fix(slack): stop block-based sender rehydration on assistant message edits (#71700)

* fix(slack): stop block-based sender rehydration on message edits

* docs(changelog): note Slack sender attribution fix

CHANGELOG.md

@@ -187,6 +187,7 @@ Docs: https://docs.openclaw.ai
 - Sessions: make `sessions_spawn(mode="session")` errors name usable alternatives when the current channel cannot bind subagent threads. Fixes #67400. (#67790) Thanks @stainlu.
 - Agents/Claude CLI: pass the OpenClaw system prompt through Claude's prompt-file flag so Windows runs avoid argv length failures without changing system prompt semantics. Fixes #69158. (#69211) Thanks @skylee-01, @cassioanorte, @Syu0, and @Stache73.
 - Agents/CLI sessions: bind `google-gemini-cli` session auth-epoch to the Google account identity in `~/.gemini/oauth_creds.json`, so Gemini-backed agents resume their conversation after gateway restart instead of minting a fresh session, and stale bindings are invalidated when the authenticated Google account changes. Fixes #70973. (#71076) Thanks @openperf.
+- Slack: stop treating user mentions in assistant-authored message edit blocks as sender attribution, preventing edited bot messages from spoofing a mentioned DM user. (#71700) Thanks @vincentkoc.
 
 ## 2026.4.24
 

extensions/slack/src/monitor/events/messages.test.ts

@@ -271,6 +271,35 @@ describe("registerSlackMessageEvents", () => {
     expect(messageQueueMock).not.toHaveBeenCalled();
   });
 
+  it("drops self-authored message_changed events that only include block user IDs", async () => {
+    const { handleSlackMessage } = await invokeRegisteredHandler({
+      eventName: "message",
+      overrides: { dmPolicy: "open" },
+      event: {
+        ...makeAssistantChangedEvent(),
+        message: {
+          ts: "123.456",
+          user: "U_BOT",
+          text: "preview edit with mention",
+          blocks: [
+            {
+              type: "rich_text",
+              elements: [
+                {
+                  type: "rich_text_section",
+                  elements: [{ type: "user", user_id: "UREAL123" }],
+                },
+              ],
+            },
+          ],
+        },
+      },
+    });
+
+    expect(handleSlackMessage).not.toHaveBeenCalled();
+    expect(messageQueueMock).not.toHaveBeenCalled();
+  });
+
   it("handles channel and group messages via the unified message handler", async () => {
     const { handler, handleSlackMessage } = createHandlers("message", {
       dmPolicy: "open",

extensions/slack/src/monitor/events/messages.ts

@@ -59,31 +59,12 @@ function collectMetadataUserCandidates(
   }
 }
 
-function collectBlockUserIds(candidates: Set<string>, value: unknown, botUserId: string): void {
-  if (Array.isArray(value)) {
-    for (const entry of value) {
-      collectBlockUserIds(candidates, entry, botUserId);
-    }
-    return;
-  }
-  const record = asRecord(value);
-  if (!record) {
-    return;
-  }
-  addUserCandidate(candidates, record.user_id, botUserId);
-  for (const key of ["elements", "accessory", "fields"]) {
-    collectBlockUserIds(candidates, record[key], botUserId);
-  }
-}
-
 function resolveAssistantMessageChangedSender(params: {
-  event: SlackMessageChangedEvent;
   message?: SlackAssistantMessageRecord;
   botUserId: string;
 }): string | undefined {
   const candidates = new Set<string>();
   collectMetadataUserCandidates(candidates, params.message?.metadata, params.botUserId);
-  collectBlockUserIds(candidates, params.message?.blocks, params.botUserId);
   return candidates.size === 1 ? [...candidates][0] : undefined;
 }
 
@@ -122,7 +103,6 @@ function resolveAssistantMessageChangedInbound(params: {
     return undefined;
   }
   const senderId = resolveAssistantMessageChangedSender({
-    event: changed,
     message,
     botUserId: params.ctx.botUserId,
   });