Add examples to showcase patterns (#55)

* add chess example

* wip

* wip

* fix tool schema generation

* fixes

* Agent handle exception

Co-authored-by: Jack Gerrits <jackgerrits@users.noreply.github.com>

* format

* mypy

* fix test for annotated

---------

Co-authored-by: Jack Gerrits <jackgerrits@users.noreply.github.com>

examples/chess_game.py

@@ -0,0 +1,119 @@
+"""This is an example of simulating a chess game with two agents
+that play against each other, using tools to reason about the game state
+and make moves."""
+
+import argparse
+import asyncio
+import logging
+from typing import Annotated
+
+from agnext.application import SingleThreadedAgentRuntime
+from agnext.chat.agents.chat_completion_agent import ChatCompletionAgent
+from agnext.chat.patterns.group_chat import GroupChat, GroupChatOutput
+from agnext.chat.types import TextMessage
+from agnext.components.models import OpenAI, SystemMessage
+from agnext.components.tools import FunctionTool
+from agnext.core import AgentRuntime
+from chess import SQUARE_NAMES, Board, Move
+from chess import piece_name as get_piece_name
+
+logging.basicConfig(level=logging.WARNING)
+logging.getLogger("agnext").setLevel(logging.DEBUG)
+
+
+class ChessGameOutput(GroupChatOutput):  # type: ignore
+    def on_message_received(self, message: TextMessage) -> None:  # type: ignore
+        pass
+
+    def get_output(self) -> None:
+        pass
+
+    def reset(self) -> None:
+        pass
+
+
+def chess_game(runtime: AgentRuntime) -> GroupChat:  # type: ignore
+    """Create agents for a chess game and return the group chat."""
+
+    # Create the board.
+    board = Board()
+
+    # Create shared tools.
+    def get_legal_moves() -> Annotated[str, "A list of legal moves in UCI format."]:
+        return "Possible moves are: " + ", ".join([str(move) for move in board.legal_moves])
+
+    get_legal_moves_tool = FunctionTool(get_legal_moves, description="Get legal moves.")
+
+    def make_move(input: Annotated[str, "A move in UCI format."]) -> Annotated[str, "Result of the move."]:
+        move = Move.from_uci(input)
+        board.push(move)
+        print(board.unicode(borders=True))
+        # Get the piece name.
+        piece = board.piece_at(move.to_square)
+        assert piece is not None
+        piece_symbol = piece.unicode_symbol()
+        piece_name = get_piece_name(piece.piece_type)
+        if piece_symbol.isupper():
+            piece_name = piece_name.capitalize()
+        return f"Moved {piece_name} ({piece_symbol}) from {SQUARE_NAMES[move.from_square]} to {SQUARE_NAMES[move.to_square]}."
+
+    make_move_tool = FunctionTool(make_move, description="Call this tool to make a move.")
+
+    tools = [get_legal_moves_tool, make_move_tool]
+
+    black = ChatCompletionAgent(
+        name="PlayerBlack",
+        description="Player playing black.",
+        runtime=runtime,
+        system_messages=[
+            SystemMessage(
+                content="You are a chess player and you play as black. "
+                "First call get_legal_moves() first, to get list of legal moves. "
+                "Then call make_move(move) to make a move."
+            ),
+        ],
+        model_client=OpenAI(model="gpt-4-turbo"),
+        tools=tools,
+    )
+    white = ChatCompletionAgent(
+        name="PlayerWhite",
+        description="Player playing white.",
+        runtime=runtime,
+        system_messages=[
+            SystemMessage(
+                content="You are a chess player and you play as white. "
+                "First call get_legal_moves() first, to get list of legal moves. "
+                "Then call make_move(move) to make a move."
+            ),
+        ],
+        model_client=OpenAI(model="gpt-4-turbo"),
+        tools=tools,
+    )
+    game_chat = GroupChat(
+        name="ChessGame",
+        description="A chess game between two agents.",
+        runtime=runtime,
+        agents=[white, black],
+        num_rounds=10,
+        output=ChessGameOutput(),
+    )
+    return game_chat
+
+
+async def main(message: str) -> None:
+    runtime = SingleThreadedAgentRuntime()
+    game_chat = chess_game(runtime)
+    future = runtime.send_message(TextMessage(content=message, source="Human"), game_chat)
+    while not future.done():
+        await runtime.process_next()
+
+
+if __name__ == "__main__":
+    parser = argparse.ArgumentParser(description="Run a chess game between two agents.")
+    parser.add_argument(
+        "--initial-message",
+        default="Please make a move.",
+        help="The initial message to send to the agent playing white.",
+    )
+    args = parser.parse_args()
+    asyncio.run(main(args.initial_message))

pyproject.toml

@@ -31,6 +31,9 @@ dev = [
     "pytest-xdist",
     "types-Pillow",
     "polars",
+    # Dependencies for the examples.
+    "chess",
+    "tavily-python",
 ]
 docs = ["sphinx", "furo", "sphinxcontrib-apidoc", "myst-parser"]
 

src/agnext/application/_single_threaded_agent_runtime.py

@@ -10,6 +10,7 @@ from ..core.exceptions import MessageDroppedException
 from ..core.intervention import DropMessage, InterventionHandler
 
 logger = logging.getLogger("agnext")
+event_logger = logging.getLogger("agnext.events")
 
 
 @dataclass(kw_only=True)
@@ -67,7 +68,9 @@ class SingleThreadedAgentRuntime(AgentRuntime):
         return list(self._agents)
 
     @property
-    def unprocessed_messages(self) -> Sequence[PublishMessageEnvelope | SendMessageEnvelope | ResponseMessageEnvelope]:
+    def unprocessed_messages(
+        self,
+    ) -> Sequence[PublishMessageEnvelope | SendMessageEnvelope | ResponseMessageEnvelope]:
         return self._message_queue
 
     # Returns the response of the message
@@ -82,6 +85,18 @@ class SingleThreadedAgentRuntime(AgentRuntime):
         if cancellation_token is None:
             cancellation_token = CancellationToken()
 
+        logger.info(f"Sending message of type {type(message).__name__} to {recipient.name}: {message.__dict__}")
+
+        # event_logger.info(
+        #     MessageEvent(
+        #         payload=message,
+        #         sender=sender,
+        #         receiver=recipient,
+        #         kind=MessageKind.DIRECT,
+        #         delivery_stage=DeliveryStage.SEND,
+        #     )
+        # )
+
         future = asyncio.get_event_loop().create_future()
         if recipient not in self._agents:
             future.set_exception(Exception("Recipient not found"))
@@ -108,6 +123,18 @@ class SingleThreadedAgentRuntime(AgentRuntime):
         if cancellation_token is None:
             cancellation_token = CancellationToken()
 
+        logger.info(f"Publishing message of type {type(message).__name__} to all subscribers: {message.__dict__}")
+
+        # event_logger.info(
+        #     MessageEvent(
+        #         payload=message,
+        #         sender=sender,
+        #         receiver=None,
+        #         kind=MessageKind.PUBLISH,
+        #         delivery_stage=DeliveryStage.SEND,
+        #     )
+        # )
+
         self._message_queue.append(
             PublishMessageEnvelope(
                 message=message,
@@ -137,8 +164,17 @@ class SingleThreadedAgentRuntime(AgentRuntime):
         try:
             sender_name = message_envelope.sender.name if message_envelope.sender is not None else "Unknown"
             logger.info(
-                f"Calling message handler for {recipient.name} with message type {type(message_envelope.message).__name__} from {sender_name}"
+                f"Calling message handler for {recipient.name} with message type {type(message_envelope.message).__name__} sent by {sender_name}"
             )
+            # event_logger.info(
+            #     MessageEvent(
+            #         payload=message_envelope.message,
+            #         sender=message_envelope.sender,
+            #         receiver=recipient,
+            #         kind=MessageKind.DIRECT,
+            #         delivery_stage=DeliveryStage.DELIVER,
+            #     )
+            # )
             response = await recipient.on_message(
                 message_envelope.message,
                 cancellation_token=message_envelope.cancellation_token,
@@ -162,9 +198,19 @@ class SingleThreadedAgentRuntime(AgentRuntime):
             if message_envelope.sender is not None and agent.name == message_envelope.sender.name:
                 continue
 
+            sender_name = message_envelope.sender.name if message_envelope.sender is not None else "Unknown"
             logger.info(
-                f"Calling message handler for {agent.name} with message type {type(message_envelope.message).__name__} published by {message_envelope.sender.name if message_envelope.sender is not None else 'Unknown'}"
+                f"Calling message handler for {agent.name} with message type {type(message_envelope.message).__name__} published by {sender_name}"
             )
+            # event_logger.info(
+            #     MessageEvent(
+            #         payload=message_envelope.message,
+            #         sender=message_envelope.sender,
+            #         receiver=agent,
+            #         kind=MessageKind.PUBLISH,
+            #         delivery_stage=DeliveryStage.DELIVER,
+            #     )
+            # )
 
             future = agent.on_message(
                 message_envelope.message,
@@ -182,9 +228,23 @@ class SingleThreadedAgentRuntime(AgentRuntime):
 
     async def _process_response(self, message_envelope: ResponseMessageEnvelope) -> None:
         recipient_name = message_envelope.recipient.name if message_envelope.recipient is not None else "Unknown"
-        logger.info(
-            f"Resolving response for recipient {recipient_name} from {message_envelope.sender.name} with message type {type(message_envelope.message).__name__}"
+        content = (
+            message_envelope.message.__dict__
+            if hasattr(message_envelope.message, "__dict__")
+            else message_envelope.message
         )
+        logger.info(
+            f"Resolving response with message type {type(message_envelope.message).__name__} for recipient {recipient_name} from {message_envelope.sender.name}: {content}"
+        )
+        # event_logger.info(
+        #     MessageEvent(
+        #         payload=message_envelope.message,
+        #         sender=message_envelope.sender,
+        #         receiver=message_envelope.recipient,
+        #         kind=MessageKind.RESPOND,
+        #         delivery_stage=DeliveryStage.DELIVER,
+        #     )
+        # )
         message_envelope.future.set_result(message_envelope.message)
 
     async def process_next(self) -> None:

src/agnext/application/logging/__init__.py

@@ -1,6 +1,13 @@
-from ._events import LLMCallEvent
+from ._events import DeliveryStage, LLMCallEvent, MessageEvent, MessageKind
 from ._llm_usage import LLMUsageTracker
 
 EVENT_LOGGER_NAME = "agnext.events"
 
-__all__ = ["LLMCallEvent", "EVENT_LOGGER_NAME", "LLMUsageTracker"]
+__all__ = [
+    "LLMCallEvent",
+    "EVENT_LOGGER_NAME",
+    "LLMUsageTracker",
+    "MessageEvent",
+    "MessageKind",
+    "DeliveryStage",
+]

src/agnext/application/logging/_events.py

@@ -1,6 +1,9 @@
 import json
+from enum import Enum
 from typing import Any, cast
 
+from ...core import Agent
+
 
 class LLMCallEvent:
     def __init__(self, *, prompt_tokens: int, completion_tokens: int, **kwargs: Any) -> None:
@@ -23,6 +26,50 @@ class LLMCallEvent:
         self.kwargs = kwargs
         self.kwargs["prompt_tokens"] = prompt_tokens
         self.kwargs["completion_tokens"] = completion_tokens
+        self.kwargs["type"] = "LLMCall"
+
+    @property
+    def prompt_tokens(self) -> int:
+        return cast(int, self.kwargs["prompt_tokens"])
+
+    @property
+    def completion_tokens(self) -> int:
+        return cast(int, self.kwargs["completion_tokens"])
+
+    # This must output the event in a json serializable format
+    def __str__(self) -> str:
+        return json.dumps(self.kwargs)
+
+
+class MessageKind(Enum):
+    DIRECT = 1
+    PUBLISH = 2
+    RESPOND = 3
+
+
+class DeliveryStage(Enum):
+    SEND = 1
+    DELIVER = 2
+
+
+class MessageEvent:
+    def __init__(
+        self,
+        *,
+        payload: Any,
+        sender: Agent | None,
+        receiver: Agent | None,
+        kind: MessageKind,
+        delivery_stage: DeliveryStage,
+        **kwargs: Any,
+    ) -> None:
+        self.kwargs = kwargs
+        self.kwargs["payload"] = payload
+        self.kwargs["sender"] = None if sender is None else sender.name
+        self.kwargs["receiver"] = None if receiver is None else receiver.name
+        self.kwargs["kind"] = kind
+        self.kwargs["delivery_stage"] = delivery_stage
+        self.kwargs["type"] = "Message"
 
     @property
     def prompt_tokens(self) -> int:

src/agnext/chat/agents/chat_completion_agent.py

@@ -128,7 +128,10 @@ class ChatCompletionAgent(BaseChatAgent, TypeRoutedAgent):
                 continue
             # Execute the function.
             future = self.execute_function(
-                function_call.name, arguments, function_call.id, cancellation_token=cancellation_token
+                function_call.name,
+                arguments,
+                function_call.id,
+                cancellation_token=cancellation_token,
             )
             # Append the async result.
             execution_futures.append(future)
@@ -149,24 +152,22 @@ class ChatCompletionAgent(BaseChatAgent, TypeRoutedAgent):
         return tool_call_result_msg
 
     async def execute_function(
-        self, name: str, args: Dict[str, Any], call_id: str, cancellation_token: CancellationToken
+        self,
+        name: str,
+        args: Dict[str, Any],
+        call_id: str,
+        cancellation_token: CancellationToken,
     ) -> Tuple[str, str]:
         # Find tool
         tool = next((t for t in self._tools if t.name == name), None)
         if tool is None:
-            raise ValueError(f"Tool {name} not found.")
+            return (f"Error: tool {name} not found.", call_id)
         try:
             result = await tool.run_json(args, cancellation_token)
-            result_json_or_str = result.model_dump()
-            if isinstance(result, dict):
-                result_str = json.dumps(result_json_or_str)
-            elif isinstance(result_json_or_str, str):
-                result_str = result_json_or_str
-            else:
-                raise ValueError(f"Unexpected result type: {type(result)}")
+            result_as_str = tool.return_value_as_string(result)
         except Exception as e:
-            result_str = f"Error: {str(e)}"
-        return (result_str, call_id)
+            result_as_str = f"Error: {str(e)}"
+        return (result_as_str, call_id)
 
     def save_state(self) -> Mapping[str, Any]:
         return {

src/agnext/chat/utils.py

@@ -73,17 +73,17 @@ def convert_messages_to_llm_messages(
     for message in messages:
         match message:
             case (
-                TextMessage(_, source=source)
-                | MultiModalMessage(_, source=source)
-                | FunctionCallMessage(_, source=source)
+                TextMessage(content=_, source=source)
+                | MultiModalMessage(content=_, source=source)
+                | FunctionCallMessage(content=_, source=source)
             ) if source == self_name:
                 converted_message_1 = convert_content_message_to_assistant_message(message, handle_unrepresentable)
                 if converted_message_1 is not None:
                     result.append(converted_message_1)
             case (
-                TextMessage(_, source=source)
-                | MultiModalMessage(_, source=source)
-                | FunctionCallMessage(_, source=source)
+                TextMessage(content=_, source=source)
+                | MultiModalMessage(content=_, source=source)
+                | FunctionCallMessage(content=_, source=source)
             ) if source != self_name:
                 converted_message_2 = convert_content_message_to_user_message(message, handle_unrepresentable)
                 if converted_message_2 is not None:

src/agnext/components/_type_routed_agent.py

@@ -105,18 +105,18 @@ def message_handler(
 
         @wraps(func)
         async def wrapper(self: Any, message: ReceivesT, cancellation_token: CancellationToken) -> ProducesT:
-            if strict:
-                if type(message) not in target_types:
+            if type(message) not in target_types:
+                if strict:
                     raise CantHandleException(f"Message type {type(message)} not in target types {target_types}")
                 else:
                     logger.warning(f"Message type {type(message)} not in target types {target_types}")
 
             return_value = await func(self, message, cancellation_token)
 
-            if strict:
-                if return_value is not AnyType and type(return_value) not in return_types:
+            if AnyType not in return_types and type(return_value) not in return_types:
+                if strict:
                     raise ValueError(f"Return type {type(return_value)} not in return types {return_types}")
-                elif return_value is not AnyType:
+                else:
                     logger.warning(f"Return type {type(return_value)} not in return types {return_types}")
 
             return return_value
@@ -134,7 +134,10 @@ def message_handler(
 class TypeRoutedAgent(BaseAgent):
     def __init__(self, name: str, router: AgentRuntime) -> None:
         # Self is already bound to the handlers
-        self._handlers: Dict[Type[Any], Callable[[Any, CancellationToken], Coroutine[Any, Any, Any | None]]] = {}
+        self._handlers: Dict[
+            Type[Any],
+            Callable[[Any, CancellationToken], Coroutine[Any, Any, Any | None]],
+        ] = {}
 
         for attr in dir(self):
             if callable(getattr(self, attr, None)):

src/agnext/components/models/_openai_client.py

@@ -1,5 +1,6 @@
 import inspect
 import logging
+import re
 import warnings
 from typing import (
     Any,
@@ -11,6 +12,7 @@ from typing import (
     Sequence,
     Set,
     Union,
+    cast,
 )
 
 from openai import AsyncAzureOpenAI, AsyncOpenAI
@@ -27,6 +29,7 @@ from openai.types.chat import (
     ChatCompletionUserMessageParam,
     completion_create_params,
 )
+from openai.types.shared_params import FunctionDefinition, FunctionParameters
 from typing_extensions import Unpack
 
 from ...application.logging import EVENT_LOGGER_NAME, LLMCallEvent
@@ -205,15 +208,47 @@ def convert_tools(
 ) -> List[ChatCompletionToolParam]:
     result: List[ChatCompletionToolParam] = []
     for tool in tools:
+        tool_schema = tool.schema
         result.append(
-            {
-                "type": "function",
-                "function": tool.schema,  # type: ignore
-            }
+            ChatCompletionToolParam(
+                type="function",
+                function=FunctionDefinition(
+                    name=tool_schema["name"],
+                    description=tool_schema["description"] if "description" in tool_schema else "",
+                    parameters=cast(FunctionParameters, tool_schema["parameters"])
+                    if "parameters" in tool_schema
+                    else {},
+                ),
+            )
         )
+    # Check if all tools have valid names.
+    for tool_param in result:
+        assert_valid_name(tool_param["function"]["name"])
     return result
 
 
+def normalize_name(name: str) -> str:
+    """
+    LLMs sometimes ask functions while ignoring their own format requirements, this function should be used to replace invalid characters with "_".
+
+    Prefer _assert_valid_name for validating user configuration or input
+    """
+    return re.sub(r"[^a-zA-Z0-9_-]", "_", name)[:64]
+
+
+def assert_valid_name(name: str) -> str:
+    """
+    Ensure that configured names are valid, raises ValueError if not.
+
+    For munging LLM responses use _normalize_name to ensure LLM specified names don't break the API.
+    """
+    if not re.match(r"^[a-zA-Z0-9_-]+$", name):
+        raise ValueError(f"Invalid name: {name}. Only letters, numbers, '_' and '-' are allowed.")
+    if len(name) > 64:
+        raise ValueError(f"Invalid name: {name}. Name must be less than 64 characters.")
+    return name
+
+
 class BaseOpenAI(ChatCompletionClient):
     def __init__(
         self,
@@ -293,7 +328,10 @@ class BaseOpenAI(ChatCompletionClient):
         if len(tools) > 0:
             converted_tools = convert_tools(tools)
             result = await self._client.chat.completions.create(
-                messages=oai_messages, stream=False, tools=converted_tools, **create_args
+                messages=oai_messages,
+                stream=False,
+                tools=converted_tools,
+                **create_args,
             )
         else:
             result = await self._client.chat.completions.create(messages=oai_messages, stream=False, **create_args)
@@ -331,7 +369,11 @@ class BaseOpenAI(ChatCompletionClient):
 
             # NOTE: If OAI response type changes, this will need to be updated
             content = [
-                FunctionCall(id=x.id, arguments=x.function.arguments, name=x.function.name)
+                FunctionCall(
+                    id=x.id,
+                    arguments=x.function.arguments,
+                    name=normalize_name(x.function.name),
+                )
                 for x in choice.message.tool_calls
             ]
             finish_reason = "function_calls"

src/agnext/components/tools/_base.py

@@ -1,14 +1,29 @@
 import json
 from abc import ABC, abstractmethod
-from typing import Any, Dict, Generic, Mapping, Protocol, Type, TypeVar
+from collections.abc import Sequence
+from typing import Any, Dict, Generic, Mapping, Protocol, Type, TypedDict, TypeVar
 
 from pydantic import BaseModel
+from typing_extensions import NotRequired
 
 from ...core import CancellationToken
+from .._function_utils import normalize_annotated_type
 
 T = TypeVar("T", bound=BaseModel, contravariant=True)
 
 
+class ParametersSchema(TypedDict):
+    type: str
+    properties: Dict[str, Any]
+    required: NotRequired[Sequence[str]]
+
+
+class ToolSchema(TypedDict):
+    parameters: NotRequired[ParametersSchema]
+    name: str
+    description: NotRequired[str]
+
+
 class Tool(Protocol):
     @property
     def name(self) -> str: ...
@@ -17,7 +32,7 @@ class Tool(Protocol):
     def description(self) -> str: ...
 
     @property
-    def schema(self) -> Mapping[str, Any]: ...
+    def schema(self) -> ToolSchema: ...
 
     def args_type(self) -> Type[BaseModel]: ...
 
@@ -40,20 +55,36 @@ StateT = TypeVar("StateT", bound=BaseModel)
 
 
 class BaseTool(ABC, Tool, Generic[ArgsT, ReturnT]):
-    def __init__(self, args_type: Type[ArgsT], return_type: Type[ReturnT], name: str, description: str) -> None:
+    def __init__(
+        self,
+        args_type: Type[ArgsT],
+        return_type: Type[ReturnT],
+        name: str,
+        description: str,
+    ) -> None:
         self._args_type = args_type
-        self._return_type = return_type
+        # Normalize Annotated to the base type.
+        self._return_type = normalize_annotated_type(return_type)
         self._name = name
         self._description = description
 
     @property
-    def schema(self) -> Mapping[str, Any]:
+    def schema(self) -> ToolSchema:
         model_schema = self._args_type.model_json_schema()
-        parameter_schema: Dict[str, Any] = dict()
-        parameter_schema["parameters"] = model_schema["properties"]
-        parameter_schema["name"] = self._name
-        parameter_schema["description"] = self._description
-        return parameter_schema
+
+        tool_schema = ToolSchema(
+            name=self._name,
+            description=self._description,
+            parameters=ParametersSchema(
+                type="object",
+                properties=model_schema["properties"],
+            ),
+        )
+        if "required" in model_schema:
+            assert "parameters" in tool_schema
+            tool_schema["parameters"]["required"] = model_schema["required"]
+
+        return tool_schema
 
     @property
     def name(self) -> str:
@@ -97,7 +128,12 @@ class BaseTool(ABC, Tool, Generic[ArgsT, ReturnT]):
 
 class BaseToolWithState(BaseTool[ArgsT, ReturnT], ABC, Generic[ArgsT, ReturnT, StateT]):
     def __init__(
-        self, args_type: Type[ArgsT], return_type: Type[ReturnT], state_type: Type[StateT], name: str, description: str
+        self,
+        args_type: Type[ArgsT],
+        return_type: Type[ReturnT],
+        state_type: Type[StateT],
+        name: str,
+        description: str,
     ) -> None:
         super().__init__(args_type, return_type, name, description)
         self._state_type = state_type

src/agnext/components/tools/_function_tool.py

@@ -32,7 +32,12 @@ class FunctionTool(BaseTool[BaseModel, BaseModel]):
         else:
             if self._has_cancellation_support:
                 result = await asyncio.get_event_loop().run_in_executor(
-                    None, functools.partial(self._func, **args.model_dump(), cancellation_token=cancellation_token)
+                    None,
+                    functools.partial(
+                        self._func,
+                        **args.model_dump(),
+                        cancellation_token=cancellation_token,
+                    ),
                 )
             else:
                 future = asyncio.get_event_loop().run_in_executor(

tests/test_tools.py

@@ -36,9 +36,54 @@ def test_tool_schema_generation() -> None:
     schema = MyTool().schema
 
     assert schema["name"] == "TestTool"
+    assert "description" in schema
     assert schema["description"] == "Description of test tool."
-    assert schema["parameters"]["query"]["description"] == "The description."
-    assert len(schema["parameters"]) == 1
+    assert "parameters" in schema
+    assert schema["parameters"]["type"] == "object"
+    assert "properties" in schema["parameters"]
+    assert schema["parameters"]["properties"]["query"]["description"] == "The description."
+    assert schema["parameters"]["properties"]["query"]["type"] == "string"
+    assert "required" in schema["parameters"]
+    assert schema["parameters"]["required"] == ["query"]
+    assert len(schema["parameters"]["properties"]) == 1
+
+def test_func_tool_schema_generation() -> None:
+    def my_function(arg: str, other: Annotated[int, "int arg"], nonrequired: int = 5) -> MyResult:
+        return MyResult(result="test")
+    tool = FunctionTool(my_function, description="Function tool.")
+    schema = tool.schema
+
+    assert schema["name"] == "my_function"
+    assert "description" in schema
+    assert schema["description"] == "Function tool."
+    assert "parameters" in schema
+    assert schema["parameters"]["type"] == "object"
+    assert schema["parameters"]["properties"].keys() == {"arg", "other", "nonrequired"}
+    assert schema["parameters"]["properties"]["arg"]["type"] == "string"
+    assert schema["parameters"]["properties"]["arg"]["description"] == "arg"
+    assert schema["parameters"]["properties"]["other"]["type"] == "integer"
+    assert schema["parameters"]["properties"]["other"]["description"] == "int arg"
+    assert schema["parameters"]["properties"]["nonrequired"]["type"] == "integer"
+    assert schema["parameters"]["properties"]["nonrequired"]["description"] == "nonrequired"
+    assert "required" in schema["parameters"]
+    assert schema["parameters"]["required"] == ["arg", "other"]
+    assert len(schema["parameters"]["properties"]) == 3
+
+def test_func_tool_schema_generation_only_default_arg() -> None:
+    def my_function(arg: str = "default") -> MyResult:
+        return MyResult(result="test")
+    tool = FunctionTool(my_function, description="Function tool.")
+    schema = tool.schema
+
+    assert schema["name"] == "my_function"
+    assert "description" in schema
+    assert schema["description"] == "Function tool."
+    assert "parameters" in schema
+    assert len(schema["parameters"]["properties"]) == 1
+    assert schema["parameters"]["properties"]["arg"]["type"] == "string"
+    assert schema["parameters"]["properties"]["arg"]["description"] == "arg"
+    assert "required" not in schema["parameters"]
+
 
 @pytest.mark.asyncio
 async def test_tool_run()-> None:
@@ -128,7 +173,7 @@ def test_func_tool_return_annotated()-> None:
     assert tool.name == "my_function"
     assert tool.description == "Function tool."
     assert issubclass(tool.args_type(), BaseModel)
-    assert tool.return_type() == Annotated[str, "test description"]
+    assert tool.return_type() == str
     assert tool.state_type() is None
 
 def test_func_tool_no_args()-> None: