fix: lint and tool test

core/framework/graph/edge.py

@@ -761,4 +761,15 @@ class GraphSpec(BaseModel):
                     "GCU nodes must be declared as subagents of a parent node."
                 )
 
+        # All sub_agents references must point to registered nodes
+        all_node_ids = {n.id for n in self.nodes}
+        for node in self.nodes:
+            for sa_id in node.sub_agents or []:
+                if sa_id not in all_node_ids:
+                    errors.append(
+                        f"Node '{node.id}' references sub_agent '{sa_id}' "
+                        "which is not registered in the nodes list. "
+                        "Ensure the sub_agent node is included in the agent's nodes."
+                    )
+
         return {"errors": errors, "warnings": warnings}

core/tests/test_subagent_registration_validation.py

@@ -0,0 +1,104 @@
+"""
+Tests for sub_agents reference validation.
+
+Validates that all node IDs listed in a node's sub_agents field
+are actually registered in the graph's nodes list.
+"""
+
+from framework.graph.edge import GraphSpec
+from framework.graph.node import NodeSpec
+
+
+class TestSubAgentRegistrationValidation:
+    """sub_agents references to unregistered nodes must be rejected."""
+
+    def test_sub_agent_not_registered_fails(self):
+        """A node referencing a sub_agent that isn't in the nodes list -> error."""
+        graph = GraphSpec(
+            id="g1",
+            goal_id="goal1",
+            entry_node="main",
+            terminal_nodes=["main"],
+            nodes=[
+                NodeSpec(
+                    id="main",
+                    name="Main",
+                    description="Main node",
+                    sub_agents=["missing_gcu"],
+                ),
+            ],
+            edges=[],
+        )
+
+        errors = graph.validate()["errors"]
+        sa_errors = [e for e in errors if "not registered" in e]
+        assert len(sa_errors) == 1
+        assert "'missing_gcu'" in sa_errors[0]
+        assert "'main'" in sa_errors[0]
+
+    def test_sub_agent_registered_passes(self):
+        """A node referencing a sub_agent that exists in nodes -> no error."""
+        graph = GraphSpec(
+            id="g1",
+            goal_id="goal1",
+            entry_node="main",
+            terminal_nodes=["main"],
+            nodes=[
+                NodeSpec(
+                    id="main",
+                    name="Main",
+                    description="Main node",
+                    sub_agents=["helper"],
+                ),
+                NodeSpec(
+                    id="helper",
+                    name="Helper",
+                    description="Helper GCU node",
+                    node_type="gcu",
+                ),
+            ],
+            edges=[],
+        )
+
+        errors = graph.validate()["errors"]
+        sa_errors = [e for e in errors if "not registered" in e]
+        assert len(sa_errors) == 0
+
+    def test_multiple_unregistered_sub_agents(self):
+        """Multiple missing sub_agents -> one error per missing reference."""
+        graph = GraphSpec(
+            id="g1",
+            goal_id="goal1",
+            entry_node="main",
+            terminal_nodes=["main"],
+            nodes=[
+                NodeSpec(
+                    id="main",
+                    name="Main",
+                    description="Main node",
+                    sub_agents=["missing_a", "missing_b"],
+                ),
+            ],
+            edges=[],
+        )
+
+        errors = graph.validate()["errors"]
+        sa_errors = [e for e in errors if "not registered" in e]
+        assert len(sa_errors) == 2
+
+    def test_no_sub_agents_passes(self):
+        """A node with no sub_agents -> no error from this rule."""
+        graph = GraphSpec(
+            id="g1",
+            goal_id="goal1",
+            entry_node="main",
+            terminal_nodes=["main"],
+            nodes=[
+                NodeSpec(id="main", name="Main", description="Main node"),
+            ],
+            edges=[],
+        )
+
+        errors = graph.validate()["errors"]
+        sa_errors = [e for e in errors if "not registered" in e]
+        assert len(sa_errors) == 0

tools/tests/test_coder_tools_server.py

@@ -114,7 +114,7 @@ def test_list_agent_tools_groups_by_provider_and_keeps_uncredentialed(monkeypatc
     google_tools = {t["name"] for t in providers["google"]["tools"]}
     assert "gmail_list_messages" in google_tools
     assert "calendar_list_events" in google_tools
-    assert "send_email" in google_tools
+    assert "send_email" not in google_tools  # multi-provider tool, only in resend
     assert providers["google"]["authorization"]
 
     resend_tools = {t["name"] for t in providers["resend"]["tools"]}