diff --git a/plugins/platforms/simplex/adapter.py b/plugins/platforms/simplex/adapter.py
index 8dd65f3d53..3a1b458271 100644
--- a/plugins/platforms/simplex/adapter.py
+++ b/plugins/platforms/simplex/adapter.py
@@ -146,6 +146,10 @@ class SimplexAdapter(BasePlatformAdapter):
         self._health_task = asyncio.create_task(self._health_monitor())
         self._mark_connected()
         logger.info("SimpleX: connected to %s", self.ws_url)
+        names = [u for u in os.getenv("SIMPLEX_ALLOWED_USERS", "").split(",") if u.strip() not in ("", "*") and not u.strip().isdigit()]
+        if names and not is_reconnect:
+            logger.warning("SimpleX: SIMPLEX_ALLOWED_USERS entries %s are not numeric contactIds and are ignored "
+                           "(display names are not trusted; see /contacts for IDs)", names)
         self._wire_plugin_handlers(None)
         return True
 
diff --git a/website/docs/user-guide/messaging/simplex.md b/website/docs/user-guide/messaging/simplex.md
index 83fb176a41..e1317f66b3 100644
--- a/website/docs/user-guide/messaging/simplex.md
+++ b/website/docs/user-guide/messaging/simplex.md
@@ -52,7 +52,7 @@ SIMPLEX_HOME_CHANNEL=<contact-id>
 | Variable | Required | Description |
 |---|---|---|
 | `SIMPLEX_WS_URL` | Yes | WebSocket URL of the simplex-chat daemon |
-| `SIMPLEX_ALLOWED_USERS` | Recommended | Comma-separated allowlist. Each entry can be a numeric `contactId` **or** a display name — both forms work. |
+| `SIMPLEX_ALLOWED_USERS` | Recommended | Comma-separated allowlist of numeric `contactId`s. Display names are **not** accepted — any contact can change theirs. |
 | `SIMPLEX_ALLOW_ALL_USERS` | Optional | Set `true` to allow every contact (use carefully) |
 | `SIMPLEX_AUTO_ACCEPT` | Optional | Auto-accept incoming contact requests (default: `true`) |
 | `SIMPLEX_GROUP_ALLOWED` | Optional | Comma-separated group IDs the bot participates in, or `*` for any group. Omit to ignore group messages entirely |
@@ -60,15 +60,15 @@ SIMPLEX_HOME_CHANNEL=<contact-id>
 | `SIMPLEX_HOME_CHANNEL_NAME` | Optional | Human label for the home channel |
 | `HERMES_SIMPLEX_TEXT_BATCH_DELAY` | Optional | Quiet-period seconds (default: `0.8`) used to concatenate rapid-fire inbound text messages into one event |
 
-## Find your contact ID or display name
+## Find your contact ID
 
-After starting the daemon, open a conversation with your agent contact. The numeric `contactId` appears in session logs. If you'd rather use the display name shown in the SimpleX UI, that works too — `SIMPLEX_ALLOWED_USERS` accepts either form.
+After starting the daemon, open a conversation with your agent contact. The numeric `contactId` appears in session logs (or run `/contacts` in the daemon). `SIMPLEX_ALLOWED_USERS` matches only this ID: display names are chosen by the contact and can collide, so they are ignored.
 
 ## Authorization
 
 By default **all contacts are denied**. You must either:
 
-1. Set `SIMPLEX_ALLOWED_USERS` to a comma-separated list of `contactId`s and/or display names (e.g. `SIMPLEX_ALLOWED_USERS=4,alice` matches either contactId 4 or the contact whose display name is "alice"), or
+1. Set `SIMPLEX_ALLOWED_USERS` to a comma-separated list of numeric `contactId`s (e.g. `SIMPLEX_ALLOWED_USERS=4,9`), or
 2. Use **DM pairing** — send any message to the bot and it will reply with a pairing code. Enter that code via `hermes pairing approve simplex <CODE>`.
 
 ## Group chats