fix(slack): send block-only slash replies

CHANGELOG.md

@@ -32,6 +32,7 @@ Docs: https://docs.openclaw.ai
 - WhatsApp: stage `qrcode` through root mirrored runtime dependencies so packaged QR pairing can render from staged plugin-runtime-deps installs. Fixes #75394. Thanks @FelipeX2001.
 - Discord/voice: apply per-channel Discord `systemPrompt` overrides to voice transcript turns by forwarding the trusted channel prompt through the voice agent run. Fixes #47095. Thanks @qearlyao.
 - Discord/native commands: send component-only interaction replies from slash command and status handlers instead of treating renderable Discord components as an empty response. Thanks @vincentkoc.
+- Slack/slash commands: send block-only slash command replies instead of dropping Slack block payloads with no plain-text fallback. Thanks @vincentkoc.
 - Gateway/agent: reject strict `openclaw agent --deliver` requests with missing delivery targets before starting the agent run, so users do not wait for a completed turn that cannot send anywhere. Thanks @vincentkoc.
 - Setup/import: honor non-interactive `--import-from` onboarding flags by running the migration import path instead of silently completing normal setup without importing anything. Thanks @vincentkoc.
 - Discord/voice: run voice-channel turns under a voice-output policy that hides the agent `tts` tool and asks for spoken reply text, so `/vc join` sessions synthesize and play agent replies instead of ending with `NO_REPLY`. Fixes #61536. Thanks @aounakram.

extensions/slack/src/monitor/replies.test.ts

@@ -297,4 +297,31 @@ describe("deliverSlackSlashReplies chunking", () => {
       response_type: "ephemeral",
     });
   });
+
+  it("sends block-only slash replies instead of dropping them", async () => {
+    const respond = vi.fn(async () => undefined);
+    const blocks = [{ type: "divider" }];
+
+    await deliverSlackSlashReplies({
+      replies: [
+        {
+          channelData: {
+            slack: {
+              blocks,
+            },
+          },
+        },
+      ],
+      respond,
+      ephemeral: false,
+      textLimit: 8000,
+    });
+
+    expect(respond).toHaveBeenCalledTimes(1);
+    expect(respond).toHaveBeenCalledWith({
+      text: "",
+      blocks,
+      response_type: "in_channel",
+    });
+  });
 });

extensions/slack/src/monitor/replies.ts

@@ -116,6 +116,7 @@ export async function deliverReplies(params: {
 
 export type SlackRespondFn = (payload: {
   text: string;
+  blocks?: ReturnType<typeof readSlackReplyBlocks>;
   response_type?: "ephemeral" | "in_channel";
 }) => Promise<unknown>;
 
@@ -202,14 +203,19 @@ export async function deliverSlackSlashReplies(params: {
   tableMode?: MarkdownTableMode;
   chunkMode?: ChunkMode;
 }) {
-  const messages: string[] = [];
+  const messages: Array<{ text: string; blocks?: ReturnType<typeof readSlackReplyBlocks> }> = [];
   const chunkLimit = Math.min(params.textLimit, SLACK_TEXT_LIMIT);
   for (const payload of params.replies) {
     const reply = resolveSendableOutboundReplyParts(payload);
+    const slackBlocks = readSlackReplyBlocks(payload);
     const text =
       reply.hasText && !isSilentReplyText(reply.trimmedText, SILENT_REPLY_TOKEN)
         ? reply.trimmedText
         : undefined;
+    if (slackBlocks?.length && !reply.hasMedia) {
+      messages.push({ text: text ?? "", blocks: slackBlocks });
+      continue;
+    }
     const combined = [text ?? "", ...reply.mediaUrls].filter(Boolean).join("\n");
     if (!combined) {
       continue;
@@ -226,7 +232,7 @@ export async function deliverSlackSlashReplies(params: {
       chunks.push(combined);
     }
     for (const chunk of chunks) {
-      messages.push(chunk);
+      messages.push({ text: chunk });
     }
   }
 
@@ -236,7 +242,7 @@ export async function deliverSlackSlashReplies(params: {
 
   // Slack slash command responses can be multi-part by sending follow-ups via response_url.
   const responseType = params.ephemeral ? "ephemeral" : "in_channel";
-  for (const text of messages) {
-    await params.respond({ text, response_type: responseType });
+  for (const message of messages) {
+    await params.respond({ ...message, response_type: responseType });
   }
 }