Render snippet fallback in search XML when description is absent

Display truncated content preview from the new snippet field when
no AI description is available, giving agents useful context for
all search results.

Author: IvanBiruk

src/tests/test_response_transformer.py

@@ -305,6 +305,94 @@ def test_preserves_server_order(self):
         assert important_line < less_important_line
         assert less_important_line < another_line
 
+    def test_snippet_fallback_when_no_description(self):
+        """Test that snippet is rendered as truncated content when description is absent."""
+        response = {
+            "results": [
+                {
+                    "kind": "Symbol",
+                    "identifier": "owner/repo::file.py::func",
+                    "location": {
+                        "path": "file.py",
+                        "range": {"start": {"line": 1}, "end": {"line": 5}}
+                    },
+                    "snippet": "def func(): return 42"
+                }
+            ]
+        }
+
+        result = transform_search_response_to_xml(response)
+
+        assert '<content truncated="true">' in result
+        assert "def func(): return 42" in result
+        assert "</content>" in result
+        assert "<description>" not in result
+
+    def test_snippet_html_escaped(self):
+        """Test that snippet content is HTML-escaped."""
+        response = {
+            "results": [
+                {
+                    "kind": "Symbol",
+                    "identifier": "owner/repo::file.py::func",
+                    "location": {
+                        "path": "file.py",
+                        "range": {"start": {"line": 1}, "end": {"line": 5}}
+                    },
+                    "snippet": 'if x < 10 && y > 5: return "<ok>"'
+                }
+            ]
+        }
+
+        result = transform_search_response_to_xml(response)
+
+        assert "&lt;" in result
+        assert "&amp;" in result
+        assert '<content truncated="true">' in result
+
+    def test_description_takes_precedence_over_snippet(self):
+        """Test that description wins when both description and snippet are present."""
+        response = {
+            "results": [
+                {
+                    "kind": "Symbol",
+                    "identifier": "owner/repo::file.py::func",
+                    "location": {
+                        "path": "file.py",
+                        "range": {"start": {"line": 1}, "end": {"line": 5}}
+                    },
+                    "description": "A helper function",
+                    "snippet": "def func(): return 42"
+                }
+            ]
+        }
+
+        result = transform_search_response_to_xml(response)
+
+        assert "<description>A helper function</description>" in result
+        assert '<content truncated="true">' not in result
+
+    def test_no_description_no_snippet_self_closing(self):
+        """Test that results without description and without snippet use self-closing tags."""
+        response = {
+            "results": [
+                {
+                    "kind": "Symbol",
+                    "identifier": "owner/repo::file.py::func",
+                    "location": {
+                        "path": "file.py",
+                        "range": {"start": {"line": 1}, "end": {"line": 5}}
+                    }
+                }
+            ]
+        }
+
+        result = transform_search_response_to_xml(response)
+
+        assert "/>" in result
+        assert "<description>" not in result
+        assert "<content" not in result
+
     def test_data_preservation_without_content(self):
         """Test that all essential data is preserved."""
         response = {

src/utils/response_transformer.py

@@ -99,6 +99,10 @@ def _build_result_info(result: Dict) -> Dict:
     if result.get("description"):
         result_info["description"] = result["description"]
 
+    # Add snippet if present (fallback content when description is missing)
+    if result.get("snippet"):
+        result_info["snippet"] = result["snippet"]
+
     # Add contentByteSize if present
     if result.get("contentByteSize") is not None:
         result_info["contentByteSize"] = result["contentByteSize"]
@@ -118,10 +122,15 @@ def _build_xml_without_content(file_groups: OrderedDict) -> str:
         for result in results:
             attrs = _build_xml_attributes(path, result)
             description = result.get("description")
+            snippet = result.get("snippet")
             if description:
                 xml_parts.append(f'  <search_result {" ".join(attrs)}>')
                 xml_parts.append(f'    <description>{html.escape(description)}</description>')
                 xml_parts.append(f'  </search_result>')
+            elif snippet:
+                xml_parts.append(f'  <search_result {" ".join(attrs)}>')
+                xml_parts.append(f'    <content truncated="true">{html.escape(snippet)}</content>')
+                xml_parts.append(f'  </search_result>')
             else:
                 xml_parts.append(f'  <search_result {" ".join(attrs)} />')