diff --git a/gateway/platforms/discord.py b/gateway/platforms/discord.py
index 257756ad..e68e5292 100644
--- a/gateway/platforms/discord.py
+++ b/gateway/platforms/discord.py
@@ -43,6 +43,23 @@ from gateway.platforms.base import (
 )
 
 
+def _clean_discord_id(entry: str) -> str:
+    """Strip common prefixes from a Discord user ID or username entry.
+
+    Users sometimes paste IDs with prefixes like ``user:123``, ``<@123>``,
+    or ``<@!123>`` from Discord's UI or other tools.  This normalises the
+    entry to just the bare ID or username.
+    """
+    entry = entry.strip()
+    # Strip Discord mention syntax: <@123> or <@!123>
+    if entry.startswith("<@") and entry.endswith(">"):
+        entry = entry.lstrip("<@!").rstrip(">")
+    # Strip "user:" prefix (seen in some Discord tools / onboarding pastes)
+    if entry.lower().startswith("user:"):
+        entry = entry[5:]
+    return entry.strip()
+
+
 def check_discord_requirements() -> bool:
     """Check if Discord dependencies are available."""
     return DISCORD_AVAILABLE
@@ -99,7 +116,8 @@ class DiscordAdapter(BasePlatformAdapter):
             allowed_env = os.getenv("DISCORD_ALLOWED_USERS", "")
             if allowed_env:
                 self._allowed_user_ids = {
-                    uid.strip() for uid in allowed_env.split(",") if uid.strip()
+                    _clean_discord_id(uid) for uid in allowed_env.split(",")
+                    if uid.strip()
                 }
             
             adapter_self = self  # capture for closure
diff --git a/hermes_cli/gateway.py b/hermes_cli/gateway.py
index 26a8f598..5ba2f64b 100644
--- a/hermes_cli/gateway.py
+++ b/hermes_cli/gateway.py
@@ -623,6 +623,18 @@ def _setup_standard_platform(platform: dict):
             value = prompt(f"  {var['prompt']}", password=False)
             if value:
                 cleaned = value.replace(" ", "")
+                # For Discord, strip common prefixes (user:123, <@123>, <@!123>)
+                if "DISCORD" in var["name"]:
+                    parts = []
+                    for uid in cleaned.split(","):
+                        uid = uid.strip()
+                        if uid.startswith("<@") and uid.endswith(">"):
+                            uid = uid.lstrip("<@!").rstrip(">")
+                        if uid.lower().startswith("user:"):
+                            uid = uid[5:]
+                        if uid:
+                            parts.append(uid)
+                    cleaned = ",".join(parts)
                 save_env_value(var["name"], cleaned)
                 print_success(f"  Saved — only these users can interact with the bot.")
                 allowed_val_set = cleaned
diff --git a/hermes_cli/setup.py b/hermes_cli/setup.py
index baff9e6e..b2e53c87 100644
--- a/hermes_cli/setup.py
+++ b/hermes_cli/setup.py
@@ -1935,7 +1935,17 @@ def setup_gateway(config: dict):
                 "Allowed user IDs or usernames (comma-separated, leave empty for open access)"
             )
             if allowed_users:
-                save_env_value("DISCORD_ALLOWED_USERS", allowed_users.replace(" ", ""))
+                # Clean up common prefixes (user:123, <@123>, <@!123>)
+                cleaned_ids = []
+                for uid in allowed_users.replace(" ", "").split(","):
+                    uid = uid.strip()
+                    if uid.startswith("<@") and uid.endswith(">"):
+                        uid = uid.lstrip("<@!").rstrip(">")
+                    if uid.lower().startswith("user:"):
+                        uid = uid[5:]
+                    if uid:
+                        cleaned_ids.append(uid)
+                save_env_value("DISCORD_ALLOWED_USERS", ",".join(cleaned_ids))
                 print_success("Discord allowlist configured")
             else:
                 print_info(
@@ -1970,8 +1980,18 @@ def setup_gateway(config: dict):
                 )
                 allowed_users = prompt("Allowed user IDs (comma-separated)")
                 if allowed_users:
+                    # Clean up common prefixes (user:123, <@123>, <@!123>)
+                    cleaned_ids = []
+                    for uid in allowed_users.replace(" ", "").split(","):
+                        uid = uid.strip()
+                        if uid.startswith("<@") and uid.endswith(">"):
+                            uid = uid.lstrip("<@!").rstrip(">")
+                        if uid.lower().startswith("user:"):
+                            uid = uid[5:]
+                        if uid:
+                            cleaned_ids.append(uid)
                     save_env_value(
-                        "DISCORD_ALLOWED_USERS", allowed_users.replace(" ", "")
+                        "DISCORD_ALLOWED_USERS", ",".join(cleaned_ids)
                     )
                     print_success("Discord allowlist configured")