Drop support for Python 3.9 (#2725)

Co-authored-by: Douwe Maan <[email protected]>

Author: Kludex

.github/workflows/ci.yml

@@ -137,7 +137,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python-version: ["3.9", "3.10", "3.11", "3.12", "3.13"]
+        python-version: ["3.10", "3.11", "3.12", "3.13"]
         install:
           - name: pydantic-ai-slim
             command: "--package pydantic-ai-slim"
@@ -169,7 +169,6 @@ jobs:
 
       - name: store coverage files
         uses: actions/upload-artifact@v4
-        if: matrix.python-version != '3.9'
         with:
           name: coverage-${{ matrix.python-version }}-${{ matrix.install.name }}
           path: .coverage

CLAUDE.md

@@ -91,7 +91,7 @@ This is a uv workspace with multiple packages:
 - **VCR cassettes**: `tests/cassettes/` for recorded LLM API interactions
 - **Test models**: Use `TestModel` for deterministic testing
 - **Examples testing**: `tests/test_examples.py` validates all documentation examples
-- **Multi-version testing**: Python 3.9-3.13 support
+- **Multi-version testing**: Python 3.10-3.13 support
 
 ## Key Configuration Files
 

Makefile

@@ -19,7 +19,6 @@ install: .uv .pre-commit .deno ## Install the package, dependencies, and pre-com
 
 .PHONY: install-all-python
 install-all-python: ## Install and synchronize an interpreter for every python version
-	UV_PROJECT_ENVIRONMENT=.venv39 uv sync --python 3.9 --frozen --all-extras --all-packages --group lint --group docs
 	UV_PROJECT_ENVIRONMENT=.venv310 uv sync --python 3.10 --frozen --all-extras --all-packages --group lint --group docs
 	UV_PROJECT_ENVIRONMENT=.venv311 uv sync --python 3.11 --frozen --all-extras --all-packages --group lint --group docs
 	UV_PROJECT_ENVIRONMENT=.venv312 uv sync --python 3.12 --frozen --all-extras --all-packages --group lint --group docs
@@ -60,13 +59,12 @@ typecheck-both: typecheck-pyright typecheck-mypy
 
 .PHONY: test
 test: ## Run tests and collect coverage data
-	uv run coverage run -m pytest -n auto --dist=loadgroup
+	uv run coverage run -m pytest -n auto --dist=loadgroup --durations=20
 	@uv run coverage combine
 	@uv run coverage report
 
 .PHONY: test-all-python
-test-all-python: ## Run tests on Python 3.9 to 3.13
-	UV_PROJECT_ENVIRONMENT=.venv39 uv run --python 3.9 --all-extras --all-packages coverage run -p -m pytest
+test-all-python: ## Run tests on Python 3.10 to 3.13
 	UV_PROJECT_ENVIRONMENT=.venv310 uv run --python 3.10 --all-extras --all-packages coverage run -p -m pytest
 	UV_PROJECT_ENVIRONMENT=.venv311 uv run --python 3.11 --all-extras --all-packages coverage run -p -m pytest
 	UV_PROJECT_ENVIRONMENT=.venv312 uv run --python 3.12 --all-extras --all-packages coverage run -p -m pytest

clai/pyproject.toml

@@ -28,7 +28,6 @@ classifiers = [
     "Programming Language :: Python",
     "Programming Language :: Python :: 3",
     "Programming Language :: Python :: 3 :: Only",
-    "Programming Language :: Python :: 3.9",
     "Programming Language :: Python :: 3.10",
     "Programming Language :: Python :: 3.11",
     "Programming Language :: Python :: 3.12",
@@ -44,7 +43,7 @@ classifiers = [
     "Topic :: Software Development :: Libraries :: Python Modules",
     "Topic :: Internet",
 ]
-requires-python = ">=3.9"
+requires-python = ">=3.10"
 
 [tool.hatch.metadata.hooks.uv-dynamic-versioning]
 dependencies = [

docs/install.md

@@ -6,7 +6,7 @@ Pydantic AI is available on PyPI as [`pydantic-ai`](https://pypi.org/project/pyd
 pip/uv-add pydantic-ai
 ```
 
-(Requires Python 3.9+)
+(Requires Python 3.10+)
 
 This installs the `pydantic_ai` package, core dependencies, and libraries required to use all the models
 included in Pydantic AI. If you want to use a specific model, you can install the ["slim"](#slim-install) version of Pydantic AI.

examples/pydantic_ai_examples/chat_app.py

@@ -10,14 +10,14 @@
 import asyncio
 import json
 import sqlite3
-from collections.abc import AsyncIterator
+from collections.abc import AsyncIterator, Callable
 from concurrent.futures.thread import ThreadPoolExecutor
 from contextlib import asynccontextmanager
 from dataclasses import dataclass
 from datetime import datetime, timezone
 from functools import partial
 from pathlib import Path
-from typing import Annotated, Any, Callable, Literal, TypeVar
+from typing import Annotated, Any, Literal, TypeVar
 
 import fastapi
 import logfire

examples/pydantic_ai_examples/sql_gen.py

@@ -16,14 +16,13 @@
 from contextlib import asynccontextmanager
 from dataclasses import dataclass
 from datetime import date
-from typing import Annotated, Any, Union
+from typing import Annotated, Any, TypeAlias
 
 import asyncpg
 import logfire
 from annotated_types import MinLen
 from devtools import debug
 from pydantic import BaseModel, Field
-from typing_extensions import TypeAlias
 
 from pydantic_ai import Agent, ModelRetry, RunContext, format_as_xml
 
@@ -91,7 +90,7 @@ class InvalidRequest(BaseModel):
     error_message: str
 
 
-Response: TypeAlias = Union[Success, InvalidRequest]
+Response: TypeAlias = Success | InvalidRequest
 agent = Agent[Deps, Response](
     'google-gla:gemini-1.5-flash',
     # Type ignore while we wait for PEP-0747, nonetheless unions will work fine everywhere else

examples/pyproject.toml

@@ -28,7 +28,6 @@ classifiers = [
     "Programming Language :: Python",
     "Programming Language :: Python :: 3",
     "Programming Language :: Python :: 3 :: Only",
-    "Programming Language :: Python :: 3.9",
     "Programming Language :: Python :: 3.10",
     "Programming Language :: Python :: 3.11",
     "Programming Language :: Python :: 3.12",
@@ -44,7 +43,7 @@ classifiers = [
     "Topic :: Software Development :: Libraries :: Python Modules",
     "Topic :: Internet",
 ]
-requires-python = ">=3.9"
+requires-python = ">=3.10"
 
 [tool.hatch.metadata.hooks.uv-dynamic-versioning]
 dependencies = [
@@ -57,8 +56,8 @@ dependencies = [
     "rich>=13.9.2",
     "uvicorn>=0.32.0",
     "devtools>=0.12.2",
-    "gradio>=5.9.0; python_version>'3.9'",
-    "mcp[cli]>=1.4.1; python_version >= '3.10'",
+    "gradio>=5.9.0",
+    "mcp[cli]>=1.4.1",
     "modal>=1.0.4",
     "duckdb>=1.3.2",
     "datasets>=4.0.0",

pydantic_ai_slim/pydantic_ai/_agent_graph.py

@@ -4,14 +4,14 @@
 import dataclasses
 import hashlib
 from collections import defaultdict, deque
-from collections.abc import AsyncIterator, Awaitable, Iterator, Sequence
+from collections.abc import AsyncIterator, Awaitable, Callable, Iterator, Sequence
 from contextlib import asynccontextmanager, contextmanager
 from contextvars import ContextVar
 from dataclasses import field
-from typing import TYPE_CHECKING, Any, Callable, Generic, Literal, Union, cast
+from typing import TYPE_CHECKING, Any, Generic, Literal, TypeGuard, Union, cast
 
 from opentelemetry.trace import Tracer
-from typing_extensions import TypeGuard, TypeVar, assert_never
+from typing_extensions import TypeVar, assert_never
 
 from pydantic_ai._function_schema import _takes_ctx as is_takes_ctx  # type: ignore
 from pydantic_ai._tool_manager import ToolManager
@@ -59,12 +59,12 @@
 _HistoryProcessorAsyncWithCtx = Callable[
     [RunContext[DepsT], list[_messages.ModelMessage]], Awaitable[list[_messages.ModelMessage]]
 ]
-HistoryProcessor = Union[
-    _HistoryProcessorSync,
-    _HistoryProcessorAsync,
-    _HistoryProcessorSyncWithCtx[DepsT],
-    _HistoryProcessorAsyncWithCtx[DepsT],
-]
+HistoryProcessor = (
+    _HistoryProcessorSync
+    | _HistoryProcessorAsync
+    | _HistoryProcessorSyncWithCtx[DepsT]
+    | _HistoryProcessorAsyncWithCtx[DepsT]
+)
 """A function that processes a list of model messages and returns a list of model messages.
 
 Can optionally accept a `RunContext` as a parameter.
@@ -736,15 +736,15 @@ async def _call_function_tool(
 
     if isinstance(tool_result, _messages.ToolReturn):
         if (
-            isinstance(tool_result.return_value, _messages.MultiModalContentTypes)
+            isinstance(tool_result.return_value, _messages.MultiModalContent)
             or isinstance(tool_result.return_value, list)
             and any(
-                isinstance(content, _messages.MultiModalContentTypes)
+                isinstance(content, _messages.MultiModalContent)
                 for content in tool_result.return_value  # type: ignore
             )
         ):
             raise exceptions.UserError(
-                f'The `return_value` of tool {tool_call.tool_name!r} contains invalid nested `MultiModalContentTypes` objects. '
+                f'The `return_value` of tool {tool_call.tool_name!r} contains invalid nested `MultiModalContent` objects. '
                 f'Please use `content` instead.'
             )
 
@@ -765,7 +765,7 @@ def process_content(content: Any) -> Any:
                     f'The return value of tool {tool_call.tool_name!r} contains invalid nested `ToolReturn` objects. '
                     f'`ToolReturn` should be used directly.'
                 )
-            elif isinstance(content, _messages.MultiModalContentTypes):
+            elif isinstance(content, _messages.MultiModalContent):
                 if isinstance(content, _messages.BinaryContent):
                     identifier = content.identifier or multi_modal_content_identifier(content.data)
                 else:

pydantic_ai_slim/pydantic_ai/_function_schema.py

@@ -5,10 +5,10 @@
 
 from __future__ import annotations as _annotations
 
-from collections.abc import Awaitable
+from collections.abc import Awaitable, Callable
 from dataclasses import dataclass, field
 from inspect import Parameter, signature
-from typing import TYPE_CHECKING, Any, Callable, Union, cast
+from typing import TYPE_CHECKING, Any, Concatenate, cast, get_origin
 
 from pydantic import ConfigDict
 from pydantic._internal import _decorators, _generate_schema, _typing_extra
@@ -17,7 +17,7 @@
 from pydantic.json_schema import GenerateJsonSchema
 from pydantic.plugin._schema_validator import create_schema_validator
 from pydantic_core import SchemaValidator, core_schema
-from typing_extensions import Concatenate, ParamSpec, TypeIs, TypeVar, get_origin
+from typing_extensions import ParamSpec, TypeIs, TypeVar
 
 from ._griffe import doc_descriptions
 from ._run_context import RunContext
@@ -231,7 +231,7 @@ def function_schema(  # noqa: C901
 
 WithCtx = Callable[Concatenate[RunContext[Any], P], R]
 WithoutCtx = Callable[P, R]
-TargetFunc = Union[WithCtx[P, R], WithoutCtx[P, R]]
+TargetFunc = WithCtx[P, R] | WithoutCtx[P, R]
 
 
 def _takes_ctx(function: TargetFunc[P, R]) -> TypeIs[WithCtx[P, R]]: