@@ -1330,12 +1330,14 @@ def _validate_install_conflicts(self, manifest: ExtensionManifest) -> None:
 
         from .._init_options import MISSING_INIT_OPTIONS_FILE, resolve_active_agent_for_registration
         from ..integrations import INTEGRATION_REGISTRY
+        from ..integrations.installer import project_integrations
 
         active_agent = resolve_active_agent_for_registration(self.project_root)
-        agents = INTEGRATION_REGISTRY if active_agent is MISSING_INIT_OPTIONS_FILE else [active_agent]
-        for agent in agents:
-            if agent:
-                self._validate_command_destinations(manifest, agent)
+        with project_integrations(self.project_root):
+            agents = list(INTEGRATION_REGISTRY) if active_agent is MISSING_INIT_OPTIONS_FILE else [active_agent]
+            for agent in agents:
+                if agent:
+                    self._validate_command_destinations(manifest, agent)
 
     @project_registration
     def _validate_command_destinations(self, manifest: ExtensionManifest, agent_name: str) -> None:
 
@@ -527,6 +527,19 @@ def test_external_adapter_removal_preserves_unowned_command(self, tmp_path, offl
         assert result.exit_code == 0, result.output
         assert command.read_bytes() == b"USER OWNED FILE\n"
 
+    def test_extension_add_without_init_options_loads_installed_adapters(self, tmp_path, offline_adapter):
+        from specify_cli.integrations.installer import unload_installed_integrations
+
+        project = _init_project(tmp_path, "claude")
+        (project / ".specify/init-options.json").unlink()
+        result = offline_adapter(project)
+        assert result.exit_code == 0, result.output
+        unload_installed_integrations()
+
+        source = _write_command_extension(tmp_path)
+        result = _run_in_project(project, ["extension", "add", "--dev", str(source)])
+        assert result.exit_code == 0, result.output
+
     @pytest.mark.parametrize("empty_manifest", [False, True])
     def test_upgrade_refuses_kiro_prompt_rename_while_presets_are_installed(
         self, tmp_path, monkeypatch, empty_manifest