Move imports to module level and expand test coverage

- Move StructuredTool and build_result_envelope imports to top of chat_agent.py
- Add tests for ChatAgent._build_workflow emitter parameter
- Add test for MCP provider description templating with {original} placeholder
- Apply ruff format to modified files

Author: abrookins

redis_sre_agent/agent/chat_agent.py

@@ -12,6 +12,7 @@
 from typing import Any, Awaitable, Callable, Dict, List, Optional, TypedDict
 
 from langchain_core.messages import AIMessage, BaseMessage, HumanMessage, SystemMessage, ToolMessage
+from langchain_core.tools import StructuredTool
 from langchain_openai import ChatOpenAI
 from langgraph.checkpoint.memory import MemorySaver
 from langgraph.graph import END, StateGraph
@@ -28,6 +29,8 @@
 from redis_sre_agent.tools.manager import ToolManager
 from redis_sre_agent.tools.models import ToolCapability
 
+from .helpers import build_result_envelope
+
 logger = logging.getLogger(__name__)
 tracer = trace.get_tracer(__name__)
 
@@ -220,10 +223,6 @@ def _build_workflow(
             adapters: List of tool adapters for the ToolNode
             emitter: Optional progress emitter for status updates
         """
-        from langchain_core.tools import StructuredTool
-
-        from .helpers import build_result_envelope
-
         tooldefs_by_name = {t.name: t for t in tool_mgr.get_tools()}
 
         # We'll dynamically add expand_evidence tool when envelopes are available

tests/unit/agent/test_chat_agent.py

@@ -212,3 +212,55 @@ def test_state_has_required_fields(self):
         assert "iteration_count" in state
         assert "max_iterations" in state
         assert "signals_envelopes" in state
+
+
+class TestChatAgentWorkflowBuild:
+    """Test the _build_workflow method and emitter parameter."""
+
+    @patch("redis_sre_agent.agent.chat_agent.ChatOpenAI")
+    def test_build_workflow_accepts_emitter(self, mock_chat_openai):
+        """Test that _build_workflow accepts an emitter parameter."""
+        mock_llm = MagicMock()
+        mock_chat_openai.return_value = mock_llm
+
+        agent = ChatAgent()
+
+        # Create a mock tool manager
+        mock_tool_mgr = MagicMock()
+        mock_tool_mgr.get_tools.return_value = []
+        mock_tool_mgr.get_status_update.return_value = None
+
+        # Create a mock emitter
+        emitter = NullEmitter()
+
+        # Should not raise - emitter is now accepted
+        workflow = agent._build_workflow(
+            tool_mgr=mock_tool_mgr,
+            llm_with_tools=mock_llm,
+            adapters=[],
+            emitter=emitter,
+        )
+
+        assert workflow is not None
+
+    @patch("redis_sre_agent.agent.chat_agent.ChatOpenAI")
+    def test_build_workflow_works_without_emitter(self, mock_chat_openai):
+        """Test that _build_workflow works when emitter is None."""
+        mock_llm = MagicMock()
+        mock_chat_openai.return_value = mock_llm
+
+        agent = ChatAgent()
+
+        # Create a mock tool manager
+        mock_tool_mgr = MagicMock()
+        mock_tool_mgr.get_tools.return_value = []
+
+        # Should not raise when emitter is None
+        workflow = agent._build_workflow(
+            tool_mgr=mock_tool_mgr,
+            llm_with_tools=mock_llm,
+            adapters=[],
+            emitter=None,
+        )
+
+        assert workflow is not None

tests/unit/tools/mcp_provider/test_mcp_provider.py

@@ -96,6 +96,29 @@ def test_get_description_with_override(self):
         assert provider._get_description("no_override", "MCP desc") == "MCP desc"
         assert provider._get_description("unknown", "MCP desc") == "MCP desc"
 
+    def test_get_description_with_original_template(self):
+        """Test that {original} placeholder is replaced with MCP description."""
+        config = MCPServerConfig(
+            command="test",
+            tools={
+                "templated_tool": MCPToolConfig(description="Custom context. {original}"),
+                "prepended": MCPToolConfig(
+                    description="WARNING: Use carefully. {original} See docs for details."
+                ),
+            },
+        )
+        provider = MCPToolProvider(server_name="test", server_config=config)
+
+        # Template should replace {original} with the MCP description
+        assert (
+            provider._get_description("templated_tool", "Original MCP description")
+            == "Custom context. Original MCP description"
+        )
+        assert (
+            provider._get_description("prepended", "Search for files.")
+            == "WARNING: Use carefully. Search for files. See docs for details."
+        )
+
     def test_get_tool_config(self):
         """Test getting tool config."""
         tool_config = MCPToolConfig(