diff --git a/src/agents/tools/message-tool.test.ts b/src/agents/tools/message-tool.test.ts
index 1a87e74ca0ec..e7edcb8b1e9e 100644
--- a/src/agents/tools/message-tool.test.ts
+++ b/src/agents/tools/message-tool.test.ts
@@ -1258,6 +1258,35 @@ describe("message tool explicit target guard", () => {
     expect(mocks.runMessageAction).not.toHaveBeenCalled();
   });
 
+  it.each([
+    {
+      action: "poll",
+      params: {
+        action: "poll",
+        pollQuestion: "Lunch?",
+        pollOption: ["Pizza", "Sushi"],
+      },
+    },
+    {
+      action: "sticker",
+      params: {
+        action: "sticker",
+        stickerId: "sticker-1",
+      },
+    },
+  ] as const)("requires an explicit target for $action when configured", async ({ params }) => {
+    const tool = createMessageTool({
+      runMessageAction: mocks.runMessageAction as never,
+      requireExplicitTarget: true,
+      currentChannelProvider: "slack",
+      currentChannelId: "channel:C123",
+    });
+
+    await expect(tool.execute("1", params)).rejects.toThrow(/Explicit message target required/i);
+
+    expect(mocks.runMessageAction).not.toHaveBeenCalled();
+  });
+
   it("allows upload-file when an explicit target is provided", async () => {
     mocks.runMessageAction.mockResolvedValueOnce({
       kind: "action",
diff --git a/src/agents/tools/message-tool.ts b/src/agents/tools/message-tool.ts
index 447698fe5ce1..ef779d6fd331 100644
--- a/src/agents/tools/message-tool.ts
+++ b/src/agents/tools/message-tool.ts
@@ -50,7 +50,10 @@ import {
   runMessageAction,
   type MessageActionRunResult,
 } from "../../infra/outbound/message-action-runner.js";
-import { resolveAllowedMessageActions } from "../../infra/outbound/outbound-policy.js";
+import {
+  resolveAllowedMessageActions,
+  shouldApplyCrossContextMarker,
+} from "../../infra/outbound/outbound-policy.js";
 import { hasReplyPayloadContent } from "../../interactive/payload.js";
 import { stringifyRouteThreadId } from "../../plugin-sdk/channel-route.js";
 import { POLL_CREATION_PARAM_DEFS, SHARED_POLL_CREATION_PARAM_NAMES } from "../../poll-params.js";
@@ -83,18 +86,8 @@ import {
 const AllMessageActions = CHANNEL_MESSAGE_ACTION_NAMES;
 const MESSAGE_TOOL_THREAD_READ_HINT =
   ' Use action="read" with threadId to fetch prior messages in a thread when you need conversation context you do not have yet.';
-const EXPLICIT_TARGET_ACTIONS = new Set<ChannelMessageActionName>([
-  "send",
-  "sendWithEffect",
-  "sendAttachment",
-  "upload-file",
-  "reply",
-  "thread-reply",
-  "broadcast",
-]);
-
 function actionNeedsExplicitTarget(action: ChannelMessageActionName): boolean {
-  return EXPLICIT_TARGET_ACTIONS.has(action);
+  return action === "broadcast" || shouldApplyCrossContextMarker(action);
 }
 
 function normalizeMessageToolIdempotencyKeyPart(value: unknown): string | undefined {