diff --git a/src/claude_agent_sdk/__init__.py b/src/claude_agent_sdk/__init__.py
index d66541f5..ad2ff81a 100644
--- a/src/claude_agent_sdk/__init__.py
+++ b/src/claude_agent_sdk/__init__.py
@@ -65,6 +65,7 @@
     ContextUsageCategory,
     ContextUsageResponse,
     DeferredToolUse,
+    EffortLevel,
     HookCallback,
     HookContext,
     HookEventMessage,
@@ -601,6 +602,7 @@ async def call_tool(name: str, arguments: dict[str, Any]) -> Any:
     # Agent support
     "AgentDefinition",
     "SettingSource",
+    "EffortLevel",
     # Plugin support
     "SdkPluginConfig",
     # Session listing
diff --git a/src/claude_agent_sdk/types.py b/src/claude_agent_sdk/types.py
index 12cdc214..a6eb5c2f 100644
--- a/src/claude_agent_sdk/types.py
+++ b/src/claude_agent_sdk/types.py
@@ -4,7 +4,7 @@
 from collections.abc import Awaitable, Callable
 from dataclasses import dataclass, field
 from pathlib import Path
-from typing import TYPE_CHECKING, Any, Literal, Protocol
+from typing import TYPE_CHECKING, Any, Literal, Protocol, TypeAlias
 
 if sys.version_info >= (3, 11):
     from typing import NotRequired, Required, TypedDict
@@ -31,6 +31,9 @@
 # Agent definitions
 SettingSource = Literal["user", "project", "local"]
 
+# Thinking effort levels
+EffortLevel: TypeAlias = Literal["low", "medium", "high", "xhigh", "max"]
+
 
 class SystemPromptPreset(TypedDict):
     """System prompt preset configuration."""
@@ -96,7 +99,7 @@ class AgentDefinition:
     initialPrompt: str | None = None  # noqa: N815
     maxTurns: int | None = None  # noqa: N815
     background: bool | None = None
-    effort: Literal["low", "medium", "high", "xhigh", "max"] | int | None = None
+    effort: EffortLevel | int | None = None
     permissionMode: PermissionMode | None = None  # noqa: N815
 
 
@@ -1864,7 +1867,7 @@ class ClaudeAgentOptions:
     See https://docs.anthropic.com/en/docs/build-with-claude/adaptive-thinking.
     """
 
-    effort: Literal["low", "medium", "high", "xhigh", "max"] | None = None
+    effort: EffortLevel | None = None
     """Controls how much effort Claude puts into its response.
 
     Works with adaptive thinking to guide thinking depth.