fix(imessage): normalize attributed echo prefixes

coder999999999 · coder999999999 · commit 9d69f0658835 · 2026-04-13T16:05:42.000-04:00
diff --git a/extensions/imessage/src/monitor/echo-cache.ts b/extensions/imessage/src/monitor/echo-cache.ts
@@ -23,11 +23,72 @@ export type SentMessageCache = {
 const SENT_MESSAGE_TEXT_TTL_MS = 4_000;
 const SENT_MESSAGE_ID_TTL_MS = 60_000;
 
+function isLowControlOrReplacementChar(char: string): boolean {
+  if (char === "\uFFFD") {
+    return true;
+  }
+  const code = char.charCodeAt(0);
+  return code <= 0x1f || (code >= 0x7f && code <= 0x9f);
+}
+
+function isHighAttributedLeadChar(char: string): boolean {
+  if (char === "\uFFFD") {
+    return true;
+  }
+  const code = char.charCodeAt(0);
+  return code >= 0x80 && code <= 0x9f;
+}
+
+function isAsciiPrintableChar(char: string): boolean {
+  const code = char.charCodeAt(0);
+  return code >= 0x20 && code <= 0x7e;
+}
+
+function stripLeadingIMessageAttributedTextPrefix(text: string): string {
+  let offset = 0;
+
+  while (offset < text.length) {
+    const first = text[offset];
+    if (!first) {
+      break;
+    }
+    const second = text[offset + 1];
+    const third = text[offset + 2];
+    if (
+      isHighAttributedLeadChar(first) &&
+      third &&
+      isLowControlOrReplacementChar(third) &&
+      (!second || isAsciiPrintableChar(second))
+    ) {
+      offset += second ? 3 : 2;
+      continue;
+    }
+
+    let runEnd = offset;
+    while (runEnd < text.length && runEnd - offset < 4) {
+      const char = text[runEnd];
+      if (!char || !isLowControlOrReplacementChar(char)) {
+        break;
+      }
+      runEnd += 1;
+    }
+    if (runEnd > offset) {
+      offset = runEnd;
+      continue;
+    }
+
+    break;
+  }
+
+  const stripped = offset > 0 ? text.slice(offset) : text;
+  return stripped || text;
+}
+
 function normalizeEchoTextKey(text: string | undefined): string | null {
   if (!text) {
     return null;
   }
-  const normalized = text.replace(/\r\n?/g, "\n").trim();
+  const normalized = stripLeadingIMessageAttributedTextPrefix(text).replace(/\r\n?/g, "\n").trim();
   return normalized ? normalized : null;
 }
 
diff --git a/extensions/imessage/src/monitor/monitor-provider.echo-cache.test.ts b/extensions/imessage/src/monitor/monitor-provider.echo-cache.test.ts
@@ -41,4 +41,23 @@ describe("iMessage sent-message echo cache", () => {
     expect(cache.has("acct:imessage:+1555", { text: "hello" })).toBe(false);
     expect(cache.has("acct:imessage:+1555", { messageId: "m-1" })).toBe(true);
   });
+
+  it("strips attributed-text prefix bytes before text fallback matching", () => {
+    vi.useFakeTimers();
+    vi.setSystemTime(new Date("2026-02-25T00:00:00Z"));
+    const cache = createSentMessageCache();
+
+    cache.remember("acct:imessage:+1555", {
+      text: "Confirmed full access",
+      messageId: "p:0/GUID-outbound",
+    });
+
+    expect(
+      cache.has(
+        "acct:imessage:+1555",
+        { text: "\u0093b\u0002Confirmed full access", messageId: "123799" },
+        true,
+      ),
+    ).toBe(true);
+  });
 });
diff --git a/extensions/imessage/src/monitor/self-chat-dedupe.test.ts b/extensions/imessage/src/monitor/self-chat-dedupe.test.ts
@@ -748,6 +748,41 @@ describe("self-chat is_from_me=true handling (Bruce Phase 2 fix)", () => {
     // With skipIdShortCircuit=false (default), ID mismatch causes early return false.
     expect(echoCache.has(scope, { text: "Cached reply", messageId: "123799" }, false)).toBe(false);
   });
+
+  it("drops self-chat echoes when reflected text carries attributed prefix bytes", () => {
+    vi.useFakeTimers();
+    vi.setSystemTime(new Date("2026-03-24T12:00:00Z"));
+
+    const echoCache = createSentMessageCache();
+    const selfChatCache = createSelfChatCache();
+    const scope = "default:imessage:+15551234567";
+    echoCache.remember(scope, {
+      text: "Cached reply",
+      messageId: "p:0/GUID-echo",
+    });
+
+    vi.advanceTimersByTime(1000);
+
+    const decision = resolveIMessageInboundDecision(
+      createParams({
+        message: {
+          id: 123799,
+          sender: "+15551234567",
+          chat_identifier: "+15551234567",
+          destination_caller_id: "+15551234567",
+          text: "\u0093b\u0002Cached reply",
+          is_from_me: true,
+          is_group: false,
+        },
+        messageText: "\u0093b\u0002Cached reply",
+        bodyText: "\u0093b\u0002Cached reply",
+        echoCache,
+        selfChatCache,
+      }),
+    );
+
+    expect(decision).toEqual({ kind: "drop", reason: "agent echo in self-chat" });
+  });
 });
 
 describe("echo cache — text fallback for null-id inbound messages", () => {
