fix(mcp): preserve empty all-project search scope

Signed-off-by: phernandez <paul@basicmachines.co>

Author: phernandez

src/basic_memory/mcp/tools/search.py

@@ -451,14 +451,23 @@ async def _search_all_projects(
     status: str | None,
     min_similarity: float | None,
     context: Context | None,
-) -> dict | str | None:
+) -> dict | str:
     """Search every accessible project when the caller explicitly opts in."""
+    requested_page = max(page, 1)
+    requested_page_size = max(page_size, 1)
     project_refs = await _load_search_project_refs(context=context)
     if not project_refs:
-        return None
+        response = SearchResponse(
+            results=[],
+            current_page=requested_page,
+            page_size=requested_page_size,
+            total=0,
+            has_more=False,
+        )
+        if output_format == "json":
+            return response.model_dump(mode="json", exclude_none=True)
+        return _format_search_markdown(response, "all projects", query)
 
-    requested_page = max(page, 1)
-    requested_page_size = max(page_size, 1)
     per_project_page_size = requested_page * requested_page_size
     merged_results: list[dict[str, Any]] = []
     total = 0
@@ -810,8 +819,7 @@ async def search_notes(
             min_similarity=min_similarity,
             context=context,
         )
-        if all_projects_result is not None:
-            return all_projects_result
+        return all_projects_result
 
     with logfire.span(
         "mcp.tool.search_notes",

tests/mcp/tools/test_search_notes_multi_project.py

@@ -131,3 +131,37 @@ async def search(self, payload, page, page_size):
     assert isinstance(result, dict)
     assert result["results"] == []
     assert searched_projects == [(None, None)]
+
+
+@pytest.mark.asyncio
+async def test_search_notes_search_all_projects_with_no_refs_returns_empty_all_projects(
+    monkeypatch,
+):
+    """Explicit all-project search must not silently fall back to one project."""
+    search_mod = importlib.import_module("basic_memory.mcp.tools.search")
+
+    async def fake_load_search_project_refs(context=None):
+        return []
+
+    @asynccontextmanager
+    async def fail_get_project_client(*args, **kwargs):
+        raise AssertionError("search_all_projects=True should not fall back to scoped search")
+        yield
+
+    monkeypatch.setattr(search_mod, "_load_search_project_refs", fake_load_search_project_refs)
+    monkeypatch.setattr(search_mod, "get_project_client", fail_get_project_client)
+
+    result = await search_mod.search_notes(
+        query="MCP Test Note",
+        search_all_projects=True,
+        output_format="json",
+    )
+
+    assert isinstance(result, dict)
+    assert result == {
+        "results": [],
+        "current_page": 1,
+        "page_size": 10,
+        "total": 0,
+        "has_more": False,
+    }