feat: add node coverage and improve investigation presentation

tests/unit/test_mcp_query.py

@@ -543,6 +543,42 @@ def test_evidence_is_saved_before_return_and_call_conflicts_fail(runtime, monkey
     assert len(saved) == 1
 
 
+def test_large_node_coverage_retains_publishable_hint_and_saves_complete_geometry(runtime, monkeypatch):
+    app, client, _, _ = runtime
+    value = binding(task=True)
+    saved = []
+    monkeypatch.setattr(application, "verify_task", AsyncMock())
+    monkeypatch.setattr(contexts, "verify_task", AsyncMock())
+
+    class TaskService:
+        repo = SimpleNamespace(lock=lambda key: asyncio.sleep(0))
+
+        async def record_data_snapshot(self, task_id, snapshot):
+            saved.append(snapshot)
+            return SimpleNamespace(evidence_id=snapshot.source_ref), snapshot
+
+    monkeypatch.setattr(application, "task_service", lambda scope: TaskService())
+    geometry = {"type": "FeatureCollection", "features": [{
+        "type": "Feature", "properties": {"label": "x" * 13000},
+        "geometry": {"type": "Polygon", "coordinates": [[[117, 32], [118, 32], [118, 33], [117, 32]]]},
+    }]}
+    app.executor = AsyncMock(return_value=QueryResult(
+        source="generate_node_coverage", source_ref="mcp:before-persisting", queried_at=datetime.now(timezone.utc),
+        semantics="analysis", data={"result": {"map_payload": geometry, "coverage": {
+            "status": "ready", "groups": {"compare": {"node_ids": ["A"], "mapped_node_count": 1}},
+        }}},
+    ))
+    output = request(client, "tools/call", {"name": "generate_node_coverage", "arguments": {
+        "context_handle": value.context_handle,
+        "groups": [{"group_id": "compare", "title": "节点比较", "node_ids": ["A"]}],
+    }}).json()["result"]["structuredContent"]
+    assert output["truncated"] is True
+    command = output["data"]["presentation"]["command"]
+    assert command["action"] == "set_overlay" and command["evidence_id"] == saved[0].source_ref
+    assert "data" not in command
+    assert saved[0].data["data"]["result"]["map_payload"] == geometry
+
+
 def test_business_skill_is_delivered_over_mcp_without_recording_event_evidence(runtime, monkeypatch):
     app, client, _, _ = runtime
     value = binding(task=True)