fix(email): ignore self-sent mailbox messages

Skip inbound emails that come from the bot's own configured addresses so a mailbox wired to the same SMTP/IMAP account does not trigger infinite reply loops.

nanobot/channels/email.py

@@ -118,6 +118,7 @@ class EmailChannel(BaseChannel):
             config = EmailConfig.model_validate(config)
         super().__init__(config, bus)
         self.config: EmailConfig = config
+        self._self_addresses = self._collect_self_addresses()
         self._last_subject_by_chat: dict[str, str] = {}
         self._last_message_id_by_chat: dict[str, str] = {}
         self._processed_uids: set[str] = set()  # Capped to prevent unbounded growth
@@ -379,6 +380,12 @@ class EmailChannel(BaseChannel):
                 sender = parseaddr(parsed.get("From", ""))[1].strip().lower()
                 if not sender:
                     continue
+                if self._is_self_address(sender):
+                    logger.info("Email from {} ignored: matches bot-owned address", sender)
+                    self._remember_processed_uid(uid, dedupe, cycle_uids)
+                    if mark_seen:
+                        client.store(imap_id, "+FLAGS", "\\Seen")
+                    continue
 
                 # --- Anti-spoofing: verify Authentication-Results ---
                 spf_pass, dkim_pass = self._check_authentication_results(parsed)
@@ -446,14 +453,7 @@ class EmailChannel(BaseChannel):
                     }
                 )
 
-                if uid:
-                    cycle_uids.add(uid)
-                if dedupe and uid:
-                    self._processed_uids.add(uid)
-                    # mark_seen is the primary dedup; this set is a safety net
-                    if len(self._processed_uids) > self._MAX_PROCESSED_UIDS:
-                        # Evict a random half to cap memory; mark_seen is the primary dedup
-                        self._processed_uids = set(list(self._processed_uids)[len(self._processed_uids) // 2:])
+                self._remember_processed_uid(uid, dedupe, cycle_uids)
 
                 if mark_seen:
                     client.store(imap_id, "+FLAGS", "\\Seen")
@@ -463,6 +463,50 @@ class EmailChannel(BaseChannel):
             except Exception:
                 pass
 
+    def _collect_self_addresses(self) -> set[str]:
+        """Return normalized email addresses owned by this channel instance."""
+        candidates = (
+            self.config.from_address,
+            self.config.smtp_username,
+            self.config.imap_username,
+        )
+        normalized = {
+            addr
+            for candidate in candidates
+            if (addr := self._normalize_address(candidate))
+        }
+        return normalized
+
+    @staticmethod
+    def _normalize_address(value: str) -> str:
+        """Normalize an address or mailbox-like identifier for comparisons."""
+        raw = (value or "").strip()
+        if not raw:
+            return ""
+        parsed = parseaddr(raw)[1].strip().lower()
+        if parsed:
+            return parsed
+        if "@" in raw:
+            return raw.lower()
+        return ""
+
+    def _is_self_address(self, sender: str) -> bool:
+        """Return True when an inbound sender belongs to the bot itself."""
+        normalized_sender = self._normalize_address(sender)
+        return bool(normalized_sender) and normalized_sender in self._self_addresses
+
+    def _remember_processed_uid(self, uid: str, dedupe: bool, cycle_uids: set[str]) -> None:
+        """Track a fetched UID so skipped messages are not reprocessed forever."""
+        if not uid:
+            return
+        cycle_uids.add(uid)
+        if dedupe:
+            self._processed_uids.add(uid)
+            # mark_seen is the primary dedup; this set is a safety net
+            if len(self._processed_uids) > self._MAX_PROCESSED_UIDS:
+                # Evict a random half to cap memory; mark_seen is the primary dedup
+                self._processed_uids = set(list(self._processed_uids)[len(self._processed_uids) // 2:])
+
     @classmethod
     def _is_stale_imap_error(cls, exc: Exception) -> bool:
         message = str(exc).lower()

tests/channels/test_email_channel.py

@@ -92,6 +92,46 @@ def test_fetch_new_messages_parses_unseen_and_marks_seen(monkeypatch) -> None:
     assert items_again == []
 
 
+def test_fetch_new_messages_skips_self_sent_email_and_marks_seen(monkeypatch) -> None:
+    raw = _make_raw_email(from_addr="Nanobot <bot@example.com>", subject="Loop test")
+
+    class FakeIMAP:
+        def __init__(self) -> None:
+            self.store_calls: list[tuple[bytes, str, str]] = []
+
+        def login(self, _user: str, _pw: str):
+            return "OK", [b"logged in"]
+
+        def select(self, _mailbox: str):
+            return "OK", [b"1"]
+
+        def search(self, *_args):
+            return "OK", [b"1"]
+
+        def fetch(self, _imap_id: bytes, _parts: str):
+            return "OK", [(b"1 (UID 123 BODY[] {200})", raw), b")"]
+
+        def store(self, imap_id: bytes, op: str, flags: str):
+            self.store_calls.append((imap_id, op, flags))
+            return "OK", [b""]
+
+        def logout(self):
+            return "BYE", [b""]
+
+    fake = FakeIMAP()
+    monkeypatch.setattr("nanobot.channels.email.imaplib.IMAP4_SSL", lambda _h, _p: fake)
+
+    channel = EmailChannel(_make_config(from_address="bot@example.com"), MessageBus())
+    items = channel._fetch_new_messages()
+
+    assert items == []
+    assert fake.store_calls == [(b"1", "+FLAGS", "\\Seen")]
+
+    # Same UID should still be deduped after being ignored.
+    items_again = channel._fetch_new_messages()
+    assert items_again == []
+
+
 def test_fetch_new_messages_retries_once_when_imap_connection_goes_stale(monkeypatch) -> None:
     raw = _make_raw_email(subject="Invoice", body="Please pay")
     fail_once = {"pending": True}