fix(regression): preserve session tool event metadata

src/gateway/server-chat.agent-events.test.ts

@@ -655,6 +655,21 @@ describe("agent event handler", () => {
       resolveSessionKeyForRun: () => "session-1",
     });
 
+    vi.mocked(loadGatewaySessionRow).mockReturnValue({
+      key: "session-1",
+      kind: "direct",
+      spawnedBy: "agent:main:main",
+      spawnedWorkspaceDir: "/tmp/subagent",
+      forkedFromParent: true,
+      spawnDepth: 2,
+      subagentRole: "orchestrator",
+      subagentControlScope: "children",
+      lastThreadId: 42,
+      fastMode: true,
+      verboseLevel: "on",
+      updatedAt: 1_200,
+    });
+
     registerAgentRunContext("run-session-tool", { sessionKey: "session-1", verboseLevel: "off" });
     sessionEventSubscribers.subscribe("conn-session");
 
@@ -677,6 +692,15 @@ describe("agent event handler", () => {
       expect.objectContaining({
         runId: "run-session-tool",
         sessionKey: "session-1",
+        spawnedBy: "agent:main:main",
+        spawnedWorkspaceDir: "/tmp/subagent",
+        forkedFromParent: true,
+        spawnDepth: 2,
+        subagentRole: "orchestrator",
+        subagentControlScope: "children",
+        lastThreadId: 42,
+        fastMode: true,
+        verboseLevel: "on",
         stream: "tool",
         ts: 1_234,
         data: expect.objectContaining({

src/gateway/server-chat.ts

@@ -780,7 +780,12 @@ export function createAgentEventHandler({
       if (sessionKey) {
         const sessionSubscribers = sessionEventSubscribers.getAll();
         if (sessionSubscribers.size > 0) {
-          broadcastToConnIds("session.tool", toolPayload, sessionSubscribers, { dropIfSlow: true });
+          broadcastToConnIds(
+            "session.tool",
+            { ...toolPayload, ...buildSessionEventSnapshot(sessionKey) },
+            sessionSubscribers,
+            { dropIfSlow: true },
+          );
         }
       }
     } else {