feat: Add Citations and Attributions to Agent Node (#18558)

Co-authored-by: oneness0 <2902216407@qq.com>
Co-authored-by: Novice <novice12185727@gmail.com>

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

@@ -22,7 +22,7 @@ from core.workflow.enums import SystemVariableKey
 from core.workflow.graph_engine.entities.event import AgentLogEvent
 from core.workflow.nodes.base import BaseNode
 from core.workflow.nodes.enums import NodeType
-from core.workflow.nodes.event import RunCompletedEvent, RunStreamChunkEvent
+from core.workflow.nodes.event import RunCompletedEvent, RunRetrieverResourceEvent, RunStreamChunkEvent
 from core.workflow.utils.variable_template_parser import VariableTemplateParser
 from extensions.ext_database import db
 from factories import file_factory
@@ -373,6 +373,12 @@ class ToolNode(BaseNode[ToolNodeData]):
                     agent_logs.append(agent_log)
 
                 yield agent_log
+            elif message.type == ToolInvokeMessage.MessageType.RETRIEVER_RESOURCES:
+                assert isinstance(message.message, ToolInvokeMessage.RetrieverResourceMessage)
+                yield RunRetrieverResourceEvent(
+                    retriever_resources=message.message.retriever_resources,
+                    context=message.message.context,
+                )
 
         # Add agent_logs to outputs['json'] to ensure frontend can access thinking process
         json_output: list[dict[str, Any]] = []