fix: Add AgentInput TypeAlias (strands-agents#738)

Author: Unshure

CONTRIBUTING.md

@@ -49,7 +49,7 @@ This project uses [hatchling](https://hatch.pypa.io/latest/build/#hatchling) as
 
    Alternatively, install development dependencies in a manually created virtual environment:
    ```bash
-   pip install -e ".[dev]" && pip install -e ".[litellm]"
+   pip install -e ".[all]"
    ```
 
 

src/strands/agent/agent.py

@@ -14,7 +14,19 @@
 import logging
 import random
 from concurrent.futures import ThreadPoolExecutor
-from typing import Any, AsyncGenerator, AsyncIterator, Callable, Mapping, Optional, Type, TypeVar, Union, cast
+from typing import (
+    Any,
+    AsyncGenerator,
+    AsyncIterator,
+    Callable,
+    Mapping,
+    Optional,
+    Type,
+    TypeAlias,
+    TypeVar,
+    Union,
+    cast,
+)
 
 from opentelemetry import trace as trace_api
 from pydantic import BaseModel
@@ -55,6 +67,8 @@
 # TypeVar for generic structured output
 T = TypeVar("T", bound=BaseModel)
 
+AgentInput: TypeAlias = str | list[ContentBlock] | Messages | None
+
 
 # Sentinel class and object to distinguish between explicit None and default parameter value
 class _DefaultCallbackHandlerSentinel:
@@ -361,7 +375,7 @@ def tool_names(self) -> list[str]:
         all_tools = self.tool_registry.get_all_tools_config()
         return list(all_tools.keys())
 
-    def __call__(self, prompt: str | list[ContentBlock] | Messages | None = None, **kwargs: Any) -> AgentResult:
+    def __call__(self, prompt: AgentInput = None, **kwargs: Any) -> AgentResult:
         """Process a natural language prompt through the agent's event loop.
 
         This method implements the conversational interface with multiple input patterns:
@@ -394,9 +408,7 @@ def execute() -> AgentResult:
             future = executor.submit(execute)
             return future.result()
 
-    async def invoke_async(
-        self, prompt: str | list[ContentBlock] | Messages | None = None, **kwargs: Any
-    ) -> AgentResult:
+    async def invoke_async(self, prompt: AgentInput = None, **kwargs: Any) -> AgentResult:
         """Process a natural language prompt through the agent's event loop.
 
         This method implements the conversational interface with multiple input patterns:
@@ -427,7 +439,7 @@ async def invoke_async(
 
         return cast(AgentResult, event["result"])
 
-    def structured_output(self, output_model: Type[T], prompt: str | list[ContentBlock] | Messages | None = None) -> T:
+    def structured_output(self, output_model: Type[T], prompt: AgentInput = None) -> T:
         """This method allows you to get structured output from the agent.
 
         If you pass in a prompt, it will be used temporarily without adding it to the conversation history.
@@ -456,9 +468,7 @@ def execute() -> T:
             future = executor.submit(execute)
             return future.result()
 
-    async def structured_output_async(
-        self, output_model: Type[T], prompt: str | list[ContentBlock] | Messages | None = None
-    ) -> T:
+    async def structured_output_async(self, output_model: Type[T], prompt: AgentInput = None) -> T:
         """This method allows you to get structured output from the agent.
 
         If you pass in a prompt, it will be used temporarily without adding it to the conversation history.
@@ -517,7 +527,7 @@ async def structured_output_async(
 
     async def stream_async(
         self,
-        prompt: str | list[ContentBlock] | Messages | None = None,
+        prompt: AgentInput = None,
         **kwargs: Any,
     ) -> AsyncIterator[Any]:
         """Process a natural language prompt and yield events as an async iterator.
@@ -657,7 +667,7 @@ async def _execute_event_loop_cycle(self, invocation_state: dict[str, Any]) -> A
             async for event in events:
                 yield event
 
-    def _convert_prompt_to_messages(self, prompt: str | list[ContentBlock] | Messages | None) -> Messages:
+    def _convert_prompt_to_messages(self, prompt: AgentInput) -> Messages:
         messages: Messages | None = None
         if prompt is not None:
             if isinstance(prompt, str):

src/strands/session/file_session_manager.py

@@ -92,7 +92,7 @@ def _get_message_path(self, session_id: str, agent_id: str, message_id: int) ->
         """
         if not isinstance(message_id, int):
             raise ValueError(f"message_id=<{message_id}> | message id must be an integer")
-        
+
         agent_path = self._get_agent_path(session_id, agent_id)
         return os.path.join(agent_path, "messages", f"{MESSAGE_PREFIX}{message_id}.json")
 

src/strands/session/s3_session_manager.py

@@ -116,13 +116,13 @@ def _get_message_path(self, session_id: str, agent_id: str, message_id: int) ->
 
         Returns:
             The key for the message
-            
+
         Raises:
             ValueError: If message_id is not an integer.
         """
         if not isinstance(message_id, int):
             raise ValueError(f"message_id=<{message_id}> | message id must be an integer")
-            
+
         agent_path = self._get_agent_path(session_id, agent_id)
         return f"{agent_path}messages/{MESSAGE_PREFIX}{message_id}.json"
 

tests/strands/agent/test_agent.py

@@ -1830,6 +1830,7 @@ def test_agent_with_list_of_message_and_content_block():
     with pytest.raises(ValueError, match="Input prompt must be of type: `str | list[Contentblock] | Messages | None`."):
         agent([{"role": "user", "content": [{"text": "hello"}]}, {"text", "hello"}])
 
+
 def test_agent_tool_call_parameter_filtering_integration(mock_randint):
     """Test that tool calls properly filter parameters in message recording."""
     mock_randint.return_value = 42
@@ -1861,4 +1862,3 @@ def test_tool(action: str) -> str:
     assert '"action": "test_value"' in tool_call_text
     assert '"agent"' not in tool_call_text
     assert '"extra_param"' not in tool_call_text
-

tests/strands/session/test_file_session_manager.py

@@ -396,7 +396,7 @@ def test__get_agent_path_invalid_agent_id(agent_id, file_manager):
     "message_id",
     [
         "../../../secret",
-        "../../attack", 
+        "../../attack",
         "../escape",
         "path/traversal",
         "not_an_int",

tests/strands/session/test_s3_session_manager.py

@@ -362,7 +362,7 @@ def test__get_agent_path_invalid_agent_id(agent_id, s3_manager):
     "message_id",
     [
         "../../../secret",
-        "../../attack", 
+        "../../attack",
         "../escape",
         "path/traversal",
         "not_an_int",