Slack: reject blocks plus media in send paths

src/agents/tools/slack-actions.e2e.test.ts

@@ -221,6 +221,21 @@ describe("handleSlackAction", () => {
     ).rejects.toThrow(/requires content, blocks, or mediaUrl/i);
   });
 
+  it("rejects blocks combined with mediaUrl", async () => {
+    const cfg = { channels: { slack: { botToken: "tok" } } } as OpenClawConfig;
+    await expect(
+      handleSlackAction(
+        {
+          action: "sendMessage",
+          to: "channel:C123",
+          blocks: [{ type: "divider" }],
+          mediaUrl: "https://example.com/image.png",
+        },
+        cfg,
+      ),
+    ).rejects.toThrow(/does not support blocks with mediaUrl/i);
+  });
+
   it("passes blocks JSON to editSlackMessage with empty content", async () => {
     const cfg = { channels: { slack: { botToken: "tok" } } } as OpenClawConfig;
     editSlackMessage.mockClear();

src/agents/tools/slack-actions.ts

@@ -185,6 +185,9 @@ export async function handleSlackAction(
         if (!content && !mediaUrl && !blocks) {
           throw new Error("Slack sendMessage requires content, blocks, or mediaUrl.");
         }
+        if (mediaUrl && blocks) {
+          throw new Error("Slack sendMessage does not support blocks with mediaUrl.");
+        }
         const threadTs = resolveThreadTsFromContext(
           readStringParam(params, "threadTs"),
           to,