Consistently use Dataclasses in Python SDK (github#216)

* Initial plan

* Add TypedDict types for ping() and stop() return values

Co-authored-by: friggeri <106686+friggeri@users.noreply.github.com>

* Convert all TypedDict response types to dataclasses

Co-authored-by: friggeri <106686+friggeri@users.noreply.github.com>

* Add proper validation to from_dict methods

Co-authored-by: friggeri <106686+friggeri@users.noreply.github.com>

* Fix ty type checker errors after dataclass conversion

Co-authored-by: friggeri <106686+friggeri@users.noreply.github.com>

* fix type error and flaky pyton test

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: friggeri <106686+friggeri@users.noreply.github.com>
Co-authored-by: Adrien Friggeri <adrien@friggeri.net>

Author: Copilot

python/copilot/__init__.py

@@ -24,11 +24,13 @@
     PermissionHandler,
     PermissionRequest,
     PermissionRequestResult,
+    PingResponse,
     ProviderConfig,
     ResumeSessionConfig,
     SessionConfig,
     SessionEvent,
     SessionMetadata,
+    StopError,
     Tool,
     ToolHandler,
     ToolInvocation,
@@ -56,11 +58,13 @@
     "PermissionHandler",
     "PermissionRequest",
     "PermissionRequestResult",
+    "PingResponse",
     "ProviderConfig",
     "ResumeSessionConfig",
     "SessionConfig",
     "SessionEvent",
     "SessionMetadata",
+    "StopError",
     "Tool",
     "ToolHandler",
     "ToolInvocation",

python/copilot/client.py

@@ -19,7 +19,7 @@
 import subprocess
 import threading
 from dataclasses import asdict, is_dataclass
-from typing import Any, Optional, cast
+from typing import Any, Optional
 
 from .generated.session_events import session_event_from_dict
 from .jsonrpc import JsonRpcClient
@@ -32,10 +32,12 @@
     GetAuthStatusResponse,
     GetStatusResponse,
     ModelInfo,
+    PingResponse,
     ProviderConfig,
     ResumeSessionConfig,
     SessionConfig,
     SessionMetadata,
+    StopError,
     ToolHandler,
     ToolInvocation,
     ToolResult,
@@ -220,7 +222,7 @@ async def start(self) -> None:
             self._state = "error"
             raise
 
-    async def stop(self) -> list[dict[str, str]]:
+    async def stop(self) -> list["StopError"]:
         """
         Stop the CLI server and close all active sessions.
 
@@ -230,16 +232,16 @@ async def stop(self) -> list[dict[str, str]]:
         3. Terminates the CLI server process (if spawned by this client)
 
         Returns:
-            A list of errors that occurred during cleanup, each as a dict with
-            a 'message' key. An empty list indicates all cleanup succeeded.
+            A list of StopError objects containing error messages that occurred
+            during cleanup. An empty list indicates all cleanup succeeded.
 
         Example:
             >>> errors = await client.stop()
             >>> if errors:
             ...     for error in errors:
-            ...         print(f"Cleanup error: {error['message']}")
+            ...         print(f"Cleanup error: {error.message}")
         """
-        errors: list[dict[str, str]] = []
+        errors: list[StopError] = []
 
         # Atomically take ownership of all sessions and clear the dict
         # so no other thread can access them
@@ -251,7 +253,9 @@ async def stop(self) -> list[dict[str, str]]:
             try:
                 await session.destroy()
             except Exception as e:
-                errors.append({"message": f"Failed to destroy session {session.session_id}: {e}"})
+                errors.append(
+                    StopError(message=f"Failed to destroy session {session.session_id}: {e}")
+                )
 
         # Close client
         if self._client:
@@ -570,67 +574,69 @@ def get_state(self) -> ConnectionState:
         """
         return self._state
 
-    async def ping(self, message: Optional[str] = None) -> dict:
+    async def ping(self, message: Optional[str] = None) -> "PingResponse":
         """
         Send a ping request to the server to verify connectivity.
 
         Args:
             message: Optional message to include in the ping.
 
         Returns:
-            A dict containing the ping response with 'message', 'timestamp',
-            and 'protocolVersion' keys.
+            A PingResponse object containing the ping response.
 
         Raises:
             RuntimeError: If the client is not connected.
 
         Example:
             >>> response = await client.ping("health check")
-            >>> print(f"Server responded at {response['timestamp']}")
+            >>> print(f"Server responded at {response.timestamp}")
         """
         if not self._client:
             raise RuntimeError("Client not connected")
 
-        return await self._client.request("ping", {"message": message})
+        result = await self._client.request("ping", {"message": message})
+        return PingResponse.from_dict(result)
 
     async def get_status(self) -> "GetStatusResponse":
         """
         Get CLI status including version and protocol information.
 
         Returns:
-            A GetStatusResponse containing version and protocolVersion.
+            A GetStatusResponse object containing version and protocolVersion.
 
         Raises:
             RuntimeError: If the client is not connected.
 
         Example:
             >>> status = await client.get_status()
-            >>> print(f"CLI version: {status['version']}")
+            >>> print(f"CLI version: {status.version}")
         """
         if not self._client:
             raise RuntimeError("Client not connected")
 
-        return await self._client.request("status.get", {})
+        result = await self._client.request("status.get", {})
+        return GetStatusResponse.from_dict(result)
 
     async def get_auth_status(self) -> "GetAuthStatusResponse":
         """
         Get current authentication status.
 
         Returns:
-            A GetAuthStatusResponse containing authentication state.
+            A GetAuthStatusResponse object containing authentication state.
 
         Raises:
             RuntimeError: If the client is not connected.
 
         Example:
             >>> auth = await client.get_auth_status()
-            >>> if auth['isAuthenticated']:
-            ...     print(f"Logged in as {auth.get('login')}")
+            >>> if auth.isAuthenticated:
+            ...     print(f"Logged in as {auth.login}")
         """
         if not self._client:
             raise RuntimeError("Client not connected")
 
-        return await self._client.request("auth.getStatus", {})
+        result = await self._client.request("auth.getStatus", {})
+        return GetAuthStatusResponse.from_dict(result)
 
     async def list_models(self) -> list["ModelInfo"]:
         """
@@ -646,13 +652,14 @@ async def list_models(self) -> list["ModelInfo"]:
         Example:
             >>> models = await client.list_models()
             >>> for model in models:
-            ...     print(f"{model['id']}: {model['name']}")
+            ...     print(f"{model.id}: {model.name}")
         """
         if not self._client:
             raise RuntimeError("Client not connected")
 
         response = await self._client.request("models.list", {})
-        return response.get("models", [])
+        models_data = response.get("models", [])
+        return [ModelInfo.from_dict(model) for model in models_data]
 
     async def list_sessions(self) -> list["SessionMetadata"]:
         """
@@ -661,23 +668,22 @@ async def list_sessions(self) -> list["SessionMetadata"]:
         Returns metadata about each session including ID, timestamps, and summary.
 
         Returns:
-            A list of session metadata dictionaries with keys: sessionId (str),
-            startTime (str), modifiedTime (str), summary (str, optional),
-            and isRemote (bool).
+            A list of SessionMetadata objects.
 
         Raises:
             RuntimeError: If the client is not connected.
 
         Example:
             >>> sessions = await client.list_sessions()
             >>> for session in sessions:
-            ...     print(f"Session: {session['sessionId']}")
+            ...     print(f"Session: {session.sessionId}")
         """
         if not self._client:
             raise RuntimeError("Client not connected")
 
         response = await self._client.request("session.list", {})
-        return response.get("sessions", [])
+        sessions_data = response.get("sessions", [])
+        return [SessionMetadata.from_dict(session) for session in sessions_data]
 
     async def delete_session(self, session_id: str) -> None:
         """
@@ -714,7 +720,7 @@ async def _verify_protocol_version(self) -> None:
         """Verify that the server's protocol version matches the SDK's expected version."""
         expected_version = get_sdk_protocol_version()
         ping_result = await self.ping()
-        server_version = ping_result.get("protocolVersion")
+        server_version = ping_result.protocolVersion
 
         if server_version is None:
             raise RuntimeError(
@@ -845,11 +851,11 @@ async def read_port():
             if not process or not process.stdout:
                 raise RuntimeError("Process not started or stdout not available")
             while True:
-                line = cast(bytes, await loop.run_in_executor(None, process.stdout.readline))
+                line = await loop.run_in_executor(None, process.stdout.readline)
                 if not line:
                     raise RuntimeError("CLI process exited before announcing port")
 
-                line_str = line.decode()
+                line_str = line.decode() if isinstance(line, bytes) else line
                 match = re.search(r"listening on port (\d+)", line_str, re.IGNORECASE)
                 if match:
                     self._actual_port = int(match.group(1))

python/copilot/tools.py

@@ -186,7 +186,7 @@ def _normalize_result(result: Any) -> ToolResult:
 
     # ToolResult passes through directly
     if isinstance(result, dict) and "resultType" in result and "textResultForLlm" in result:
-        return result  # type: ignore
+        return result
 
     # Strings pass through directly
     if isinstance(result, str):