fix(slack): drop mismatched Socket Mode events (#889)

Filter Slack Socket Mode events by api_app_id/team_id.
Refs: #828
Contributor: @roshanasingh4

Co-authored-by: Roshan Singh <roshanasingh4@users.noreply.github.com>

CHANGELOG.md

@@ -10,6 +10,7 @@
 - macOS: fix cron preview/testing payload to use `channel` key. (#867) — thanks @wes-davis.
 - Telegram: honor `channels.telegram.timeoutSeconds` for grammY API requests. (#863) — thanks @Snaver.
 - Telegram: split long captions into media + follow-up text messages. (#907) - thanks @jalehman.
+- Slack: drop Socket Mode events with mismatched `api_app_id`/`team_id`. (#889) — thanks @roshanasingh4.
 
 ## 2026.1.13
 

src/slack/monitor.tool-result.sends-tool-summaries-responseprefix.test.ts

@@ -158,6 +158,46 @@ describe("monitorSlackProvider tool results", () => {
     expect(sendMock.mock.calls[1][1]).toBe("PFX final reply");
   });
 
+  it("drops events with mismatched api_app_id", async () => {
+    const client = getSlackClient();
+    if (!client) throw new Error("Slack client not registered");
+    (client.auth as { test: ReturnType<typeof vi.fn> }).test.mockResolvedValue({
+      user_id: "bot-user",
+      team_id: "T1",
+      api_app_id: "A1",
+    });
+
+    const controller = new AbortController();
+    const run = monitorSlackProvider({
+      botToken: "bot-token",
+      appToken: "xapp-1-A1-abc",
+      abortSignal: controller.signal,
+    });
+
+    await waitForEvent("message");
+    const handler = getSlackHandlers()?.get("message");
+    if (!handler) throw new Error("Slack message handler not registered");
+
+    await handler({
+      body: { api_app_id: "A2", team_id: "T1" },
+      event: {
+        type: "message",
+        user: "U1",
+        text: "hello",
+        ts: "123",
+        channel: "C1",
+        channel_type: "im",
+      },
+    });
+
+    await flush();
+    controller.abort();
+    await run;
+
+    expect(sendMock).not.toHaveBeenCalled();
+    expect(replyMock).not.toHaveBeenCalled();
+  });
+
   it("does not derive responsePrefix from routed agent identity when unset", async () => {
     config = {
       agents: {

src/slack/monitor/context.ts

@@ -22,6 +22,7 @@ export type SlackMonitorContext = {
 
   botUserId: string;
   teamId: string;
+  apiAppId: string;
 
   historyLimit: number;
   channelHistories: Map<string, HistoryEntry[]>;
@@ -58,6 +59,7 @@ export type SlackMonitorContext = {
 
   logger: ReturnType<typeof getChildLogger>;
   markMessageSeen: (channelId: string | undefined, ts?: string) => boolean;
+  shouldDropMismatchedSlackEvent: (body: unknown) => boolean;
   resolveSlackSystemEventSessionKey: (params: {
     channelId?: string | null;
     channelType?: string | null;
@@ -90,6 +92,7 @@ export function createSlackMonitorContext(params: {
 
   botUserId: string;
   teamId: string;
+  apiAppId: string;
 
   historyLimit: number;
   sessionScope: SessionScope;
@@ -290,6 +293,25 @@ export function createSlackMonitorContext(params: {
     return true;
   };
 
+  const shouldDropMismatchedSlackEvent = (body: unknown) => {
+    if (!body || typeof body !== "object") return false;
+    const raw = body as { api_app_id?: unknown; team_id?: unknown };
+    const incomingApiAppId = typeof raw.api_app_id === "string" ? raw.api_app_id : "";
+    const incomingTeamId = typeof raw.team_id === "string" ? raw.team_id : "";
+
+    if (params.apiAppId && incomingApiAppId && incomingApiAppId !== params.apiAppId) {
+      logVerbose(
+        `slack: drop event with api_app_id=${incomingApiAppId} (expected ${params.apiAppId})`,
+      );
+      return true;
+    }
+    if (params.teamId && incomingTeamId && incomingTeamId !== params.teamId) {
+      logVerbose(`slack: drop event with team_id=${incomingTeamId} (expected ${params.teamId})`);
+      return true;
+    }
+    return false;
+  };
+
   return {
     cfg: params.cfg,
     accountId: params.accountId,
@@ -298,6 +320,7 @@ export function createSlackMonitorContext(params: {
     runtime: params.runtime,
     botUserId: params.botUserId,
     teamId: params.teamId,
+    apiAppId: params.apiAppId,
     historyLimit: params.historyLimit,
     channelHistories,
     sessionScope: params.sessionScope,
@@ -320,6 +343,7 @@ export function createSlackMonitorContext(params: {
     removeAckAfterReply: params.removeAckAfterReply,
     logger,
     markMessageSeen,
+    shouldDropMismatchedSlackEvent,
     resolveSlackSystemEventSessionKey,
     isChannelAllowed,
     resolveChannelName,

src/slack/monitor/events/channels.ts

@@ -12,8 +12,10 @@ export function registerSlackChannelEvents(params: { ctx: SlackMonitorContext })
 
   ctx.app.event(
     "channel_created",
-    async ({ event }: SlackEventMiddlewareArgs<"channel_created">) => {
+    async ({ event, body }: SlackEventMiddlewareArgs<"channel_created">) => {
       try {
+        if (ctx.shouldDropMismatchedSlackEvent(body)) return;
+
         const payload = event as SlackChannelCreatedEvent;
         const channelId = payload.channel?.id;
         const channelName = payload.channel?.name;
@@ -41,31 +43,36 @@ export function registerSlackChannelEvents(params: { ctx: SlackMonitorContext })
     },
   );
 
-  ctx.app.event("channel_rename", async ({ event }: SlackEventMiddlewareArgs<"channel_rename">) => {
-    try {
-      const payload = event as SlackChannelRenamedEvent;
-      const channelId = payload.channel?.id;
-      const channelName = payload.channel?.name_normalized ?? payload.channel?.name;
-      if (
-        !ctx.isChannelAllowed({
+  ctx.app.event(
+    "channel_rename",
+    async ({ event, body }: SlackEventMiddlewareArgs<"channel_rename">) => {
+      try {
+        if (ctx.shouldDropMismatchedSlackEvent(body)) return;
+
+        const payload = event as SlackChannelRenamedEvent;
+        const channelId = payload.channel?.id;
+        const channelName = payload.channel?.name_normalized ?? payload.channel?.name;
+        if (
+          !ctx.isChannelAllowed({
+            channelId,
+            channelName,
+            channelType: "channel",
+          })
+        ) {
+          return;
+        }
+        const label = resolveSlackChannelLabel({ channelId, channelName });
+        const sessionKey = ctx.resolveSlackSystemEventSessionKey({
           channelId,
-          channelName,
           channelType: "channel",
-        })
-      ) {
-        return;
+        });
+        enqueueSystemEvent(`Slack channel renamed: ${label}.`, {
+          sessionKey,
+          contextKey: `slack:channel:renamed:${channelId ?? channelName ?? "unknown"}`,
+        });
+      } catch (err) {
+        ctx.runtime.error?.(danger(`slack channel rename handler failed: ${String(err)}`));
       }
-      const label = resolveSlackChannelLabel({ channelId, channelName });
-      const sessionKey = ctx.resolveSlackSystemEventSessionKey({
-        channelId,
-        channelType: "channel",
-      });
-      enqueueSystemEvent(`Slack channel renamed: ${label}.`, {
-        sessionKey,
-        contextKey: `slack:channel:renamed:${channelId ?? channelName ?? "unknown"}`,
-      });
-    } catch (err) {
-      ctx.runtime.error?.(danger(`slack channel rename handler failed: ${String(err)}`));
-    }
-  });
+    },
+  );
 }

src/slack/monitor/events/members.ts

@@ -12,8 +12,9 @@ export function registerSlackMemberEvents(params: { ctx: SlackMonitorContext })
 
   ctx.app.event(
     "member_joined_channel",
-    async ({ event }: SlackEventMiddlewareArgs<"member_joined_channel">) => {
+    async ({ event, body }: SlackEventMiddlewareArgs<"member_joined_channel">) => {
       try {
+        if (ctx.shouldDropMismatchedSlackEvent(body)) return;
         const payload = event as SlackMemberChannelEvent;
         const channelId = payload.channel;
         const channelInfo = channelId ? await ctx.resolveChannelName(channelId) : {};
@@ -49,8 +50,9 @@ export function registerSlackMemberEvents(params: { ctx: SlackMonitorContext })
 
   ctx.app.event(
     "member_left_channel",
-    async ({ event }: SlackEventMiddlewareArgs<"member_left_channel">) => {
+    async ({ event, body }: SlackEventMiddlewareArgs<"member_left_channel">) => {
       try {
+        if (ctx.shouldDropMismatchedSlackEvent(body)) return;
         const payload = event as SlackMemberChannelEvent;
         const channelId = payload.channel;
         const channelInfo = channelId ? await ctx.resolveChannelName(channelId) : {};

src/slack/monitor/events/messages.ts

@@ -19,8 +19,10 @@ export function registerSlackMessageEvents(params: {
 }) {
   const { ctx, handleSlackMessage } = params;
 
-  ctx.app.event("message", async ({ event }: SlackEventMiddlewareArgs<"message">) => {
+  ctx.app.event("message", async ({ event, body }: SlackEventMiddlewareArgs<"message">) => {
     try {
+      if (ctx.shouldDropMismatchedSlackEvent(body)) return;
+
       const message = event as SlackMessageEvent;
       if (message.subtype === "message_changed") {
         const changed = event as SlackMessageChangedEvent;
@@ -108,14 +110,17 @@ export function registerSlackMessageEvents(params: {
         });
         return;
       }
+
       await handleSlackMessage(message, { source: "message" });
     } catch (err) {
       ctx.runtime.error?.(danger(`slack handler failed: ${String(err)}`));
     }
   });
 
-  ctx.app.event("app_mention", async ({ event }: SlackEventMiddlewareArgs<"app_mention">) => {
+  ctx.app.event("app_mention", async ({ event, body }: SlackEventMiddlewareArgs<"app_mention">) => {
     try {
+      if (ctx.shouldDropMismatchedSlackEvent(body)) return;
+
       const mention = event as SlackAppMentionEvent;
       await handleSlackMessage(mention as unknown as SlackMessageEvent, {
         source: "app_mention",

src/slack/monitor/events/pins.ts

@@ -10,8 +10,10 @@ import type { SlackPinEvent } from "../types.js";
 export function registerSlackPinEvents(params: { ctx: SlackMonitorContext }) {
   const { ctx } = params;
 
-  ctx.app.event("pin_added", async ({ event }: SlackEventMiddlewareArgs<"pin_added">) => {
+  ctx.app.event("pin_added", async ({ event, body }: SlackEventMiddlewareArgs<"pin_added">) => {
     try {
+      if (ctx.shouldDropMismatchedSlackEvent(body)) return;
+
       const payload = event as SlackPinEvent;
       const channelId = payload.channel_id;
       const channelInfo = channelId ? await ctx.resolveChannelName(channelId) : {};
@@ -45,8 +47,10 @@ export function registerSlackPinEvents(params: { ctx: SlackMonitorContext }) {
     }
   });
 
-  ctx.app.event("pin_removed", async ({ event }: SlackEventMiddlewareArgs<"pin_removed">) => {
+  ctx.app.event("pin_removed", async ({ event, body }: SlackEventMiddlewareArgs<"pin_removed">) => {
     try {
+      if (ctx.shouldDropMismatchedSlackEvent(body)) return;
+
       const payload = event as SlackPinEvent;
       const channelId = payload.channel_id;
       const channelInfo = channelId ? await ctx.resolveChannelName(channelId) : {};

src/slack/monitor/events/reactions.ts

@@ -3,65 +3,37 @@ import type { SlackEventMiddlewareArgs } from "@slack/bolt";
 import { danger } from "../../../globals.js";
 import { enqueueSystemEvent } from "../../../infra/system-events.js";
 
-import { normalizeSlackSlug } from "../allow-list.js";
-import {
-  resolveSlackChannelConfig,
-  shouldEmitSlackReactionNotification,
-} from "../channel-config.js";
+import { resolveSlackChannelLabel } from "../channel-config.js";
 import type { SlackMonitorContext } from "../context.js";
-import type { SlackReactionEvent } from "../types.js";
+import type { SlackMessageEvent, SlackReactionEvent } from "../types.js";
 
 export function registerSlackReactionEvents(params: { ctx: SlackMonitorContext }) {
   const { ctx } = params;
 
-  const handleReactionEvent = async (event: SlackReactionEvent, action: "added" | "removed") => {
+  const handleReactionEvent = async (event: SlackReactionEvent, action: string) => {
     try {
       const item = event.item;
-      if (!event.user) return;
-      if (!item?.channel || !item?.ts) return;
-      if (item.type && item.type !== "message") return;
-      if (ctx.botUserId && event.user === ctx.botUserId) return;
-
-      const channelInfo = await ctx.resolveChannelName(item.channel);
-      const channelType = channelInfo?.type;
-      const channelName = channelInfo?.name;
+      if (!item || item.type !== "message") return;
 
+      const channelInfo = item.channel ? await ctx.resolveChannelName(item.channel) : {};
+      const channelType = channelInfo?.type as SlackMessageEvent["channel_type"];
       if (
         !ctx.isChannelAllowed({
           channelId: item.channel,
-          channelName,
+          channelName: channelInfo?.name,
           channelType,
         })
       ) {
         return;
       }
 
-      const isRoom = channelType === "channel" || channelType === "group";
-      if (isRoom) {
-        const channelConfig = resolveSlackChannelConfig({
-          channelId: item.channel,
-          channelName,
-          channels: ctx.channelsConfig,
-        });
-        if (channelConfig?.allowed === false) return;
-      }
-
-      const actor = await ctx.resolveUserName(event.user);
-      const shouldNotify = shouldEmitSlackReactionNotification({
-        mode: ctx.reactionMode,
-        botId: ctx.botUserId,
-        messageAuthorId: event.item_user ?? undefined,
-        userId: event.user,
-        userName: actor?.name ?? undefined,
-        allowlist: ctx.reactionAllowlist,
+      const channelLabel = resolveSlackChannelLabel({
+        channelId: item.channel,
+        channelName: channelInfo?.name,
       });
-      if (!shouldNotify) return;
-
+      const actorInfo = event.user ? await ctx.resolveUserName(event.user) : undefined;
+      const actorLabel = actorInfo?.name ?? event.user;
       const emojiLabel = event.reaction ?? "emoji";
-      const actorLabel = actor?.name ?? event.user;
-      const channelLabel = channelName
-        ? `#${normalizeSlackSlug(channelName) || channelName}`
-        : `#${item.channel}`;
       const authorInfo = event.item_user ? await ctx.resolveUserName(event.item_user) : undefined;
       const authorLabel = authorInfo?.name ?? event.item_user;
       const baseText = `Slack reaction ${action}: :${emojiLabel}: by ${actorLabel} in ${channelLabel} msg ${item.ts}`;
@@ -79,13 +51,18 @@ export function registerSlackReactionEvents(params: { ctx: SlackMonitorContext }
     }
   };
 
-  ctx.app.event("reaction_added", async ({ event }: SlackEventMiddlewareArgs<"reaction_added">) => {
-    await handleReactionEvent(event as SlackReactionEvent, "added");
-  });
+  ctx.app.event(
+    "reaction_added",
+    async ({ event, body }: SlackEventMiddlewareArgs<"reaction_added">) => {
+      if (ctx.shouldDropMismatchedSlackEvent(body)) return;
+      await handleReactionEvent(event as SlackReactionEvent, "added");
+    },
+  );
 
   ctx.app.event(
     "reaction_removed",
-    async ({ event }: SlackEventMiddlewareArgs<"reaction_removed">) => {
+    async ({ event, body }: SlackEventMiddlewareArgs<"reaction_removed">) => {
+      if (ctx.shouldDropMismatchedSlackEvent(body)) return;
       await handleReactionEvent(event as SlackReactionEvent, "removed");
     },
   );

src/slack/monitor/provider.ts

@@ -18,6 +18,13 @@ import { registerSlackMonitorSlashCommands } from "./slash.js";
 
 import type { MonitorSlackOpts } from "./types.js";
 
+function parseApiAppIdFromAppToken(raw?: string) {
+  const token = raw?.trim();
+  if (!token) return undefined;
+  const match = /^xapp-\d-([a-z0-9]+)-/i.exec(token);
+  return match?.[1]?.toUpperCase();
+}
+
 export async function monitorSlackProvider(opts: MonitorSlackOpts = {}) {
   const cfg = opts.config ?? loadConfig();
 
@@ -81,14 +88,23 @@ export async function monitorSlackProvider(opts: MonitorSlackOpts = {}) {
 
   let botUserId = "";
   let teamId = "";
+  let apiAppId = "";
+  const expectedApiAppIdFromAppToken = parseApiAppIdFromAppToken(appToken);
   try {
     const auth = await app.client.auth.test({ token: botToken });
     botUserId = auth.user_id ?? "";
     teamId = auth.team_id ?? "";
+    apiAppId = (auth as { api_app_id?: string }).api_app_id ?? "";
   } catch {
     // auth test failing is non-fatal; message handler falls back to regex mentions.
   }
 
+  if (apiAppId && expectedApiAppIdFromAppToken && apiAppId !== expectedApiAppIdFromAppToken) {
+    runtime.error?.(
+      `slack token mismatch: bot token api_app_id=${apiAppId} but app token looks like api_app_id=${expectedApiAppIdFromAppToken}`,
+    );
+  }
+
   const ctx = createSlackMonitorContext({
     cfg,
     accountId: account.accountId,
@@ -97,6 +113,7 @@ export async function monitorSlackProvider(opts: MonitorSlackOpts = {}) {
     runtime,
     botUserId,
     teamId,
+    apiAppId,
     historyLimit,
     sessionScope,
     mainKey,