feat(client): support agent_name injection to enable isolated memory and custom prompts (#1253)

* feat(client): 添加agent_name参数支持自定义代理名称

允许在初始化DeerFlowClient时指定代理名称，该名称将用于中间件构建和系统提示模板

* test: add coverage for agent_name parameter in DeerFlowClient

* fix(client): address PR review comments for agent_name injection

---------

Co-authored-by: Willem Jiang <willem.jiang@gmail.com>

backend/tests/test_client.py

@@ -56,6 +56,7 @@ class TestClientInit:
         assert client._thinking_enabled is True
         assert client._subagent_enabled is False
         assert client._plan_mode is False
+        assert client._agent_name is None
         assert client._checkpointer is None
         assert client._agent is None
 
@@ -66,11 +67,20 @@ class TestClientInit:
                 thinking_enabled=False,
                 subagent_enabled=True,
                 plan_mode=True,
+                agent_name="test-agent"
             )
         assert c._model_name == "gpt-4"
         assert c._thinking_enabled is False
         assert c._subagent_enabled is True
         assert c._plan_mode is True
+        assert c._agent_name == "test-agent"
+
+    def test_invalid_agent_name(self, mock_app_config):
+        with patch("deerflow.client.get_app_config", return_value=mock_app_config):
+            with pytest.raises(ValueError, match="Invalid agent name"):
+                DeerFlowClient(agent_name="invalid name with spaces!")
+            with pytest.raises(ValueError, match="Invalid agent name"):
+                DeerFlowClient(agent_name="../path/traversal")
 
     def test_custom_config_path(self, mock_app_config):
         with (
@@ -188,6 +198,23 @@ class TestStream:
         msg_events = _ai_events(events)
         assert msg_events[0].data["content"] == "Hello!"
 
+    def test_context_propagation(self, client):
+        """stream() passes agent_name to the context."""
+        agent = _make_agent_mock([{"messages": [AIMessage(content="ok", id="ai-1")]}])
+
+        client._agent_name = "test-agent-1"
+        with (
+            patch.object(client, "_ensure_agent"),
+            patch.object(client, "_agent", agent),
+        ):
+            list(client.stream("hi", thread_id="t1"))
+        
+        # Verify context passed to agent.stream
+        agent.stream.assert_called_once()
+        call_kwargs = agent.stream.call_args.kwargs
+        assert call_kwargs["context"]["thread_id"] == "t1"
+        assert call_kwargs["context"]["agent_name"] == "test-agent-1"
+
     def test_tool_call_and_result(self, client):
         """stream() emits messages-tuple events for tool calls and results."""
         ai = AIMessage(content="", id="ai-1", tool_calls=[{"name": "bash", "args": {"cmd": "ls"}, "id": "tc-1"}])
@@ -359,13 +386,19 @@ class TestEnsureAgent:
         with (
             patch("deerflow.client.create_chat_model"),
             patch("deerflow.client.create_agent", return_value=mock_agent),
-            patch("deerflow.client._build_middlewares", return_value=[]),
-            patch("deerflow.client.apply_prompt_template", return_value="prompt"),
+            patch("deerflow.client._build_middlewares", return_value=[]) as mock_build_middlewares,
+            patch("deerflow.client.apply_prompt_template", return_value="prompt") as mock_apply_prompt,
             patch.object(client, "_get_tools", return_value=[]),
         ):
+            client._agent_name = "custom-agent"
             client._ensure_agent(config)
 
         assert client._agent is mock_agent
+        # Verify agent_name propagation
+        mock_build_middlewares.assert_called_once()
+        assert mock_build_middlewares.call_args.kwargs.get("agent_name") == "custom-agent"
+        mock_apply_prompt.assert_called_once()
+        assert mock_apply_prompt.call_args.kwargs.get("agent_name") == "custom-agent"
 
     def test_uses_default_checkpointer_when_available(self, client):
         mock_agent = MagicMock()