fix(hooks): prefer shared outbound conversation context

extensions/thread-ownership/index.test.ts

@@ -88,6 +88,30 @@ describe("thread-ownership plugin", () => {
       );
     });
 
+    it("prefers shared conversationId over non-canonical Slack target shapes", async () => {
+      vi.mocked(globalThis.fetch).mockResolvedValue(
+        new Response(JSON.stringify({ owner: "test-agent" }), { status: 200 }),
+      );
+
+      const result = await hooks.message_sending(
+        {
+          content: "hello",
+          replyToId: "1234.5678",
+          to: "channel:C123",
+        },
+        { channelId: "slack", conversationId: "C123" },
+      );
+
+      expect(result).toBeUndefined();
+      expect(globalThis.fetch).toHaveBeenCalledWith(
+        "http://localhost:8750/api/v1/ownership/C123/1234.5678",
+        expect.objectContaining({
+          method: "POST",
+          body: JSON.stringify({ agent_id: "test-agent" }),
+        }),
+      );
+    });
+
     it("cancels when thread owned by another agent", async () => {
       vi.mocked(globalThis.fetch).mockResolvedValue(
         new Response(JSON.stringify({ owner: "other-agent" }), { status: 409 }),

extensions/thread-ownership/index.ts

@@ -104,7 +104,11 @@ export default definePluginEntry({
         resolveThreadToken(event.threadId) ||
         resolveThreadToken(event.metadata?.threadId) ||
         resolveThreadToken(event.metadata?.threadTs);
-      const channelId = (event.metadata?.channelId as string) ?? event.to;
+      const channelId =
+        normalizeOptionalString(ctx.conversationId) ||
+        normalizeOptionalString(event.metadata?.channelId) ||
+        normalizeOptionalString(event.to) ||
+        "";
       if (!threadTs) {
         return undefined;
       }