 +4,7 @@ This example shows how to handle OpenAI Realtime SIP calls with the Agents SDK.
 
 ## Prerequisites
 
-- Python 3.9+
+- Python 3.10+
 - An OpenAI API key with Realtime API access
 - A configured webhook secret for your OpenAI project
 - A Twilio account with a phone number and Elastic SIP Trunking enabled

pyproject.toml

@@ -3,7 +3,7 @@ name = "openai-agents"
 version = "0.8.4"
 description = "OpenAI Agents SDK"
 readme = "README.md"
-requires-python = ">=3.9"
+requires-python = ">=3.10"
 license = "MIT"
 authors = [{ name = "OpenAI", email = "support@openai.com" }]
 dependencies = [
@@ -19,7 +19,6 @@ classifiers = [
     "Typing :: Typed",
     "Intended Audience :: Developers",
     "Programming Language :: Python :: 3",
-    "Programming Language :: Python :: 3.9",
     "Programming Language :: Python :: 3.10",
     "Programming Language :: Python :: 3.11",
     "Programming Language :: Python :: 3.12",

src/agents/realtime/openai_realtime.py

@@ -247,11 +247,6 @@ async def _build_model_settings_from_agent(
     return updated_settings
 
 
-# Note: Avoid a module-level union alias for Python 3.9 compatibility.
-# Using a union at runtime (e.g., A | B) in a type alias triggers evaluation
-# during import on 3.9. We instead inline the union in annotations below.
-
-
 class TransportConfig(TypedDict):
     """Low-level network transport configuration."""
 

src/agents/realtime/session.py

@@ -320,7 +320,7 @@ async def on_event(self, event: RealtimeModelEvent) -> None:
                     for idx, entry in enumerate(incoming_item.content):
                         # Only attempt to preserve for audio-like content
                         if entry.type in ("audio", "input_audio"):
-                            # Use tuple form for Python 3.9 compatibility
+                            # Use tuple form when checking against multiple classes.
                             assert isinstance(entry, (InputAudio, AssistantAudio))
                             # Determine if transcript is missing/empty on the incoming entry
                             entry_transcript = entry.transcript