diff --git a/hermes_cli/plugins.py b/hermes_cli/plugins.py
index 11f18f071..3dd7af823 100644
--- a/hermes_cli/plugins.py
+++ b/hermes_cli/plugins.py
@@ -734,6 +734,30 @@ class PluginManager:
                 )
                 kind = "standalone"
 
+            # Auto-coerce user-installed memory providers to kind="exclusive"
+            # so they're routed to plugins/memory discovery instead of being
+            # loaded by the general PluginManager (which has no
+            # register_memory_provider on PluginContext). Mirrors the
+            # heuristic in plugins/memory/__init__.py:_is_memory_provider_dir.
+            # Bundled memory providers are already skipped via skip_names.
+            if kind == "standalone" and "kind" not in data:
+                init_file = plugin_dir / "__init__.py"
+                if init_file.exists():
+                    try:
+                        source_text = init_file.read_text(errors="replace")[:8192]
+                        if (
+                            "register_memory_provider" in source_text
+                            or "MemoryProvider" in source_text
+                        ):
+                            kind = "exclusive"
+                            logger.debug(
+                                "Plugin %s: detected memory provider, "
+                                "treating as kind='exclusive'",
+                                key,
+                            )
+                    except Exception:
+                        pass
+
             return PluginManifest(
                 name=name,
                 version=str(data.get("version", "")),
diff --git a/run_agent.py b/run_agent.py
index ef4019163..ec5e86d78 100644
--- a/run_agent.py
+++ b/run_agent.py
@@ -10044,6 +10044,27 @@ class AIAgent:
                         if self._try_refresh_nous_client_credentials(force=True):
                             print(f"{self.log_prefix}🔐 Nous agent key refreshed after 401. Retrying request...")
                             continue
+                        # Credential refresh didn't help — show diagnostic info.
+                        # Most common causes: Portal OAuth expired/revoked,
+                        # account out of credits, or agent key blocked.
+                        from hermes_constants import display_hermes_home as _dhh_fn
+                        _dhh = _dhh_fn()
+                        _body_text = ""
+                        try:
+                            _body = getattr(api_error, "body", None) or getattr(api_error, "response", None)
+                            if _body is not None:
+                                _body_text = str(_body)[:200]
+                        except Exception:
+                            pass
+                        print(f"{self.log_prefix}🔐 Nous 401 — Portal authentication failed.")
+                        if _body_text:
+                            print(f"{self.log_prefix}   Response: {_body_text}")
+                        print(f"{self.log_prefix}   Most likely: Portal OAuth expired, account out of credits, or agent key revoked.")
+                        print(f"{self.log_prefix}   Troubleshooting:")
+                        print(f"{self.log_prefix}     • Re-authenticate: hermes login --provider nous")
+                        print(f"{self.log_prefix}     • Check credits / billing: https://portal.nousresearch.com")
+                        print(f"{self.log_prefix}     • Verify stored credentials: {_dhh}/auth.json")
+                        print(f"{self.log_prefix}     • Switch providers temporarily: /model <model> --provider openrouter")
                     if (
                         self.api_mode == "anthropic_messages"
                         and status_code == 401
diff --git a/tests/hermes_cli/test_plugins.py b/tests/hermes_cli/test_plugins.py
index 9433ecdca..04d056771 100644
--- a/tests/hermes_cli/test_plugins.py
+++ b/tests/hermes_cli/test_plugins.py
@@ -250,6 +250,73 @@ class TestPluginLoading:
 
         assert "hermes_plugins.ns_plugin" in sys.modules
 
+    def test_user_memory_plugin_auto_coerced_to_exclusive(self, tmp_path, monkeypatch):
+        """User-installed memory plugins must NOT be loaded by the general
+        PluginManager — they belong to plugins/memory discovery.
+
+        Regression test for the mempalace crash:
+            'PluginContext' object has no attribute 'register_memory_provider'
+
+        A plugin that calls ``ctx.register_memory_provider`` in its
+        ``__init__.py`` should be auto-detected and treated as
+        ``kind: exclusive`` so the general loader records the manifest but
+        does not import/register() it. The real activation happens through
+        ``plugins/memory/__init__.py`` via ``memory.provider`` config.
+        """
+        plugins_dir = tmp_path / "hermes_test" / "plugins"
+        plugin_dir = plugins_dir / "mempalace"
+        plugin_dir.mkdir(parents=True)
+        # No explicit `kind:` — the heuristic should kick in.
+        (plugin_dir / "plugin.yaml").write_text(yaml.dump({"name": "mempalace"}))
+        (plugin_dir / "__init__.py").write_text(
+            "class MemPalaceProvider:\n"
+            "    pass\n"
+            "def register(ctx):\n"
+            "    ctx.register_memory_provider('mempalace', MemPalaceProvider)\n"
+        )
+        # Even if the user explicitly enables it in config, the loader
+        # should still treat it as exclusive and skip general loading.
+        hermes_home = tmp_path / "hermes_test"
+        (hermes_home / "config.yaml").write_text(
+            yaml.safe_dump({"plugins": {"enabled": ["mempalace"]}})
+        )
+        monkeypatch.setenv("HERMES_HOME", str(hermes_home))
+
+        mgr = PluginManager()
+        mgr.discover_and_load()
+
+        assert "mempalace" in mgr._plugins
+        entry = mgr._plugins["mempalace"]
+        assert entry.manifest.kind == "exclusive", (
+            f"Expected auto-coerced kind='exclusive', got {entry.manifest.kind}"
+        )
+        # Not loaded by general manager (no register() call, no AttributeError).
+        assert not entry.enabled
+        assert entry.module is None
+        assert "exclusive" in (entry.error or "").lower()
+
+    def test_explicit_standalone_kind_not_coerced(self, tmp_path, monkeypatch):
+        """If a plugin explicitly declares ``kind: standalone`` in its
+        manifest, the memory-provider heuristic must NOT override it —
+        even if the source happens to mention ``MemoryProvider``.
+        """
+        plugins_dir = tmp_path / "hermes_test" / "plugins"
+        plugin_dir = plugins_dir / "not_memory"
+        plugin_dir.mkdir(parents=True)
+        (plugin_dir / "plugin.yaml").write_text(
+            yaml.dump({"name": "not_memory", "kind": "standalone"})
+        )
+        (plugin_dir / "__init__.py").write_text(
+            "# This plugin inspects MemoryProvider docs but isn't one.\n"
+            "def register(ctx):\n    pass\n"
+        )
+        monkeypatch.setenv("HERMES_HOME", str(tmp_path / "hermes_test"))
+
+        mgr = PluginManager()
+        mgr.discover_and_load()
+
+        assert mgr._plugins["not_memory"].manifest.kind == "standalone"
+
 
 # ── TestPluginHooks ────────────────────────────────────────────────────────