diff --git a/.github/workflows/python-sdk-tests.yml b/.github/workflows/python-sdk-tests.yml
index 079395b3..941f0818 100644
--- a/.github/workflows/python-sdk-tests.yml
+++ b/.github/workflows/python-sdk-tests.yml
@@ -37,6 +37,8 @@ jobs:
       fail-fast: false
       matrix:
         os: [ubuntu-latest, macos-latest, windows-latest]
+        # Test the oldest supported Python version to make sure compatibility is maintained.
+        python-version: ["3.11"]
     runs-on: ${{ matrix.os }}
     defaults:
       run:
@@ -46,7 +48,7 @@ jobs:
       - uses: actions/checkout@v6.0.2
       - uses: actions/setup-python@v6
         with:
-          python-version: "3.12"
+          python-version: ${{ matrix.python-version }}
       - uses: actions/setup-node@v6
         with:
           node-version: "22"
diff --git a/python/README.md b/python/README.md
index aa82e0c3..3a1c4c73 100644
--- a/python/README.md
+++ b/python/README.md
@@ -401,11 +401,11 @@ async def handle_user_input(request, invocation):
     # request["question"] - The question to ask
     # request.get("choices") - Optional list of choices for multiple choice
     # request.get("allowFreeform", True) - Whether freeform input is allowed
-    
+
     print(f"Agent asks: {request['question']}")
     if request.get("choices"):
         print(f"Choices: {', '.join(request['choices'])}")
-    
+
     # Return the user's response
     return {
         "answer": "User's answer here",
@@ -483,5 +483,5 @@ session = await client.create_session({
 
 ## Requirements
 
-- Python 3.9+
+- Python 3.11+
 - GitHub Copilot CLI installed and accessible
diff --git a/python/copilot/client.py b/python/copilot/client.py
index 88b3d97a..bc231e52 100644
--- a/python/copilot/client.py
+++ b/python/copilot/client.py
@@ -19,9 +19,10 @@
 import subprocess
 import sys
 import threading
+from collections.abc import Callable
 from dataclasses import asdict, is_dataclass
 from pathlib import Path
-from typing import Any, Callable, Optional, cast
+from typing import Any, cast
 
 from .generated.rpc import ServerRpc
 from .generated.session_events import session_event_from_dict
@@ -51,7 +52,7 @@
 )
 
 
-def _get_bundled_cli_path() -> Optional[str]:
+def _get_bundled_cli_path() -> str | None:
     """Get the path to the bundled CLI binary, if available."""
     # The binary is bundled in copilot/bin/ within the package
     bin_dir = Path(__file__).parent / "bin"
@@ -106,7 +107,7 @@ class CopilotClient:
         >>> client = CopilotClient({"cli_url": "localhost:3000"})
     """
 
-    def __init__(self, options: Optional[CopilotClientOptions] = None):
+    def __init__(self, options: CopilotClientOptions | None = None):
         """
         Initialize a new CopilotClient.
 
@@ -151,7 +152,7 @@ def __init__(self, options: Optional[CopilotClientOptions] = None):
         self._is_external_server: bool = False
         if opts.get("cli_url"):
             self._actual_host, actual_port = self._parse_cli_url(opts["cli_url"])
-            self._actual_port: Optional[int] = actual_port
+            self._actual_port: int | None = actual_port
             self._is_external_server = True
         else:
             self._actual_port = None
@@ -197,19 +198,19 @@ def __init__(self, options: Optional[CopilotClientOptions] = None):
         if github_token:
             self.options["github_token"] = github_token
 
-        self._process: Optional[subprocess.Popen] = None
-        self._client: Optional[JsonRpcClient] = None
+        self._process: subprocess.Popen | None = None
+        self._client: JsonRpcClient | None = None
         self._state: ConnectionState = "disconnected"
         self._sessions: dict[str, CopilotSession] = {}
         self._sessions_lock = threading.Lock()
-        self._models_cache: Optional[list[ModelInfo]] = None
+        self._models_cache: list[ModelInfo] | None = None
         self._models_cache_lock = asyncio.Lock()
         self._lifecycle_handlers: list[SessionLifecycleHandler] = []
         self._typed_lifecycle_handlers: dict[
             SessionLifecycleEventType, list[SessionLifecycleHandler]
         ] = {}
         self._lifecycle_handlers_lock = threading.Lock()
-        self._rpc: Optional[ServerRpc] = None
+        self._rpc: ServerRpc | None = None
 
     @property
     def rpc(self) -> ServerRpc:
@@ -786,7 +787,7 @@ def get_state(self) -> ConnectionState:
         """
         return self._state
 
-    async def ping(self, message: Optional[str] = None) -> "PingResponse":
+    async def ping(self, message: str | None = None) -> "PingResponse":
         """
         Send a ping request to the server to verify connectivity.
 
@@ -956,7 +957,7 @@ async def delete_session(self, session_id: str) -> None:
             if session_id in self._sessions:
                 del self._sessions[session_id]
 
-    async def get_foreground_session_id(self) -> Optional[str]:
+    async def get_foreground_session_id(self) -> str | None:
         """
         Get the ID of the session currently displayed in the TUI.
 
@@ -1009,7 +1010,7 @@ async def set_foreground_session_id(self, session_id: str) -> None:
     def on(
         self,
         event_type_or_handler: SessionLifecycleEventType | SessionLifecycleHandler,
-        handler: Optional[SessionLifecycleHandler] = None,
+        handler: SessionLifecycleHandler | None = None,
     ) -> Callable[[], None]:
         """
         Subscribe to session lifecycle events.
@@ -1267,7 +1268,7 @@ async def read_port():
 
         try:
             await asyncio.wait_for(read_port(), timeout=10.0)
-        except asyncio.TimeoutError:
+        except TimeoutError:
             raise RuntimeError("Timeout waiting for CLI server to start")
 
     async def _connect_to_server(self) -> None:
diff --git a/python/copilot/generated/rpc.py b/python/copilot/generated/rpc.py
index 27a2bca2..a557987e 100644
--- a/python/copilot/generated/rpc.py
+++ b/python/copilot/generated/rpc.py
@@ -10,7 +10,8 @@
 
 
 from dataclasses import dataclass
-from typing import Any, Optional, List, Dict, TypeVar, Type, cast, Callable
+from typing import Any, TypeVar, cast
+from collections.abc import Callable
 from enum import Enum
 
 
@@ -52,22 +53,22 @@ def from_bool(x: Any) -> bool:
     return x
 
 
-def to_class(c: Type[T], x: Any) -> dict:
+def to_class(c: type[T], x: Any) -> dict:
     assert isinstance(x, c)
     return cast(Any, x).to_dict()
 
 
-def from_list(f: Callable[[Any], T], x: Any) -> List[T]:
+def from_list(f: Callable[[Any], T], x: Any) -> list[T]:
     assert isinstance(x, list)
     return [f(y) for y in x]
 
 
-def from_dict(f: Callable[[Any], T], x: Any) -> Dict[str, T]:
+def from_dict(f: Callable[[Any], T], x: Any) -> dict[str, T]:
     assert isinstance(x, dict)
     return { k: f(v) for (k, v) in x.items() }
 
 
-def to_enum(c: Type[EnumT], x: Any) -> EnumT:
+def to_enum(c: type[EnumT], x: Any) -> EnumT:
     assert isinstance(x, c)
     return x.value
 
@@ -101,7 +102,7 @@ def to_dict(self) -> dict:
 
 @dataclass
 class PingParams:
-    message: Optional[str] = None
+    message: str | None = None
     """Optional message to echo back"""
 
     @staticmethod
@@ -138,8 +139,8 @@ def to_dict(self) -> dict:
 @dataclass
 class Limits:
     max_context_window_tokens: float
-    max_output_tokens: Optional[float] = None
-    max_prompt_tokens: Optional[float] = None
+    max_output_tokens: float | None = None
+    max_prompt_tokens: float | None = None
 
     @staticmethod
     def from_dict(obj: Any) -> 'Limits':
@@ -233,16 +234,16 @@ class Model:
     name: str
     """Display name"""
 
-    billing: Optional[Billing] = None
+    billing: Billing | None = None
     """Billing information"""
 
-    default_reasoning_effort: Optional[str] = None
+    default_reasoning_effort: str | None = None
     """Default reasoning effort level (only present if model supports reasoning effort)"""
 
-    policy: Optional[Policy] = None
+    policy: Policy | None = None
     """Policy state (if applicable)"""
 
-    supported_reasoning_efforts: Optional[List[str]] = None
+    supported_reasoning_efforts: list[str] | None = None
     """Supported reasoning effort levels (only present if model supports reasoning effort)"""
 
     @staticmethod
@@ -275,7 +276,7 @@ def to_dict(self) -> dict:
 
 @dataclass
 class ModelsListResult:
-    models: List[Model]
+    models: list[Model]
     """List of available models with full metadata"""
 
     @staticmethod
@@ -298,14 +299,14 @@ class Tool:
     name: str
     """Tool identifier (e.g., "bash", "grep", "str_replace_editor")"""
 
-    instructions: Optional[str] = None
+    instructions: str | None = None
     """Optional instructions for how to use this tool effectively"""
 
-    namespaced_name: Optional[str] = None
+    namespaced_name: str | None = None
     """Optional namespaced name for declarative filtering (e.g., "playwright/navigate" for MCP
     tools)
     """
-    parameters: Optional[Dict[str, Any]] = None
+    parameters: dict[str, Any] | None = None
     """JSON Schema for the tool's input parameters"""
 
     @staticmethod
@@ -333,7 +334,7 @@ def to_dict(self) -> dict:
 
 @dataclass
 class ToolsListResult:
-    tools: List[Tool]
+    tools: list[Tool]
     """List of available built-in tools with metadata"""
 
     @staticmethod
@@ -350,7 +351,7 @@ def to_dict(self) -> dict:
 
 @dataclass
 class ToolsListParams:
-    model: Optional[str] = None
+    model: str | None = None
     """Optional model ID — when provided, the returned tool list reflects model-specific
     overrides
     """
@@ -385,7 +386,7 @@ class QuotaSnapshot:
     used_requests: float
     """Number of requests used so far this period"""
 
-    reset_date: Optional[str] = None
+    reset_date: str | None = None
     """Date when the quota resets (ISO 8601)"""
 
     @staticmethod
@@ -413,7 +414,7 @@ def to_dict(self) -> dict:
 
 @dataclass
 class AccountGetQuotaResult:
-    quota_snapshots: Dict[str, QuotaSnapshot]
+    quota_snapshots: dict[str, QuotaSnapshot]
     """Quota snapshots keyed by type (e.g., chat, completions, premium_interactions)"""
 
     @staticmethod
@@ -430,7 +431,7 @@ def to_dict(self) -> dict:
 
 @dataclass
 class SessionModelGetCurrentResult:
-    model_id: Optional[str] = None
+    model_id: str | None = None
 
     @staticmethod
     def from_dict(obj: Any) -> 'SessionModelGetCurrentResult':
@@ -447,7 +448,7 @@ def to_dict(self) -> dict:
 
 @dataclass
 class SessionModelSwitchToResult:
-    model_id: Optional[str] = None
+    model_id: str | None = None
 
     @staticmethod
     def from_dict(obj: Any) -> 'SessionModelSwitchToResult':
@@ -546,7 +547,7 @@ class SessionPlanReadResult:
     exists: bool
     """Whether plan.md exists in the workspace"""
 
-    content: Optional[str] = None
+    content: str | None = None
     """The content of plan.md, or null if it does not exist"""
 
     @staticmethod
@@ -606,7 +607,7 @@ def to_dict(self) -> dict:
 
 @dataclass
 class SessionWorkspaceListFilesResult:
-    files: List[str]
+    files: list[str]
     """Relative file paths in the workspace files directory"""
 
     @staticmethod
@@ -708,7 +709,7 @@ def to_dict(self) -> dict:
 
 @dataclass
 class SessionFleetStartParams:
-    prompt: Optional[str] = None
+    prompt: str | None = None
     """Optional user prompt to combine with fleet instructions"""
 
     @staticmethod
@@ -753,7 +754,7 @@ def to_dict(self) -> dict:
 
 @dataclass
 class SessionAgentListResult:
-    agents: List[AgentElement]
+    agents: list[AgentElement]
     """Available custom agents"""
 
     @staticmethod
@@ -797,7 +798,7 @@ def to_dict(self) -> dict:
 
 @dataclass
 class SessionAgentGetCurrentResult:
-    agent: Optional[SessionAgentGetCurrentResultAgent] = None
+    agent: SessionAgentGetCurrentResultAgent | None = None
     """Currently selected custom agent, or null if using the default agent"""
 
     @staticmethod
diff --git a/python/copilot/generated/session_events.py b/python/copilot/generated/session_events.py
index 3a201ba0..0166fc63 100644
--- a/python/copilot/generated/session_events.py
+++ b/python/copilot/generated/session_events.py
@@ -5,7 +5,8 @@
 
 from enum import Enum
 from dataclasses import dataclass
-from typing import Any, Optional, List, Dict, Union, TypeVar, Type, cast, Callable
+from typing import Any, TypeVar, cast
+from collections.abc import Callable
 from datetime import datetime
 from uuid import UUID
 import dateutil.parser
@@ -25,7 +26,7 @@ def to_float(x: Any) -> float:
     return x
 
 
-def to_class(c: Type[T], x: Any) -> dict:
+def to_class(c: type[T], x: Any) -> dict:
     assert isinstance(x, c)
     return cast(Any, x).to_dict()
 
@@ -49,17 +50,17 @@ def from_union(fs, x):
     assert False
 
 
-def to_enum(c: Type[EnumT], x: Any) -> EnumT:
+def to_enum(c: type[EnumT], x: Any) -> EnumT:
     assert isinstance(x, c)
     return x.value
 
 
-def from_list(f: Callable[[Any], T], x: Any) -> List[T]:
+def from_list(f: Callable[[Any], T], x: Any) -> list[T]:
     assert isinstance(x, list)
     return [f(y) for y in x]
 
 
-def from_dict(f: Callable[[Any], T], x: Any) -> Dict[str, T]:
+def from_dict(f: Callable[[Any], T], x: Any) -> dict[str, T]:
     assert isinstance(x, dict)
     return { k: f(v) for (k, v) in x.items() }
 
@@ -171,11 +172,11 @@ class AttachmentType(Enum):
 class Attachment:
     display_name: str
     type: AttachmentType
-    line_range: Optional[LineRange] = None
-    path: Optional[str] = None
-    file_path: Optional[str] = None
-    selection: Optional[Selection] = None
-    text: Optional[str] = None
+    line_range: LineRange | None = None
+    path: str | None = None
+    file_path: str | None = None
+    selection: Selection | None = None
+    text: str | None = None
 
     @staticmethod
     def from_dict(obj: Any) -> 'Attachment':
@@ -208,7 +209,7 @@ def to_dict(self) -> dict:
 
 @dataclass
 class CodeChanges:
-    files_modified: List[str]
+    files_modified: list[str]
     lines_added: float
     lines_removed: float
 
@@ -253,9 +254,9 @@ def to_dict(self) -> dict:
 @dataclass
 class ContextClass:
     cwd: str
-    branch: Optional[str] = None
-    git_root: Optional[str] = None
-    repository: Optional[str] = None
+    branch: str | None = None
+    git_root: str | None = None
+    repository: str | None = None
 
     @staticmethod
     def from_dict(obj: Any) -> 'ContextClass':
@@ -281,8 +282,8 @@ def to_dict(self) -> dict:
 @dataclass
 class ErrorClass:
     message: str
-    code: Optional[str] = None
-    stack: Optional[str] = None
+    code: str | None = None
+    stack: str | None = None
 
     @staticmethod
     def from_dict(obj: Any) -> 'ErrorClass':
@@ -304,8 +305,8 @@ def to_dict(self) -> dict:
 
 @dataclass
 class Metadata:
-    prompt_version: Optional[str] = None
-    variables: Optional[Dict[str, Any]] = None
+    prompt_version: str | None = None
+    variables: dict[str, Any] | None = None
 
     @staticmethod
     def from_dict(obj: Any) -> 'Metadata':
@@ -401,7 +402,7 @@ class QuotaSnapshot:
     remaining_percentage: float
     usage_allowed_with_exhausted_quota: bool
     used_requests: float
-    reset_date: Optional[datetime] = None
+    reset_date: datetime | None = None
 
     @staticmethod
     def from_dict(obj: Any) -> 'QuotaSnapshot':
@@ -434,7 +435,7 @@ def to_dict(self) -> dict:
 class RepositoryClass:
     name: str
     owner: str
-    branch: Optional[str] = None
+    branch: str | None = None
 
     @staticmethod
     def from_dict(obj: Any) -> 'RepositoryClass':
@@ -461,9 +462,9 @@ class Theme(Enum):
 @dataclass
 class Icon:
     src: str
-    mime_type: Optional[str] = None
-    sizes: Optional[List[str]] = None
-    theme: Optional[Theme] = None
+    mime_type: str | None = None
+    sizes: list[str] | None = None
+    theme: Theme | None = None
 
     @staticmethod
     def from_dict(obj: Any) -> 'Icon':
@@ -489,9 +490,9 @@ def to_dict(self) -> dict:
 @dataclass
 class Resource:
     uri: str
-    mime_type: Optional[str] = None
-    text: Optional[str] = None
-    blob: Optional[str] = None
+    mime_type: str | None = None
+    text: str | None = None
+    blob: str | None = None
 
     @staticmethod
     def from_dict(obj: Any) -> 'Resource':
@@ -526,18 +527,18 @@ class ContentType(Enum):
 @dataclass
 class Content:
     type: ContentType
-    text: Optional[str] = None
-    cwd: Optional[str] = None
-    exit_code: Optional[float] = None
-    data: Optional[str] = None
-    mime_type: Optional[str] = None
-    description: Optional[str] = None
-    icons: Optional[List[Icon]] = None
-    name: Optional[str] = None
-    size: Optional[float] = None
-    title: Optional[str] = None
-    uri: Optional[str] = None
-    resource: Optional[Resource] = None
+    text: str | None = None
+    cwd: str | None = None
+    exit_code: float | None = None
+    data: str | None = None
+    mime_type: str | None = None
+    description: str | None = None
+    icons: list[Icon] | None = None
+    name: str | None = None
+    size: float | None = None
+    title: str | None = None
+    uri: str | None = None
+    resource: Resource | None = None
 
     @staticmethod
     def from_dict(obj: Any) -> 'Content':
@@ -590,8 +591,8 @@ def to_dict(self) -> dict:
 @dataclass
 class Result:
     content: str
-    contents: Optional[List[Content]] = None
-    detailed_content: Optional[str] = None
+    contents: list[Content] | None = None
+    detailed_content: str | None = None
 
     @staticmethod
     def from_dict(obj: Any) -> 'Result':
@@ -636,7 +637,7 @@ class ToolRequest:
     name: str
     tool_call_id: str
     arguments: Any = None
-    type: Optional[ToolRequestType] = None
+    type: ToolRequestType | None = None
 
     @staticmethod
     def from_dict(obj: Any) -> 'ToolRequest':
@@ -660,121 +661,121 @@ def to_dict(self) -> dict:
 
 @dataclass
 class Data:
-    context: Optional[Union[ContextClass, str]] = None
-    copilot_version: Optional[str] = None
-    producer: Optional[str] = None
-    selected_model: Optional[str] = None
-    session_id: Optional[str] = None
-    start_time: Optional[datetime] = None
-    version: Optional[float] = None
-    event_count: Optional[float] = None
-    resume_time: Optional[datetime] = None
-    error_type: Optional[str] = None
-    message: Optional[str] = None
-    provider_call_id: Optional[str] = None
-    stack: Optional[str] = None
-    status_code: Optional[int] = None
-    title: Optional[str] = None
-    info_type: Optional[str] = None
-    warning_type: Optional[str] = None
-    new_model: Optional[str] = None
-    previous_model: Optional[str] = None
-    new_mode: Optional[str] = None
-    previous_mode: Optional[str] = None
-    operation: Optional[Operation] = None
-    path: Optional[str] = None
+    context: ContextClass | str | None = None
+    copilot_version: str | None = None
+    producer: str | None = None
+    selected_model: str | None = None
+    session_id: str | None = None
+    start_time: datetime | None = None
+    version: float | None = None
+    event_count: float | None = None
+    resume_time: datetime | None = None
+    error_type: str | None = None
+    message: str | None = None
+    provider_call_id: str | None = None
+    stack: str | None = None
+    status_code: int | None = None
+    title: str | None = None
+    info_type: str | None = None
+    warning_type: str | None = None
+    new_model: str | None = None
+    previous_model: str | None = None
+    new_mode: str | None = None
+    previous_mode: str | None = None
+    operation: Operation | None = None
+    path: str | None = None
     """Relative path within the workspace files directory"""
 
-    handoff_time: Optional[datetime] = None
-    remote_session_id: Optional[str] = None
-    repository: Optional[Union[RepositoryClass, str]] = None
-    source_type: Optional[SourceType] = None
-    summary: Optional[str] = None
-    messages_removed_during_truncation: Optional[float] = None
-    performed_by: Optional[str] = None
-    post_truncation_messages_length: Optional[float] = None
-    post_truncation_tokens_in_messages: Optional[float] = None
-    pre_truncation_messages_length: Optional[float] = None
-    pre_truncation_tokens_in_messages: Optional[float] = None
-    token_limit: Optional[float] = None
-    tokens_removed_during_truncation: Optional[float] = None
-    events_removed: Optional[float] = None
-    up_to_event_id: Optional[str] = None
-    code_changes: Optional[CodeChanges] = None
-    current_model: Optional[str] = None
-    error_reason: Optional[str] = None
-    model_metrics: Optional[Dict[str, ModelMetric]] = None
-    session_start_time: Optional[float] = None
-    shutdown_type: Optional[ShutdownType] = None
-    total_api_duration_ms: Optional[float] = None
-    total_premium_requests: Optional[float] = None
-    branch: Optional[str] = None
-    cwd: Optional[str] = None
-    git_root: Optional[str] = None
-    current_tokens: Optional[float] = None
-    messages_length: Optional[float] = None
-    checkpoint_number: Optional[float] = None
-    checkpoint_path: Optional[str] = None
-    compaction_tokens_used: Optional[CompactionTokensUsed] = None
-    error: Optional[Union[ErrorClass, str]] = None
-    messages_removed: Optional[float] = None
-    post_compaction_tokens: Optional[float] = None
-    pre_compaction_messages_length: Optional[float] = None
-    pre_compaction_tokens: Optional[float] = None
-    request_id: Optional[str] = None
-    success: Optional[bool] = None
-    summary_content: Optional[str] = None
-    tokens_removed: Optional[float] = None
-    agent_mode: Optional[AgentMode] = None
-    attachments: Optional[List[Attachment]] = None
-    content: Optional[str] = None
-    source: Optional[str] = None
-    transformed_content: Optional[str] = None
-    turn_id: Optional[str] = None
-    intent: Optional[str] = None
-    reasoning_id: Optional[str] = None
-    delta_content: Optional[str] = None
-    total_response_size_bytes: Optional[float] = None
-    encrypted_content: Optional[str] = None
-    message_id: Optional[str] = None
-    parent_tool_call_id: Optional[str] = None
-    phase: Optional[str] = None
-    reasoning_opaque: Optional[str] = None
-    reasoning_text: Optional[str] = None
-    tool_requests: Optional[List[ToolRequest]] = None
-    api_call_id: Optional[str] = None
-    cache_read_tokens: Optional[float] = None
-    cache_write_tokens: Optional[float] = None
-    cost: Optional[float] = None
-    duration: Optional[float] = None
-    initiator: Optional[str] = None
-    input_tokens: Optional[float] = None
-    model: Optional[str] = None
-    output_tokens: Optional[float] = None
-    quota_snapshots: Optional[Dict[str, QuotaSnapshot]] = None
-    reason: Optional[str] = None
+    handoff_time: datetime | None = None
+    remote_session_id: str | None = None
+    repository: RepositoryClass | str | None = None
+    source_type: SourceType | None = None
+    summary: str | None = None
+    messages_removed_during_truncation: float | None = None
+    performed_by: str | None = None
+    post_truncation_messages_length: float | None = None
+    post_truncation_tokens_in_messages: float | None = None
+    pre_truncation_messages_length: float | None = None
+    pre_truncation_tokens_in_messages: float | None = None
+    token_limit: float | None = None
+    tokens_removed_during_truncation: float | None = None
+    events_removed: float | None = None
+    up_to_event_id: str | None = None
+    code_changes: CodeChanges | None = None
+    current_model: str | None = None
+    error_reason: str | None = None
+    model_metrics: dict[str, ModelMetric] | None = None
+    session_start_time: float | None = None
+    shutdown_type: ShutdownType | None = None
+    total_api_duration_ms: float | None = None
+    total_premium_requests: float | None = None
+    branch: str | None = None
+    cwd: str | None = None
+    git_root: str | None = None
+    current_tokens: float | None = None
+    messages_length: float | None = None
+    checkpoint_number: float | None = None
+    checkpoint_path: str | None = None
+    compaction_tokens_used: CompactionTokensUsed | None = None
+    error: ErrorClass | str | None = None
+    messages_removed: float | None = None
+    post_compaction_tokens: float | None = None
+    pre_compaction_messages_length: float | None = None
+    pre_compaction_tokens: float | None = None
+    request_id: str | None = None
+    success: bool | None = None
+    summary_content: str | None = None
+    tokens_removed: float | None = None
+    agent_mode: AgentMode | None = None
+    attachments: list[Attachment] | None = None
+    content: str | None = None
+    source: str | None = None
+    transformed_content: str | None = None
+    turn_id: str | None = None
+    intent: str | None = None
+    reasoning_id: str | None = None
+    delta_content: str | None = None
+    total_response_size_bytes: float | None = None
+    encrypted_content: str | None = None
+    message_id: str | None = None
+    parent_tool_call_id: str | None = None
+    phase: str | None = None
+    reasoning_opaque: str | None = None
+    reasoning_text: str | None = None
+    tool_requests: list[ToolRequest] | None = None
+    api_call_id: str | None = None
+    cache_read_tokens: float | None = None
+    cache_write_tokens: float | None = None
+    cost: float | None = None
+    duration: float | None = None
+    initiator: str | None = None
+    input_tokens: float | None = None
+    model: str | None = None
+    output_tokens: float | None = None
+    quota_snapshots: dict[str, QuotaSnapshot] | None = None
+    reason: str | None = None
     arguments: Any = None
-    tool_call_id: Optional[str] = None
-    tool_name: Optional[str] = None
-    mcp_server_name: Optional[str] = None
-    mcp_tool_name: Optional[str] = None
-    partial_output: Optional[str] = None
-    progress_message: Optional[str] = None
-    is_user_requested: Optional[bool] = None
-    result: Optional[Result] = None
-    tool_telemetry: Optional[Dict[str, Any]] = None
-    allowed_tools: Optional[List[str]] = None
-    name: Optional[str] = None
-    agent_description: Optional[str] = None
-    agent_display_name: Optional[str] = None
-    agent_name: Optional[str] = None
-    tools: Optional[List[str]] = None
-    hook_invocation_id: Optional[str] = None
-    hook_type: Optional[str] = None
+    tool_call_id: str | None = None
+    tool_name: str | None = None
+    mcp_server_name: str | None = None
+    mcp_tool_name: str | None = None
+    partial_output: str | None = None
+    progress_message: str | None = None
+    is_user_requested: bool | None = None
+    result: Result | None = None
+    tool_telemetry: dict[str, Any] | None = None
+    allowed_tools: list[str] | None = None
+    name: str | None = None
+    agent_description: str | None = None
+    agent_display_name: str | None = None
+    agent_name: str | None = None
+    tools: list[str] | None = None
+    hook_invocation_id: str | None = None
+    hook_type: str | None = None
     input: Any = None
     output: Any = None
-    metadata: Optional[Metadata] = None
-    role: Optional[Role] = None
+    metadata: Metadata | None = None
+    role: Role | None = None
 
     @staticmethod
     def from_dict(obj: Any) -> 'Data':
@@ -1187,8 +1188,8 @@ class SessionEvent:
     id: UUID
     timestamp: datetime
     type: SessionEventType
-    ephemeral: Optional[bool] = None
-    parent_id: Optional[UUID] = None
+    ephemeral: bool | None = None
+    parent_id: UUID | None = None
 
     @staticmethod
     def from_dict(obj: Any) -> 'SessionEvent':
diff --git a/python/copilot/jsonrpc.py b/python/copilot/jsonrpc.py
index 8b736968..fc825527 100644
--- a/python/copilot/jsonrpc.py
+++ b/python/copilot/jsonrpc.py
@@ -10,8 +10,8 @@
 import json
 import threading
 import uuid
-from collections.abc import Awaitable
-from typing import Any, Callable, Optional, Union
+from collections.abc import Awaitable, Callable
+from typing import Any
 
 
 class JsonRpcError(Exception):
@@ -30,7 +30,7 @@ class ProcessExitedError(Exception):
     pass
 
 
-RequestHandler = Callable[[dict], Union[dict, Awaitable[dict]]]
+RequestHandler = Callable[[dict], dict | Awaitable[dict]]
 
 
 class JsonRpcClient:
@@ -49,19 +49,19 @@ def __init__(self, process):
         """
         self.process = process
         self.pending_requests: dict[str, asyncio.Future] = {}
-        self.notification_handler: Optional[Callable[[str, dict], None]] = None
+        self.notification_handler: Callable[[str, dict], None] | None = None
         self.request_handlers: dict[str, RequestHandler] = {}
         self._running = False
-        self._read_thread: Optional[threading.Thread] = None
-        self._stderr_thread: Optional[threading.Thread] = None
-        self._loop: Optional[asyncio.AbstractEventLoop] = None
+        self._read_thread: threading.Thread | None = None
+        self._stderr_thread: threading.Thread | None = None
+        self._loop: asyncio.AbstractEventLoop | None = None
         self._write_lock = threading.Lock()
         self._pending_lock = threading.Lock()
-        self._process_exit_error: Optional[str] = None
+        self._process_exit_error: str | None = None
         self._stderr_output: list[str] = []
         self._stderr_lock = threading.Lock()
 
-    def start(self, loop: Optional[asyncio.AbstractEventLoop] = None):
+    def start(self, loop: asyncio.AbstractEventLoop | None = None):
         """Start listening for messages in background thread"""
         if not self._running:
             self._running = True
@@ -104,7 +104,7 @@ async def stop(self):
             self._stderr_thread.join(timeout=1.0)
 
     async def request(
-        self, method: str, params: Optional[dict] = None, timeout: Optional[float] = None
+        self, method: str, params: dict | None = None, timeout: float | None = None
     ) -> Any:
         """
         Send a JSON-RPC request and wait for response
@@ -149,7 +149,7 @@ async def request(
             with self._pending_lock:
                 self.pending_requests.pop(request_id, None)
 
-    async def notify(self, method: str, params: Optional[dict] = None):
+    async def notify(self, method: str, params: dict | None = None):
         """
         Send a JSON-RPC notification (no response expected)
 
@@ -258,7 +258,7 @@ def _read_exact(self, num_bytes: int) -> bytes:
             remaining -= len(chunk)
         return b"".join(chunks)
 
-    def _read_message(self) -> Optional[dict]:
+    def _read_message(self) -> dict | None:
         """
         Read a single JSON-RPC message with Content-Length header (blocking)
 
@@ -367,7 +367,7 @@ async def _send_response(self, request_id: str, result: dict):
         await self._send_message(response)
 
     async def _send_error_response(
-        self, request_id: str, code: int, message: str, data: Optional[dict]
+        self, request_id: str, code: int, message: str, data: dict | None
     ):
         response = {
             "jsonrpc": "2.0",
diff --git a/python/copilot/session.py b/python/copilot/session.py
index 658d2902..a02dcf1e 100644
--- a/python/copilot/session.py
+++ b/python/copilot/session.py
@@ -8,7 +8,8 @@
 import asyncio
 import inspect
 import threading
-from typing import Any, Callable, Optional, cast
+from collections.abc import Callable
+from typing import Any, cast
 
 from .generated.rpc import SessionRpc
 from .generated.session_events import SessionEvent, SessionEventType, session_event_from_dict
@@ -55,7 +56,7 @@ class CopilotSession:
         ...     unsubscribe()
     """
 
-    def __init__(self, session_id: str, client: Any, workspace_path: Optional[str] = None):
+    def __init__(self, session_id: str, client: Any, workspace_path: str | None = None):
         """
         Initialize a new CopilotSession.
 
@@ -76,13 +77,13 @@ def __init__(self, session_id: str, client: Any, workspace_path: Optional[str] =
         self._event_handlers_lock = threading.Lock()
         self._tool_handlers: dict[str, ToolHandler] = {}
         self._tool_handlers_lock = threading.Lock()
-        self._permission_handler: Optional[_PermissionHandlerFn] = None
+        self._permission_handler: _PermissionHandlerFn | None = None
         self._permission_handler_lock = threading.Lock()
-        self._user_input_handler: Optional[UserInputHandler] = None
+        self._user_input_handler: UserInputHandler | None = None
         self._user_input_handler_lock = threading.Lock()
-        self._hooks: Optional[SessionHooks] = None
+        self._hooks: SessionHooks | None = None
         self._hooks_lock = threading.Lock()
-        self._rpc: Optional[SessionRpc] = None
+        self._rpc: SessionRpc | None = None
 
     @property
     def rpc(self) -> SessionRpc:
@@ -92,7 +93,7 @@ def rpc(self) -> SessionRpc:
         return self._rpc
 
     @property
-    def workspace_path(self) -> Optional[str]:
+    def workspace_path(self) -> str | None:
         """
         Path to the session workspace directory when infinite sessions are enabled.
 
@@ -137,8 +138,8 @@ async def send(self, options: MessageOptions) -> str:
         return response["messageId"]
 
     async def send_and_wait(
-        self, options: MessageOptions, timeout: Optional[float] = None
-    ) -> Optional[SessionEvent]:
+        self, options: MessageOptions, timeout: float | None = None
+    ) -> SessionEvent | None:
         """
         Send a message to this session and wait until the session becomes idle.
 
@@ -157,7 +158,7 @@ async def send_and_wait(
             The final assistant message event, or None if none was received.
 
         Raises:
-            asyncio.TimeoutError: If the timeout is reached before session becomes idle.
+            TimeoutError: If the timeout is reached before session becomes idle.
             Exception: If the session has been destroyed or the connection fails.
 
         Example:
@@ -168,8 +169,8 @@ async def send_and_wait(
         effective_timeout = timeout if timeout is not None else 60.0
 
         idle_event = asyncio.Event()
-        error_event: Optional[Exception] = None
-        last_assistant_message: Optional[SessionEvent] = None
+        error_event: Exception | None = None
+        last_assistant_message: SessionEvent | None = None
 
         def handler(event: SessionEventTypeAlias) -> None:
             nonlocal last_assistant_message, error_event
@@ -190,10 +191,8 @@ def handler(event: SessionEventTypeAlias) -> None:
             if error_event:
                 raise error_event
             return last_assistant_message
-        except asyncio.TimeoutError:
-            raise asyncio.TimeoutError(
-                f"Timeout after {effective_timeout}s waiting for session.idle"
-            )
+        except TimeoutError:
+            raise TimeoutError(f"Timeout after {effective_timeout}s waiting for session.idle")
         finally:
             unsubscribe()
 
@@ -252,7 +251,7 @@ def _dispatch_event(self, event: SessionEvent) -> None:
             except Exception as e:
                 print(f"Error in session event handler: {e}")
 
-    def _register_tools(self, tools: Optional[list[Tool]]) -> None:
+    def _register_tools(self, tools: list[Tool] | None) -> None:
         """
         Register custom tool handlers for this session.
 
@@ -276,7 +275,7 @@ def _register_tools(self, tools: Optional[list[Tool]]) -> None:
                     continue
                 self._tool_handlers[tool.name] = tool.handler
 
-    def _get_tool_handler(self, name: str) -> Optional[ToolHandler]:
+    def _get_tool_handler(self, name: str) -> ToolHandler | None:
         """
         Retrieve a registered tool handler by name.
 
@@ -293,7 +292,7 @@ def _get_tool_handler(self, name: str) -> Optional[ToolHandler]:
         with self._tool_handlers_lock:
             return self._tool_handlers.get(name)
 
-    def _register_permission_handler(self, handler: Optional[_PermissionHandlerFn]) -> None:
+    def _register_permission_handler(self, handler: _PermissionHandlerFn | None) -> None:
         """
         Register a handler for permission requests.
 
@@ -341,7 +340,7 @@ async def _handle_permission_request(
             # Handler failed, deny permission
             return {"kind": "denied-no-approval-rule-and-could-not-request-from-user"}
 
-    def _register_user_input_handler(self, handler: Optional[UserInputHandler]) -> None:
+    def _register_user_input_handler(self, handler: UserInputHandler | None) -> None:
         """
         Register a handler for user input requests.
 
@@ -392,7 +391,7 @@ async def _handle_user_input_request(self, request: dict) -> UserInputResponse:
         except Exception:
             raise
 
-    def _register_hooks(self, hooks: Optional[SessionHooks]) -> None:
+    def _register_hooks(self, hooks: SessionHooks | None) -> None:
         """
         Register hook handlers for session lifecycle events.
 
diff --git a/python/copilot/tools.py b/python/copilot/tools.py
index 43c1ed99..e3e60099 100644
--- a/python/copilot/tools.py
+++ b/python/copilot/tools.py
@@ -9,7 +9,8 @@
 
 import inspect
 import json
-from typing import Any, Callable, TypeVar, get_type_hints, overload
+from collections.abc import Callable
+from typing import Any, TypeVar, get_type_hints, overload
 
 from pydantic import BaseModel
 
diff --git a/python/copilot/types.py b/python/copilot/types.py
index 142aee47..ef3e27aa 100644
--- a/python/copilot/types.py
+++ b/python/copilot/types.py
@@ -4,11 +4,9 @@
 
 from __future__ import annotations
 
-from collections.abc import Awaitable
+from collections.abc import Awaitable, Callable
 from dataclasses import dataclass
-from typing import Any, Callable, Literal, TypedDict, Union
-
-from typing_extensions import NotRequired
+from typing import Any, Literal, NotRequired, TypedDict
 
 # Import generated SessionEvent types
 from .generated.session_events import SessionEvent
@@ -65,7 +63,7 @@ class SelectionAttachment(TypedDict):
 
 
 # Attachment type - union of all attachment types
-Attachment = Union[FileAttachment, DirectoryAttachment, SelectionAttachment]
+Attachment = FileAttachment | DirectoryAttachment | SelectionAttachment
 
 
 # Options for creating a CopilotClient
@@ -127,7 +125,7 @@ class ToolInvocation(TypedDict):
     arguments: Any
 
 
-ToolHandler = Callable[[ToolInvocation], Union[ToolResult, Awaitable[ToolResult]]]
+ToolHandler = Callable[[ToolInvocation], ToolResult | Awaitable[ToolResult]]
 
 
 @dataclass
@@ -162,7 +160,7 @@ class SystemMessageReplaceConfig(TypedDict):
 
 
 # Union type - use one or the other
-SystemMessageConfig = Union[SystemMessageAppendConfig, SystemMessageReplaceConfig]
+SystemMessageConfig = SystemMessageAppendConfig | SystemMessageReplaceConfig
 
 
 # Permission request types
@@ -188,7 +186,7 @@ class PermissionRequestResult(TypedDict, total=False):
 
 _PermissionHandlerFn = Callable[
     [PermissionRequest, dict[str, str]],
-    Union[PermissionRequestResult, Awaitable[PermissionRequestResult]],
+    PermissionRequestResult | Awaitable[PermissionRequestResult],
 ]
 
 
@@ -220,7 +218,7 @@ class UserInputResponse(TypedDict):
 
 UserInputHandler = Callable[
     [UserInputRequest, dict[str, str]],
-    Union[UserInputResponse, Awaitable[UserInputResponse]],
+    UserInputResponse | Awaitable[UserInputResponse],
 ]
 
 
@@ -257,7 +255,7 @@ class PreToolUseHookOutput(TypedDict, total=False):
 
 PreToolUseHandler = Callable[
     [PreToolUseHookInput, dict[str, str]],
-    Union[PreToolUseHookOutput, None, Awaitable[Union[PreToolUseHookOutput, None]]],
+    PreToolUseHookOutput | None | Awaitable[PreToolUseHookOutput | None],
 ]
 
 
@@ -281,7 +279,7 @@ class PostToolUseHookOutput(TypedDict, total=False):
 
 PostToolUseHandler = Callable[
     [PostToolUseHookInput, dict[str, str]],
-    Union[PostToolUseHookOutput, None, Awaitable[Union[PostToolUseHookOutput, None]]],
+    PostToolUseHookOutput | None | Awaitable[PostToolUseHookOutput | None],
 ]
 
 
@@ -303,11 +301,7 @@ class UserPromptSubmittedHookOutput(TypedDict, total=False):
 
 UserPromptSubmittedHandler = Callable[
     [UserPromptSubmittedHookInput, dict[str, str]],
-    Union[
-        UserPromptSubmittedHookOutput,
-        None,
-        Awaitable[Union[UserPromptSubmittedHookOutput, None]],
-    ],
+    UserPromptSubmittedHookOutput | None | Awaitable[UserPromptSubmittedHookOutput | None],
 ]
 
 
@@ -329,7 +323,7 @@ class SessionStartHookOutput(TypedDict, total=False):
 
 SessionStartHandler = Callable[
     [SessionStartHookInput, dict[str, str]],
-    Union[SessionStartHookOutput, None, Awaitable[Union[SessionStartHookOutput, None]]],
+    SessionStartHookOutput | None | Awaitable[SessionStartHookOutput | None],
 ]
 
 
@@ -353,7 +347,7 @@ class SessionEndHookOutput(TypedDict, total=False):
 
 SessionEndHandler = Callable[
     [SessionEndHookInput, dict[str, str]],
-    Union[SessionEndHookOutput, None, Awaitable[Union[SessionEndHookOutput, None]]],
+    SessionEndHookOutput | None | Awaitable[SessionEndHookOutput | None],
 ]
 
 
@@ -378,7 +372,7 @@ class ErrorOccurredHookOutput(TypedDict, total=False):
 
 ErrorOccurredHandler = Callable[
     [ErrorOccurredHookInput, dict[str, str]],
-    Union[ErrorOccurredHookOutput, None, Awaitable[Union[ErrorOccurredHookOutput, None]]],
+    ErrorOccurredHookOutput | None | Awaitable[ErrorOccurredHookOutput | None],
 ]
 
 
@@ -420,7 +414,7 @@ class MCPRemoteServerConfig(TypedDict, total=False):
     headers: NotRequired[dict[str, str]]  # HTTP headers
 
 
-MCPServerConfig = Union[MCPLocalServerConfig, MCPRemoteServerConfig]
+MCPServerConfig = MCPLocalServerConfig | MCPRemoteServerConfig
 
 
 # ============================================================================
diff --git a/python/e2e/test_session.py b/python/e2e/test_session.py
index 4842d782..47cb1b5a 100644
--- a/python/e2e/test_session.py
+++ b/python/e2e/test_session.py
@@ -444,7 +444,7 @@ def on_event(event):
         # Wait for completion
         try:
             await asyncio.wait_for(done_event.wait(), timeout=60)
-        except asyncio.TimeoutError:
+        except TimeoutError:
             pytest.fail("Timed out waiting for session.idle")
 
         # Should have received delta events
@@ -498,7 +498,7 @@ def on_event(event):
         # Wait for session to become idle
         try:
             await asyncio.wait_for(idle_event.wait(), timeout=60)
-        except asyncio.TimeoutError:
+        except TimeoutError:
             pytest.fail("Timed out waiting for session.idle")
 
         # Should have received multiple events
diff --git a/python/e2e/testharness/context.py b/python/e2e/testharness/context.py
index 4417f567..9eb4c6a6 100644
--- a/python/e2e/testharness/context.py
+++ b/python/e2e/testharness/context.py
@@ -9,7 +9,6 @@
 import shutil
 import tempfile
 from pathlib import Path
-from typing import Optional
 
 from copilot import CopilotClient
 
@@ -46,8 +45,8 @@ def __init__(self):
         self.home_dir: str = ""
         self.work_dir: str = ""
         self.proxy_url: str = ""
-        self._proxy: Optional[CapiProxy] = None
-        self._client: Optional[CopilotClient] = None
+        self._proxy: CapiProxy | None = None
+        self._client: CopilotClient | None = None
 
     async def setup(self):
         """Set up the test context with a shared client."""
diff --git a/python/e2e/testharness/proxy.py b/python/e2e/testharness/proxy.py
index e26ec65c..65dd8bda 100644
--- a/python/e2e/testharness/proxy.py
+++ b/python/e2e/testharness/proxy.py
@@ -9,7 +9,7 @@
 import platform
 import re
 import subprocess
-from typing import Any, Optional
+from typing import Any
 
 import httpx
 
@@ -18,8 +18,8 @@ class CapiProxy:
     """Manages a replaying proxy server for E2E tests."""
 
     def __init__(self):
-        self._process: Optional[subprocess.Popen] = None
-        self._proxy_url: Optional[str] = None
+        self._process: subprocess.Popen | None = None
+        self._proxy_url: str | None = None
 
     async def start(self) -> str:
         """Launch the proxy server and return its URL."""
@@ -107,6 +107,6 @@ async def get_exchanges(self) -> list[dict[str, Any]]:
             return resp.json()
 
     @property
-    def url(self) -> Optional[str]:
+    def url(self) -> str | None:
         """Return the proxy URL, or None if not started."""
         return self._proxy_url
diff --git a/python/pyproject.toml b/python/pyproject.toml
index 6c4d3e72..170534ba 100644
--- a/python/pyproject.toml
+++ b/python/pyproject.toml
@@ -7,7 +7,7 @@ name = "github-copilot-sdk"
 version = "0.1.0"
 description = "Python SDK for GitHub Copilot CLI"
 readme = "README.md"
-requires-python = ">=3.9"
+requires-python = ">=3.11"
 license = "MIT"
 # license-files is set by scripts/build-wheels.mjs for bundled CLI wheels
 authors = [
@@ -17,15 +17,14 @@ classifiers = [
     "Development Status :: 3 - Alpha",
     "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",
+    "Programming Language :: Python :: 3.13",
+    "Programming Language :: Python :: 3.14",
 ]
 dependencies = [
     "python-dateutil>=2.9.0.post0",
     "pydantic>=2.0",
-    "typing-extensions>=4.0.0",
 ]
 
 [project.urls]
@@ -47,7 +46,7 @@ packages = ["copilot"]
 
 [tool.ruff]
 line-length = 100
-target-version = "py39"
+target-version = "py311"
 exclude = [
     "generated",
     "copilot/generated",
@@ -61,9 +60,6 @@ select = [
     "I",  # isort
     "UP", # pyupgrade
 ]
-ignore = [
-    "UP006",
-]
 
 [tool.ruff.format]
 quote-style = "double"
diff --git a/python/test_client.py b/python/test_client.py
index c6ad027f..f31c3e9e 100644
--- a/python/test_client.py
+++ b/python/test_client.py
@@ -213,6 +213,9 @@ async def test_resume_session_forwards_client_name(self):
 
             async def mock_request(method, params):
                 captured[method] = params
+                if method == "session.resume":
+                    # Return a fake response to avoid needing real auth
+                    return {"sessionId": session.session_id}
                 return await original_request(method, params)
 
             client._client.request = mock_request
diff --git a/scripts/codegen/python.ts b/scripts/codegen/python.ts
index aa688782..944ac269 100644
--- a/scripts/codegen/python.ts
+++ b/scripts/codegen/python.ts
@@ -21,6 +21,54 @@ import {
 
 // ── Utilities ───────────────────────────────────────────────────────────────
 
+/**
+ * Modernize quicktype's Python 3.7 output to Python 3.11+ syntax:
+ * - Optional[T] → T | None
+ * - List[T] → list[T]
+ * - Dict[K, V] → dict[K, V]
+ * - Type[T] → type[T]
+ * - Callable from collections.abc instead of typing
+ * - Clean up unused typing imports
+ */
+function modernizePython(code: string): string {
+    // Replace Optional[X] with X | None (handles nested brackets)
+    code = code.replace(/Optional\[([^\[\]]*(?:\[[^\[\]]*\])*[^\[\]]*)\]/g, "$1 | None");
+
+    // Replace Union[X, Y] with X | Y
+    code = code.replace(/Union\[([^\[\]]*(?:\[[^\[\]]*\])*[^\[\]]*)\]/g, (_match, inner: string) => {
+        return inner.split(",").map((s: string) => s.trim()).join(" | ");
+    });
+
+    // Replace List[X] with list[X]
+    code = code.replace(/\bList\[/g, "list[");
+
+    // Replace Dict[K, V] with dict[K, V]
+    code = code.replace(/\bDict\[/g, "dict[");
+
+    // Replace Type[T] with type[T]
+    code = code.replace(/\bType\[/g, "type[");
+
+    // Move Callable from typing to collections.abc
+    code = code.replace(
+        /from typing import (.*), Callable$/m,
+        "from typing import $1\nfrom collections.abc import Callable"
+    );
+    code = code.replace(
+        /from typing import Callable, (.*)$/m,
+        "from typing import $1\nfrom collections.abc import Callable"
+    );
+
+    // Remove now-unused imports from typing (Optional, List, Dict, Type)
+    code = code.replace(/from typing import (.+)$/m, (_match, imports: string) => {
+        const items = imports.split(",").map((s: string) => s.trim());
+        const remove = new Set(["Optional", "List", "Dict", "Type", "Union"]);
+        const kept = items.filter((i: string) => !remove.has(i));
+        return `from typing import ${kept.join(", ")}`;
+    });
+
+    return code;
+}
+
 function toSnakeCase(s: string): string {
     return s
         .replace(/([a-z])([A-Z])/g, "$1_$2")
@@ -75,6 +123,8 @@ async function generateSessionEvents(schemaPath?: string): Promise<void> {
     code = code.replace(/: Any$/gm, ": Any = None");
     // Fix bare except: to use Exception (required by ruff/pylint)
     code = code.replace(/except:/g, "except Exception:");
+    // Modernize to Python 3.11+ syntax
+    code = modernizePython(code);
 
     // Add UNKNOWN enum value for forward compatibility
     code = code.replace(
@@ -162,6 +212,8 @@ async function generateRpc(schemaPath?: string): Promise<void> {
     typesCode = typesCode.replace(/except:/g, "except Exception:");
     // Remove unnecessary pass when class has methods (quicktype generates pass for empty schemas)
     typesCode = typesCode.replace(/^(\s*)pass\n\n(\s*@staticmethod)/gm, "$2");
+    // Modernize to Python 3.11+ syntax
+    typesCode = modernizePython(typesCode);
 
     const lines: string[] = [];
     lines.push(`"""