diff --git a/hermes_cli/tools_config.py b/hermes_cli/tools_config.py
index 8e4bde883f..ba8849e6fa 100644
--- a/hermes_cli/tools_config.py
+++ b/hermes_cli/tools_config.py
@@ -546,6 +546,10 @@ def _get_platform_tools(
             ts_tools = set(resolve_toolset(ts_key))
             if ts_tools and ts_tools.issubset(all_tool_names):
                 enabled_toolsets.add(ts_key)
+        default_off = set(_DEFAULT_OFF_TOOLSETS)
+        if platform in default_off:
+            default_off.remove(platform)
+        enabled_toolsets -= default_off
 
     # Plugin toolsets: enabled by default unless explicitly disabled.
     # A plugin toolset is "known" for a platform once `hermes tools`
diff --git a/tests/hermes_cli/test_tools_config.py b/tests/hermes_cli/test_tools_config.py
index 8911d46dca..9fb2745acd 100644
--- a/tests/hermes_cli/test_tools_config.py
+++ b/tests/hermes_cli/test_tools_config.py
@@ -3,6 +3,8 @@
 from unittest.mock import patch
 
 from hermes_cli.tools_config import (
+    _DEFAULT_OFF_TOOLSETS,
+    _apply_toolset_change,
     _configure_provider,
     _get_platform_tools,
     _platform_toolset_summary,
@@ -21,6 +23,7 @@ def test_get_platform_tools_uses_default_when_platform_not_configured():
     enabled = _get_platform_tools(config, "cli")
 
     assert enabled
+    assert enabled.isdisjoint(_DEFAULT_OFF_TOOLSETS)
 
 
 def test_configurable_toolsets_include_messaging():
@@ -32,6 +35,12 @@ def test_get_platform_tools_default_telegram_includes_messaging():
     assert "messaging" in enabled
 
 
+def test_get_platform_tools_homeassistant_platform_keeps_homeassistant_toolset():
+    enabled = _get_platform_tools({}, "homeassistant")
+
+    assert "homeassistant" in enabled
+
+
 def test_get_platform_tools_preserves_explicit_empty_selection():
     config = {"platform_toolsets": {"cli": []}}
 
@@ -40,6 +49,32 @@ def test_get_platform_tools_preserves_explicit_empty_selection():
     assert enabled == set()
 
 
+def test_apply_toolset_change_from_default_does_not_enable_default_off_toolsets():
+    """Disabling one default toolset on a fresh config must not persist
+    default-off toolsets as explicitly enabled.
+    """
+    config = {}
+
+    with patch("hermes_cli.tools_config.save_config"):
+        _apply_toolset_change(config, "cli", ["memory"], "disable")
+
+    saved = set(config["platform_toolsets"]["cli"])
+    assert "memory" not in saved
+    assert "terminal" in saved
+    assert saved.isdisjoint(_DEFAULT_OFF_TOOLSETS)
+
+
+def test_apply_toolset_change_can_enable_default_off_toolset_from_default():
+    config = {}
+
+    with patch("hermes_cli.tools_config.save_config"):
+        _apply_toolset_change(config, "cli", ["homeassistant"], "enable")
+
+    saved = set(config["platform_toolsets"]["cli"])
+    assert "homeassistant" in saved
+    assert "terminal" in saved
+
+
 def test_get_platform_tools_handles_null_platform_toolsets():
     """YAML `platform_toolsets:` with no value parses as None — the old
     ``config.get("platform_toolsets", {})`` pattern would then crash with