diff --git a/cli.py b/cli.py
index 937966b05..3ecde4263 100755
--- a/cli.py
+++ b/cli.py
@@ -1877,6 +1877,19 @@ class HermesCLI:
             print("    /personality    - Use a predefined personality")
             print()
     
+
+    @staticmethod
+    def _resolve_personality_prompt(value) -> str:
+        """Accept string or dict personality value; return system prompt string."""
+        if isinstance(value, dict):
+            parts = [value.get("system_prompt", "")]
+            if value.get("tone"):
+                parts.append(f'Tone: {value["tone"]}' )
+            if value.get("style"):
+                parts.append(f'Style: {value["style"]}' )
+            return "\n".join(p for p in parts if p)
+        return str(value)
+
     def _handle_personality_command(self, cmd: str):
         """Handle the /personality command to set predefined personalities."""
         parts = cmd.split(maxsplit=1)
@@ -1885,8 +1898,16 @@ class HermesCLI:
             # Set personality
             personality_name = parts[1].strip().lower()
             
-            if personality_name in self.personalities:
-                self.system_prompt = self.personalities[personality_name]
+            if personality_name in ("none", "default", "neutral"):
+                self.system_prompt = ""
+                self.agent = None  # Force re-init
+                if save_config_value("agent.system_prompt", ""):
+                    print("(^_^)b Personality cleared (saved to config)")
+                else:
+                    print("(^_^) Personality cleared (session only)")
+                print("  No personality overlay — using base agent behavior.")
+            elif personality_name in self.personalities:
+                self.system_prompt = self._resolve_personality_prompt(self.personalities[personality_name])
                 self.agent = None  # Force re-init
                 if save_config_value("agent.system_prompt", self.system_prompt):
                     print(f"(^_^)b Personality set to '{personality_name}' (saved to config)")
@@ -1895,7 +1916,7 @@ class HermesCLI:
                 print(f"  \"{self.system_prompt[:60]}{'...' if len(self.system_prompt) > 60 else ''}\"")
             else:
                 print(f"(._.) Unknown personality: {personality_name}")
-                print(f"  Available: {', '.join(self.personalities.keys())}")
+                print(f"  Available: none, {', '.join(self.personalities.keys())}")
         else:
             # Show available personalities
             print()
@@ -1903,8 +1924,13 @@ class HermesCLI:
             print("|" + " " * 12 + "(^o^)/ Personalities" + " " * 15 + "|")
             print("+" + "-" * 50 + "+")
             print()
+            print(f"  {'none':<12} - (no personality overlay)")
             for name, prompt in self.personalities.items():
-                print(f"  {name:<12} - \"{prompt}\"")
+                if isinstance(prompt, dict):
+                    preview = prompt.get("description") or prompt.get("system_prompt", "")[:50]
+                else:
+                    preview = str(prompt)[:50]
+                print(f"  {name:<12} - {preview}")
             print()
             print("  Usage: /personality <name>")
             print()
diff --git a/gateway/run.py b/gateway/run.py
index b32f2d2d0..8fbd8d28b 100644
--- a/gateway/run.py
+++ b/gateway/run.py
@@ -1536,14 +1536,39 @@ class GatewayRunner:
 
         if not args:
             lines = ["🎭 **Available Personalities**\n"]
+            lines.append("• `none` — (no personality overlay)")
             for name, prompt in personalities.items():
-                preview = prompt[:50] + "..." if len(prompt) > 50 else prompt
+                if isinstance(prompt, dict):
+                    preview = prompt.get("description") or prompt.get("system_prompt", "")[:50]
+                else:
+                    preview = prompt[:50] + "..." if len(prompt) > 50 else prompt
                 lines.append(f"• `{name}` — {preview}")
             lines.append(f"\nUsage: `/personality <name>`")
             return "\n".join(lines)
 
-        if args in personalities:
-            new_prompt = personalities[args]
+        def _resolve_prompt(value):
+            if isinstance(value, dict):
+                parts = [value.get("system_prompt", "")]
+                if value.get("tone"):
+                    parts.append(f'Tone: {value["tone"]}')
+                if value.get("style"):
+                    parts.append(f'Style: {value["style"]}')
+                return "\n".join(p for p in parts if p)
+            return str(value)
+
+        if args in ("none", "default", "neutral"):
+            try:
+                if "agent" not in config or not isinstance(config.get("agent"), dict):
+                    config["agent"] = {}
+                config["agent"]["system_prompt"] = ""
+                with open(config_path, "w") as f:
+                    yaml.dump(config, f, default_flow_style=False, sort_keys=False)
+            except Exception as e:
+                return f"⚠️ Failed to save personality change: {e}"
+            self._ephemeral_system_prompt = ""
+            return "🎭 Personality cleared — using base agent behavior.\n_(takes effect on next message)_"
+        elif args in personalities:
+            new_prompt = _resolve_prompt(personalities[args])
 
             # Write to config.yaml, same pattern as CLI save_config_value.
             try:
@@ -1560,7 +1585,7 @@ class GatewayRunner:
 
             return f"🎭 Personality set to **{args}**\n_(takes effect on next message)_"
 
-        available = ", ".join(f"`{n}`" for n in personalities.keys())
+        available = "`none`, " + ", ".join(f"`{n}`" for n in personalities.keys())
         return f"Unknown personality: `{args}`\n\nAvailable: {available}"
     
     async def _handle_retry_command(self, event: MessageEvent) -> str:
diff --git a/hermes_cli/config.py b/hermes_cli/config.py
index 0e6f51c1a..1695f2b0a 100644
--- a/hermes_cli/config.py
+++ b/hermes_cli/config.py
@@ -147,6 +147,10 @@ DEFAULT_CONFIG = {
 
     # Permanently allowed dangerous command patterns (added via "always" approval)
     "command_allowlist": [],
+    # Custom personalities — add your own entries here
+    # Supports string format: {"name": "system prompt"}
+    # Or dict format: {"name": {"description": "...", "system_prompt": "...", "tone": "...", "style": "..."}}
+    "personalities": {},
 
     # Config schema version - bump this when adding new required fields
     "_config_version": 5,
diff --git a/tests/test_personality_none.py b/tests/test_personality_none.py
new file mode 100644
index 000000000..ec27838fe
--- /dev/null
+++ b/tests/test_personality_none.py
@@ -0,0 +1,212 @@
+"""Tests for /personality none — clearing personality overlay."""
+import pytest
+from unittest.mock import MagicMock, patch, mock_open
+import yaml
+
+
+# ── CLI tests ──────────────────────────────────────────────────────────────
+
+class TestCLIPersonalityNone:
+
+    def _make_cli(self, personalities=None):
+        from cli import HermesCLI
+        cli = HermesCLI.__new__(HermesCLI)
+        cli.personalities = personalities or {
+            "helpful": "You are helpful.",
+            "concise": "You are concise.",
+        }
+        cli.system_prompt = "You are kawaii~"
+        cli.agent = MagicMock()
+        cli.console = MagicMock()
+        return cli
+
+    def test_none_clears_system_prompt(self):
+        cli = self._make_cli()
+        with patch("cli.save_config_value", return_value=True):
+            cli._handle_personality_command("/personality none")
+        assert cli.system_prompt == ""
+
+    def test_default_clears_system_prompt(self):
+        cli = self._make_cli()
+        with patch("cli.save_config_value", return_value=True):
+            cli._handle_personality_command("/personality default")
+        assert cli.system_prompt == ""
+
+    def test_neutral_clears_system_prompt(self):
+        cli = self._make_cli()
+        with patch("cli.save_config_value", return_value=True):
+            cli._handle_personality_command("/personality neutral")
+        assert cli.system_prompt == ""
+
+    def test_none_forces_agent_reinit(self):
+        cli = self._make_cli()
+        with patch("cli.save_config_value", return_value=True):
+            cli._handle_personality_command("/personality none")
+        assert cli.agent is None
+
+    def test_none_saves_to_config(self):
+        cli = self._make_cli()
+        with patch("cli.save_config_value", return_value=True) as mock_save:
+            cli._handle_personality_command("/personality none")
+        mock_save.assert_called_once_with("agent.system_prompt", "")
+
+    def test_known_personality_still_works(self):
+        cli = self._make_cli()
+        with patch("cli.save_config_value", return_value=True):
+            cli._handle_personality_command("/personality helpful")
+        assert cli.system_prompt == "You are helpful."
+
+    def test_unknown_personality_shows_none_in_available(self, capsys):
+        cli = self._make_cli()
+        cli._handle_personality_command("/personality nonexistent")
+        output = capsys.readouterr().out
+        assert "none" in output.lower()
+
+    def test_list_shows_none_option(self):
+        cli = self._make_cli()
+        with patch("builtins.print") as mock_print:
+            cli._handle_personality_command("/personality")
+        output = " ".join(str(c) for c in mock_print.call_args_list)
+        assert "none" in output.lower()
+
+
+# ── Gateway tests ──────────────────────────────────────────────────────────
+
+class TestGatewayPersonalityNone:
+
+    def _make_event(self, args=""):
+        event = MagicMock()
+        event.get_command.return_value = "personality"
+        event.get_command_args.return_value = args
+        return event
+
+    def _make_runner(self, personalities=None):
+        from gateway.run import GatewayRunner
+        runner = GatewayRunner.__new__(GatewayRunner)
+        runner._ephemeral_system_prompt = "You are kawaii~"
+        runner.config = {
+            "agent": {
+                "personalities": personalities or {"helpful": "You are helpful."}
+            }
+        }
+        return runner
+
+    @pytest.mark.asyncio
+    async def test_none_clears_ephemeral_prompt(self, tmp_path):
+        runner = self._make_runner()
+        config_data = {"agent": {"personalities": {"helpful": "You are helpful."}, "system_prompt": "kawaii"}}
+        config_file = tmp_path / "config.yaml"
+        config_file.write_text(yaml.dump(config_data))
+
+        with patch("gateway.run._hermes_home", tmp_path):
+            event = self._make_event("none")
+            result = await runner._handle_personality_command(event)
+
+        assert runner._ephemeral_system_prompt == ""
+        assert "cleared" in result.lower()
+
+    @pytest.mark.asyncio
+    async def test_default_clears_ephemeral_prompt(self, tmp_path):
+        runner = self._make_runner()
+        config_data = {"agent": {"personalities": {"helpful": "You are helpful."}}}
+        config_file = tmp_path / "config.yaml"
+        config_file.write_text(yaml.dump(config_data))
+
+        with patch("gateway.run._hermes_home", tmp_path):
+            event = self._make_event("default")
+            result = await runner._handle_personality_command(event)
+
+        assert runner._ephemeral_system_prompt == ""
+
+    @pytest.mark.asyncio
+    async def test_list_includes_none(self, tmp_path):
+        runner = self._make_runner()
+        config_data = {"agent": {"personalities": {"helpful": "You are helpful."}}}
+        config_file = tmp_path / "config.yaml"
+        config_file.write_text(yaml.dump(config_data))
+
+        with patch("gateway.run._hermes_home", tmp_path):
+            event = self._make_event("")
+            result = await runner._handle_personality_command(event)
+
+        assert "none" in result.lower()
+
+    @pytest.mark.asyncio
+    async def test_unknown_shows_none_in_available(self, tmp_path):
+        runner = self._make_runner()
+        config_data = {"agent": {"personalities": {"helpful": "You are helpful."}}}
+        config_file = tmp_path / "config.yaml"
+        config_file.write_text(yaml.dump(config_data))
+
+        with patch("gateway.run._hermes_home", tmp_path):
+            event = self._make_event("nonexistent")
+            result = await runner._handle_personality_command(event)
+
+        assert "none" in result.lower()
+
+
+class TestPersonalityDictFormat:
+    """Test dict-format custom personalities with description, tone, style."""
+
+    def _make_cli(self, personalities):
+        from cli import HermesCLI
+        cli = HermesCLI.__new__(HermesCLI)
+        cli.personalities = personalities
+        cli.system_prompt = ""
+        cli.agent = None
+        cli.console = MagicMock()
+        return cli
+
+    def test_dict_personality_uses_system_prompt(self):
+        cli = self._make_cli({
+            "coder": {
+                "description": "Expert programmer",
+                "system_prompt": "You are an expert programmer.",
+                "tone": "technical",
+                "style": "concise",
+            }
+        })
+        with patch("cli.save_config_value", return_value=True):
+            cli._handle_personality_command("/personality coder")
+        assert "You are an expert programmer." in cli.system_prompt
+
+    def test_dict_personality_includes_tone(self):
+        cli = self._make_cli({
+            "coder": {
+                "system_prompt": "You are an expert programmer.",
+                "tone": "technical and precise",
+            }
+        })
+        with patch("cli.save_config_value", return_value=True):
+            cli._handle_personality_command("/personality coder")
+        assert "Tone: technical and precise" in cli.system_prompt
+
+    def test_dict_personality_includes_style(self):
+        cli = self._make_cli({
+            "coder": {
+                "system_prompt": "You are an expert programmer.",
+                "style": "use code examples",
+            }
+        })
+        with patch("cli.save_config_value", return_value=True):
+            cli._handle_personality_command("/personality coder")
+        assert "Style: use code examples" in cli.system_prompt
+
+    def test_string_personality_still_works(self):
+        cli = self._make_cli({"helper": "You are helpful."})
+        with patch("cli.save_config_value", return_value=True):
+            cli._handle_personality_command("/personality helper")
+        assert cli.system_prompt == "You are helpful."
+
+    def test_resolve_prompt_dict_no_tone_no_style(self):
+        from cli import HermesCLI
+        result = HermesCLI._resolve_personality_prompt({
+            "description": "A helper",
+            "system_prompt": "You are helpful.",
+        })
+        assert result == "You are helpful."
+
+    def test_resolve_prompt_string(self):
+        from cli import HermesCLI
+        result = HermesCLI._resolve_personality_prompt("You are helpful.")
+        assert result == "You are helpful."