fix(slack): preserve ack on pre-reply errors

extensions/slack/src/monitor.tool-result.test.ts

@@ -648,6 +648,57 @@ describe("monitorSlackProvider tool results", () => {
     });
   });
 
+  it("restores ack reaction when dispatch fails before any reply is delivered", async () => {
+    replyMock.mockRejectedValue(new Error("boom"));
+    slackTestState.config = {
+      messages: {
+        responsePrefix: "PFX",
+        ackReaction: "👀",
+        ackReactionScope: "group-mentions",
+        removeAckAfterReply: true,
+        statusReactions: {
+          enabled: true,
+          timing: { debounceMs: 0, doneHoldMs: 0, errorHoldMs: 0 },
+        },
+      },
+      channels: {
+        slack: {
+          dm: { enabled: true, policy: "open", allowFrom: ["*"] },
+          groupPolicy: "open",
+        },
+      },
+    };
+    const client = getSlackClient();
+    if (!client) {
+      throw new Error("Slack client not registered");
+    }
+    const conversations = client.conversations as {
+      info: ReturnType<typeof vi.fn>;
+    };
+    conversations.info.mockResolvedValueOnce({
+      channel: { name: "general", is_channel: true },
+    });
+
+    await runSlackMessageOnce(monitorSlackProvider, {
+      event: makeSlackMessageEvent({
+        text: "<@bot-user> hello",
+        ts: "456",
+        channel_type: "channel",
+      }),
+    });
+    await new Promise((resolve) => setTimeout(resolve, 0));
+    await flush();
+
+    expect(sendMock).not.toHaveBeenCalled();
+    expect(reactMock.mock.calls.map(([args]) => String((args as { name: string }).name))).toEqual([
+      "eyes",
+      "scream",
+      "eyes",
+      "eyes",
+      "scream",
+    ]);
+  });
+
   it("replies with pairing code when dmPolicy is pairing and no allowFrom is set", async () => {
     setPairingOnlyDirectMessages();
 

extensions/slack/src/monitor/message-handler/dispatch.ts

@@ -348,6 +348,7 @@ export async function dispatchPreparedSlackMessage(prepared: PreparedSlackMessag
   let streamSession: SlackStreamSession | null = null;
   let streamFailed = false;
   let usedReplyThreadTs: string | undefined;
+  let observedReplyDelivery = false;
 
   const deliverNormally = async (payload: ReplyPayload, forcedThreadTs?: string): Promise<void> => {
     const replyThreadTs = forcedThreadTs ?? replyPlan.nextThreadTs();
@@ -362,6 +363,7 @@ export async function dispatchPreparedSlackMessage(prepared: PreparedSlackMessag
       replyToMode: prepared.replyToMode,
       ...(slackIdentity ? { identity: slackIdentity } : {}),
     });
+    observedReplyDelivery = true;
     // Record the thread ts only after confirmed delivery success.
     if (replyThreadTs) {
       usedReplyThreadTs ??= replyThreadTs;
@@ -399,6 +401,7 @@ export async function dispatchPreparedSlackMessage(prepared: PreparedSlackMessag
           teamId: ctx.teamId,
           userId: message.user,
         });
+        observedReplyDelivery = true;
         usedReplyThreadTs ??= streamThreadTs;
         replyPlan.markSent();
         return;
@@ -455,6 +458,7 @@ export async function dispatchPreparedSlackMessage(prepared: PreparedSlackMessag
               ...(slackBlocks?.length ? { blocks: slackBlocks } : {}),
             },
           );
+          observedReplyDelivery = true;
           return;
         } catch (err) {
           logVerbose(
@@ -620,7 +624,8 @@ export async function dispatchPreparedSlackMessage(prepared: PreparedSlackMessag
     }
   }
 
-  const anyReplyDelivered = queuedFinal || (counts.block ?? 0) > 0 || (counts.final ?? 0) > 0;
+  const anyReplyDelivered =
+    observedReplyDelivery || queuedFinal || (counts.block ?? 0) > 0 || (counts.final ?? 0) > 0;
 
   if (statusReactionsEnabled) {
     if (dispatchError) {
@@ -628,7 +633,11 @@ export async function dispatchPreparedSlackMessage(prepared: PreparedSlackMessag
       if (ctx.removeAckAfterReply) {
         void (async () => {
           await sleep(statusReactionTiming.errorHoldMs);
-          await statusReactions.clear();
+          if (anyReplyDelivered) {
+            await statusReactions.clear();
+            return;
+          }
+          await statusReactions.restoreInitial();
         })();
       } else {
         void statusReactions.restoreInitial();