Export EffortLevel type alias (#951)

## Summary
- add a public `EffortLevel` type alias for Claude effort string levels
- reuse the alias in `AgentDefinition` and `ClaudeAgentOptions`
- export the alias from the package root for downstream SDK wrappers

Closes #938

## Testing
- `.venv/bin/python -m pytest tests/test_types.py -q`
- `.venv/bin/python -m ruff check src/claude_agent_sdk/types.py
src/claude_agent_sdk/__init__.py tests/test_types.py`
- `.venv/bin/python -m ruff format --check src/claude_agent_sdk/types.py
src/claude_agent_sdk/__init__.py tests/test_types.py`
- `git diff --check`

Author: Jaksenc

src/claude_agent_sdk/__init__.py

@@ -65,6 +65,7 @@
     ContextUsageCategory,
     ContextUsageResponse,
     DeferredToolUse,
+    EffortLevel,
     HookCallback,
     HookContext,
     HookEventMessage,
@@ -528,6 +529,7 @@ async def call_tool(name: str, arguments: dict[str, Any]) -> Any:
     "ClaudeSDKClient",
     # Types
     "PermissionMode",
+    "EffortLevel",
     "McpServerConfig",
     "McpSdkServerConfig",
     "McpServerStatus",

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
@@ -30,6 +30,7 @@
 
 # Agent definitions
 SettingSource = Literal["user", "project", "local"]
+EffortLevel: TypeAlias = Literal["low", "medium", "high", "xhigh", "max"]
 
 
 class SystemPromptPreset(TypedDict):
@@ -96,7 +97,7 @@ 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 +1865,7 @@ 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.

tests/test_types.py

@@ -1,8 +1,11 @@
 """Tests for Claude SDK type definitions."""
 
+from typing import get_args
+
 from claude_agent_sdk import (
     AssistantMessage,
     ClaudeAgentOptions,
+    EffortLevel,
     NotificationHookInput,
     NotificationHookSpecificOutput,
     PermissionRequestHookInput,
@@ -24,6 +27,11 @@
 )
 
 
+def test_effort_level_is_exported():
+    """EffortLevel is part of the public package API for downstream wrappers."""
+    assert set(get_args(EffortLevel)) == {"low", "medium", "high", "xhigh", "max"}
+
+
 class TestPermissionUpdate:
     """Test PermissionUpdate wire-format conversion."""