fix: Move AgentInput to types submodule (#746)

Author: Unshure

src/strands/agent/agent.py

@@ -22,7 +22,6 @@
     Mapping,
     Optional,
     Type,
-    TypeAlias,
     TypeVar,
     Union,
     cast,
@@ -51,6 +50,7 @@
 from ..tools.executors._executor import ToolExecutor
 from ..tools.registry import ToolRegistry
 from ..tools.watcher import ToolWatcher
+from ..types.agent import AgentInput
 from ..types.content import ContentBlock, Message, Messages
 from ..types.exceptions import ContextWindowOverflowException
 from ..types.tools import ToolResult, ToolUse
@@ -67,8 +67,6 @@
 # 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:

src/strands/types/agent.py

@@ -0,0 +1,10 @@
+"""Agent-related type definitions for the SDK.
+
+This module defines the types used for an Agent.
+"""
+
+from typing import TypeAlias
+
+from .content import ContentBlock, Messages
+
+AgentInput: TypeAlias = str | list[ContentBlock] | Messages | None