fix: prevent delivery-mirror re-delivery and raise Slack chunk limit (#45489)

Merged via squash.

Prepared head SHA: c7664c7b6e
Co-authored-by: theo674 <261068216+theo674@users.noreply.github.com>
Co-authored-by: altaywtf <9790196+altaywtf@users.noreply.github.com>
Reviewed-by: @altaywtf

extensions/slack/src/channel.test.ts

@@ -192,6 +192,11 @@ describe("slackPlugin outbound", () => {
     },
   };
 
+  it("advertises the 8000-character Slack default chunk limit", () => {
+    expect(slackOutbound.textChunkLimit).toBe(8000);
+    expect(slackPlugin.outbound?.textChunkLimit).toBe(8000);
+  });
+
   it("uses threadId as threadTs fallback for sendText", async () => {
     const sendSlack = vi.fn().mockResolvedValue({ messageId: "m-text" });
     const sendText = requireSlackSendText();

extensions/slack/src/channel.ts

@@ -46,6 +46,7 @@ import {
 } from "./directory-config.js";
 import { resolveSlackGroupRequireMention, resolveSlackGroupToolPolicy } from "./group-policy.js";
 import { isSlackInteractiveRepliesEnabled } from "./interactive-replies.js";
+import { SLACK_TEXT_LIMIT } from "./limits.js";
 import { normalizeAllowListLower } from "./monitor/allow-list.js";
 import type { SlackProbe } from "./probe.js";
 import { resolveSlackUserAllowlist } from "./resolve-users.js";
@@ -602,7 +603,7 @@ export const slackPlugin: ChannelPlugin<ResolvedSlackAccount, SlackProbe> = crea
     base: {
       deliveryMode: "direct",
       chunker: null,
-      textChunkLimit: 4000,
+      textChunkLimit: SLACK_TEXT_LIMIT,
     },
     attachedResults: {
       channel: "slack",

extensions/slack/src/draft-stream.test.ts

@@ -98,6 +98,24 @@ describe("createSlackDraftStream", () => {
     expect(warn).toHaveBeenCalledTimes(1);
   });
 
+  it("allows a 4205-character preview with the default max chars", async () => {
+    const { stream, send, warn } = createDraftStreamHarness();
+    const text = "a".repeat(4205);
+
+    stream.update(text);
+    await stream.flush();
+
+    expect(send).toHaveBeenCalledTimes(1);
+    expect(send).toHaveBeenCalledWith(
+      "channel:C123",
+      text,
+      expect.objectContaining({
+        token: "xoxb-test",
+      }),
+    );
+    expect(warn).not.toHaveBeenCalled();
+  });
+
   it("clear removes preview message when one exists", async () => {
     const { stream, remove } = createDraftStreamHarness();
 

extensions/slack/src/draft-stream.ts

@@ -1,8 +1,8 @@
 import { createDraftStreamLoop } from "openclaw/plugin-sdk/channel-lifecycle";
 import { deleteSlackMessage, editSlackMessage } from "./actions.js";
+import { SLACK_TEXT_LIMIT } from "./limits.js";
 import { sendMessageSlack } from "./send.js";
 
-const SLACK_STREAM_MAX_CHARS = 4000;
 const DEFAULT_THROTTLE_MS = 1000;
 
 export type SlackDraftStream = {
@@ -29,7 +29,7 @@ export function createSlackDraftStream(params: {
   edit?: typeof editSlackMessage;
   remove?: typeof deleteSlackMessage;
 }): SlackDraftStream {
-  const maxChars = Math.min(params.maxChars ?? SLACK_STREAM_MAX_CHARS, SLACK_STREAM_MAX_CHARS);
+  const maxChars = Math.min(params.maxChars ?? SLACK_TEXT_LIMIT, SLACK_TEXT_LIMIT);
   const throttleMs = Math.max(250, params.throttleMs ?? DEFAULT_THROTTLE_MS);
   const send = params.send ?? sendMessageSlack;
   const edit = params.edit ?? editSlackMessage;

extensions/slack/src/limits.ts

@@ -0,0 +1 @@
+export const SLACK_TEXT_LIMIT = 8000;

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

@@ -17,6 +17,7 @@ import { resolvePinnedMainDmOwnerFromAllowlist } from "openclaw/plugin-sdk/secur
 import { editSlackMessage, reactSlackMessage, removeSlackReaction } from "../../actions.js";
 import { createSlackDraftStream } from "../../draft-stream.js";
 import { normalizeSlackOutboundText } from "../../format.js";
+import { SLACK_TEXT_LIMIT } from "../../limits.js";
 import { recordSlackThreadParticipation } from "../../sent-thread-cache.js";
 import {
   applyAppendOnlyStreamUpdate,
@@ -375,7 +376,7 @@ export async function dispatchPreparedSlackMessage(prepared: PreparedSlackMessag
     target: prepared.replyTarget,
     token: ctx.botToken,
     accountId: account.accountId,
-    maxChars: Math.min(ctx.textLimit, 4000),
+    maxChars: Math.min(ctx.textLimit, SLACK_TEXT_LIMIT),
     resolveThreadTs: () => {
       const ts = replyPlan.nextThreadTs();
       if (ts) {

extensions/slack/src/monitor/provider.ts

@@ -28,6 +28,7 @@ import { normalizeStringEntries } from "openclaw/plugin-sdk/text-runtime";
 import { resolveSlackAccount } from "../accounts.js";
 import { resolveSlackWebClientOptions } from "../client.js";
 import { normalizeSlackWebhookPath, registerSlackHttpHandler } from "../http/index.js";
+import { SLACK_TEXT_LIMIT } from "../limits.js";
 import { resolveSlackChannelAllowlist } from "../resolve-channels.js";
 import { resolveSlackUserAllowlist } from "../resolve-users.js";
 import { resolveSlackAppToken, resolveSlackBotToken } from "../token.js";
@@ -242,7 +243,9 @@ export async function monitorSlackProvider(opts: MonitorSlackOpts = {}) {
   const threadHistoryScope = slackCfg.thread?.historyScope ?? "thread";
   const threadInheritParent = slackCfg.thread?.inheritParent ?? false;
   const slashCommand = resolveSlackSlashCommandConfig(opts.slashCommand ?? slackCfg.slashCommand);
-  const textLimit = resolveTextChunkLimit(cfg, "slack", account.accountId);
+  const textLimit = resolveTextChunkLimit(cfg, "slack", account.accountId, {
+    fallbackLimit: SLACK_TEXT_LIMIT,
+  });
   const ackReactionScope = cfg.messages?.ackReactionScope ?? "group-mentions";
   const typingReaction = slackCfg.typingReaction?.trim() ?? "";
   const mediaMaxBytes = (opts.mediaMaxMb ?? slackCfg.mediaMaxMb ?? 20) * 1024 * 1024;

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

@@ -6,6 +6,7 @@ vi.mock("../send.js", () => ({
 }));
 
 let deliverReplies: typeof import("./replies.js").deliverReplies;
+import { deliverSlackSlashReplies } from "./replies.js";
 
 function baseParams(overrides?: Record<string, unknown>) {
   return {
@@ -97,3 +98,23 @@ describe("deliverReplies identity passthrough", () => {
     );
   });
 });
+
+describe("deliverSlackSlashReplies chunking", () => {
+  it("keeps a 4205-character reply in a single slash response by default", async () => {
+    const respond = vi.fn(async () => undefined);
+    const text = "a".repeat(4205);
+
+    await deliverSlackSlashReplies({
+      replies: [{ text }],
+      respond,
+      ephemeral: true,
+      textLimit: 8000,
+    });
+
+    expect(respond).toHaveBeenCalledTimes(1);
+    expect(respond).toHaveBeenCalledWith({
+      text,
+      response_type: "ephemeral",
+    });
+  });
+});

extensions/slack/src/monitor/replies.ts

@@ -11,6 +11,7 @@ import type { ReplyPayload } from "openclaw/plugin-sdk/reply-runtime";
 import type { RuntimeEnv } from "openclaw/plugin-sdk/runtime-env";
 import { parseSlackBlocksInput } from "../blocks-input.js";
 import { markdownToSlackMrkdwnChunks } from "../format.js";
+import { SLACK_TEXT_LIMIT } from "../limits.js";
 import { sendMessageSlack, type SlackSendIdentity } from "../send.js";
 
 export function readSlackReplyBlocks(payload: ReplyPayload) {
@@ -188,7 +189,7 @@ export async function deliverSlackSlashReplies(params: {
   chunkMode?: ChunkMode;
 }) {
   const messages: string[] = [];
-  const chunkLimit = Math.min(params.textLimit, 4000);
+  const chunkLimit = Math.min(params.textLimit, SLACK_TEXT_LIMIT);
   for (const payload of params.replies) {
     const reply = resolveSendableOutboundReplyParts(payload);
     const text =

extensions/slack/src/outbound-adapter.ts

@@ -19,6 +19,7 @@ import {
 } from "openclaw/plugin-sdk/reply-payload";
 import { parseSlackBlocksInput } from "./blocks-input.js";
 import { buildSlackInteractiveBlocks, type SlackBlock } from "./blocks-render.js";
+import { SLACK_TEXT_LIMIT } from "./limits.js";
 import { sendMessageSlack, type SlackSendIdentity } from "./send.js";
 
 const SLACK_MAX_BLOCKS = 50;
@@ -149,7 +150,7 @@ function resolveSlackBlocks(payload: {
 export const slackOutbound: ChannelOutboundAdapter = {
   deliveryMode: "direct",
   chunker: null,
-  textChunkLimit: 4000,
+  textChunkLimit: SLACK_TEXT_LIMIT,
   sendPayload: async (ctx) => {
     const payload = {
       ...ctx.payload,

extensions/slack/src/send.blocks.test.ts

@@ -50,6 +50,26 @@ describe("sendMessageSlack NO_REPLY guard", () => {
   });
 });
 
+describe("sendMessageSlack chunking", () => {
+  it("keeps 4205-character text in a single Slack post by default", async () => {
+    const client = createSlackSendTestClient();
+    const message = "a".repeat(4205);
+
+    await sendMessageSlack("channel:C123", message, {
+      token: "xoxb-test",
+      client,
+    });
+
+    expect(client.chat.postMessage).toHaveBeenCalledTimes(1);
+    expect(client.chat.postMessage).toHaveBeenCalledWith(
+      expect.objectContaining({
+        channel: "C123",
+        text: message,
+      }),
+    );
+  });
+});
+
 describe("sendMessageSlack blocks", () => {
   it("posts blocks with fallback text when message is empty", async () => {
     const client = createSlackSendTestClient();

extensions/slack/src/send.ts

@@ -20,10 +20,9 @@ import { buildSlackBlocksFallbackText } from "./blocks-fallback.js";
 import { validateSlackBlocksArray } from "./blocks-input.js";
 import { createSlackWebClient } from "./client.js";
 import { markdownToSlackMrkdwnChunks } from "./format.js";
+import { SLACK_TEXT_LIMIT } from "./limits.js";
 import { parseSlackTarget } from "./targets.js";
 import { resolveSlackBotToken } from "./token.js";
-
-const SLACK_TEXT_LIMIT = 4000;
 const SLACK_UPLOAD_SSRF_POLICY = {
   allowedHostnames: ["*.slack.com", "*.slack-edge.com", "*.slack-files.com"],
   allowRfc2544BenchmarkRange: true,
@@ -296,7 +295,9 @@ export async function sendMessageSlack(
       channelId,
     };
   }
-  const textLimit = resolveTextChunkLimit(cfg, "slack", account.accountId);
+  const textLimit = resolveTextChunkLimit(cfg, "slack", account.accountId, {
+    fallbackLimit: SLACK_TEXT_LIMIT,
+  });
   const chunkLimit = Math.min(textLimit, SLACK_TEXT_LIMIT);
   const tableMode = resolveMarkdownTableMode({
     cfg,