ECO-184: use enums instead of literals

api/core/tools/entities/tool_entities.py

@@ -123,6 +123,16 @@ class ApiProviderAuthType(StrEnum):
         raise ValueError(f"invalid mode value '{value}', expected one of: {valid}")
 
 
+class ToolAuthType(StrEnum):
+    """
+    Enum class for tool authentication type.
+    Determines whether OAuth credentials are workspace-level or end-user-level.
+    """
+
+    WORKSPACE = "workspace"
+    END_USER = "end_user"
+
+
 class ToolInvokeMessage(BaseModel):
     class TextMessage(BaseModel):
         text: str

api/core/workflow/nodes/tool/entities.py

@@ -3,7 +3,7 @@ from typing import Any, Literal, Union
 from pydantic import BaseModel, field_validator
 from pydantic_core.core_schema import ValidationInfo
 
-from core.tools.entities.tool_entities import ToolProviderType
+from core.tools.entities.tool_entities import ToolAuthType, ToolProviderType
 from core.workflow.nodes.base.entities import BaseNodeData
 
 
@@ -16,7 +16,7 @@ class ToolEntity(BaseModel):
     tool_configurations: dict[str, Any]
     credential_id: str | None = None
     plugin_unique_identifier: str | None = None  # redundancy
-    auth_type: Literal["workspace", "end_user"] = "workspace"  # OAuth authentication level
+    auth_type: ToolAuthType = ToolAuthType.WORKSPACE  # OAuth authentication level
 
     @field_validator("tool_configurations", mode="before")
     @classmethod