From 18652d181b47732c7389391da56e7536656e5cf4 Mon Sep 17 00:00:00 2001
From: Iranb <49674669+Iranb@users.noreply.github.com>
Date: Wed, 4 Feb 2026 19:31:35 +0800
Subject: [PATCH] fix(imessage): detect self-chat echoes to prevent infinite
 loops (#8680)

---
 src/imessage/monitor/deliver.ts          | 14 +++++-
 src/imessage/monitor/monitor-provider.ts | 58 ++++++++++++++++++++++++
 2 files changed, 71 insertions(+), 1 deletion(-)

diff --git a/src/imessage/monitor/deliver.ts b/src/imessage/monitor/deliver.ts
index eb5b72dd3..b39d68a6b 100644
--- a/src/imessage/monitor/deliver.ts
+++ b/src/imessage/monitor/deliver.ts
@@ -7,6 +7,10 @@ import { resolveMarkdownTableMode } from "../../config/markdown-tables.js";
 import { convertMarkdownTables } from "../../markdown/tables.js";
 import { sendMessageIMessage } from "../send.js";
 
+type SentMessageCache = {
+  remember: (scope: string, text: string) => void;
+};
+
 export async function deliverReplies(params: {
   replies: ReplyPayload[];
   target: string;
@@ -15,8 +19,11 @@ export async function deliverReplies(params: {
   runtime: RuntimeEnv;
   maxBytes: number;
   textLimit: number;
+  sentMessageCache?: SentMessageCache;
 }) {
-  const { replies, target, client, runtime, maxBytes, textLimit, accountId } = params;
+  const { replies, target, client, runtime, maxBytes, textLimit, accountId, sentMessageCache } =
+    params;
+  const scope = `${accountId ?? ""}:${target}`;
   const cfg = loadConfig();
   const tableMode = resolveMarkdownTableMode({
     cfg,
@@ -32,12 +39,14 @@ export async function deliverReplies(params: {
       continue;
     }
     if (mediaList.length === 0) {
+      sentMessageCache?.remember(scope, text);
       for (const chunk of chunkTextWithMode(text, textLimit, chunkMode)) {
         await sendMessageIMessage(target, chunk, {
           maxBytes,
           client,
           accountId,
         });
+        sentMessageCache?.remember(scope, chunk);
       }
     } else {
       let first = true;
@@ -50,6 +59,9 @@ export async function deliverReplies(params: {
           client,
           accountId,
         });
+        if (caption) {
+          sentMessageCache?.remember(scope, caption);
+        }
       }
     }
     runtime.log?.(`imessage: delivered reply to ${target}`);
diff --git a/src/imessage/monitor/monitor-provider.ts b/src/imessage/monitor/monitor-provider.ts
index 9044f221b..bb2123e0c 100644
--- a/src/imessage/monitor/monitor-provider.ts
+++ b/src/imessage/monitor/monitor-provider.ts
@@ -111,6 +111,51 @@ function describeReplyContext(message: IMessagePayload): IMessageReplyContext |
   return { body, id, sender };
 }
 
+/**
+ * Cache for recently sent messages, used for echo detection.
+ * Keys are scoped by conversation (accountId:target) so the same text in different chats is not conflated.
+ * Entries expire after 5 seconds; we do not forget on match so multiple echo deliveries are all filtered.
+ */
+class SentMessageCache {
+  private cache = new Map<string, number>();
+  private readonly ttlMs = 5000; // 5 seconds
+
+  remember(scope: string, text: string): void {
+    if (!text?.trim()) {
+      return;
+    }
+    const key = `${scope}:${text.trim()}`;
+    this.cache.set(key, Date.now());
+    this.cleanup();
+  }
+
+  has(scope: string, text: string): boolean {
+    if (!text?.trim()) {
+      return false;
+    }
+    const key = `${scope}:${text.trim()}`;
+    const timestamp = this.cache.get(key);
+    if (!timestamp) {
+      return false;
+    }
+    const age = Date.now() - timestamp;
+    if (age > this.ttlMs) {
+      this.cache.delete(key);
+      return false;
+    }
+    return true;
+  }
+
+  private cleanup(): void {
+    const now = Date.now();
+    for (const [text, timestamp] of this.cache.entries()) {
+      if (now - timestamp > this.ttlMs) {
+        this.cache.delete(text);
+      }
+    }
+  }
+}
+
 export async function monitorIMessageProvider(opts: MonitorIMessageOpts = {}): Promise<void> {
   const runtime = resolveRuntime(opts);
   const cfg = opts.config ?? loadConfig();
@@ -126,6 +171,7 @@ export async function monitorIMessageProvider(opts: MonitorIMessageOpts = {}): P
       DEFAULT_GROUP_HISTORY_LIMIT,
   );
   const groupHistories = new Map<string, HistoryEntry[]>();
+  const sentMessageCache = new SentMessageCache();
   const textLimit = resolveTextChunkLimit(cfg, "imessage", accountInfo.accountId);
   const allowFrom = normalizeAllowList(opts.allowFrom ?? imessageCfg.allowFrom);
   const groupAllowFrom = normalizeAllowList(
@@ -347,6 +393,17 @@ export async function monitorIMessageProvider(opts: MonitorIMessageOpts = {}): P
     });
     const mentionRegexes = buildMentionRegexes(cfg, route.agentId);
     const messageText = (message.text ?? "").trim();
+
+    // Echo detection: check if the received message matches a recently sent message (within 5 seconds).
+    // Scope by conversation so same text in different chats is not conflated.
+    const echoScope = `${accountInfo.accountId}:${isGroup ? formatIMessageChatTarget(chatId) : `imessage:${sender}`}`;
+    if (messageText && sentMessageCache.has(echoScope, messageText)) {
+      logVerbose(
+        `imessage: skipping echo message (matches recently sent text within 5s): "${truncateUtf16Safe(messageText, 50)}"`,
+      );
+      return;
+    }
+
     const attachments = includeAttachments ? (message.attachments ?? []) : [];
     // Filter to valid attachments with paths
     const validAttachments = attachments.filter((entry) => entry?.original_path && !entry?.missing);
@@ -568,6 +625,7 @@ export async function monitorIMessageProvider(opts: MonitorIMessageOpts = {}): P
           runtime,
           maxBytes: mediaMaxBytes,
           textLimit,
+          sentMessageCache,
         });
       },
       onError: (err, info) => {