fix(subagents): include tool role in subagent completion output

src/agents/subagent-announce.format.e2e.test.ts

@@ -232,6 +232,36 @@ describe("subagent announce formatting", () => {
     expect(msg).toContain("tool output line 1");
   });
 
+  it("falls back to latest tool output when assistant reply is empty", async () => {
+    const { runSubagentAnnounceFlow } = await import("./subagent-announce.js");
+    chatHistoryMock.mockResolvedValueOnce({
+      messages: [
+        {
+          role: "assistant",
+          content: [{ type: "text", text: "" }],
+        },
+        {
+          role: "tool",
+          content: [{ type: "text", text: "tool output line 2" }],
+        },
+      ],
+    });
+    readLatestAssistantReplyMock.mockResolvedValue("");
+
+    await runSubagentAnnounceFlow({
+      childSessionKey: "agent:main:subagent:worker",
+      childRunId: "run-tool-fallback-2",
+      requesterSessionKey: "agent:main:main",
+      requesterDisplayKey: "main",
+      ...defaultOutcomeAnnounce,
+      waitForCompletion: false,
+    });
+
+    const call = agentSpy.mock.calls[0]?.[0] as { params?: { message?: string } };
+    const msg = call?.params?.message as string;
+    expect(msg).toContain("tool output line 2");
+  });
+
   it("keeps full findings and includes compact stats", async () => {
     const { runSubagentAnnounceFlow } = await import("./subagent-announce.js");
     sessionStore = {

src/agents/subagent-announce.ts

@@ -37,6 +37,14 @@ type ToolResultMessage = {
   content?: unknown;
 };
 
+function isToolResultMessage(msg: unknown): boolean {
+  if (!msg || typeof msg !== "object") {
+    return false;
+  }
+  const role = (msg as { role?: unknown }).role;
+  return role === "toolResult" || role === "tool";
+}
+
 function extractToolResultText(content: unknown): string {
   if (typeof content === "string") {
     return sanitizeTextContent(content);
@@ -60,13 +68,10 @@ async function readLatestToolResult(sessionKey: string): Promise<string | undefi
   const messages = Array.isArray(history?.messages) ? history.messages : [];
   for (let i = messages.length - 1; i >= 0; i -= 1) {
     const msg = messages[i];
-    if (!msg || typeof msg !== "object") {
+    if (!isToolResultMessage(msg)) {
       continue;
     }
     const candidate = msg as ToolResultMessage;
-    if (candidate.role !== "toolResult") {
-      continue;
-    }
     const text = extractToolResultText(candidate.content);
     if (text) {
       return text;

src/agents/tools/sessions-helpers.ts

@@ -127,7 +127,7 @@ export function stripToolMessages(messages: unknown[]): unknown[] {
       return true;
     }
     const role = (msg as { role?: unknown }).role;
-    return role !== "toolResult";
+    return role !== "toolResult" && role !== "tool";
   });
 }