diff --git a/crates/application/src/plugin/mod.rs b/crates/application/src/plugin/mod.rs
index 3b1c153..0a5d314 100644
--- a/crates/application/src/plugin/mod.rs
+++ b/crates/application/src/plugin/mod.rs
@@ -507,7 +507,7 @@ async fn install_from_staged(
         .await
         .map_err(map_store)?;
     let mut registry = registry_store.load_registry().await.map_err(map_registry)?;
-    let entry = PluginRegistryEntry {
+    let mut entry = PluginRegistryEntry {
         id: plugin_id.clone(),
         lifecycle_state: PluginLifecycleState::Enabled,
         source: review.source.clone(),
@@ -516,6 +516,15 @@ async fn install_from_staged(
         restart_required: true,
         error: None,
     };
+    if let Err(err) = runtime_plugin_from_entry(packages, validator, entry.clone()).await {
+        let message = format!(
+            "runtime contributions disabled: plugin `{}` is not servable: {err}",
+            plugin_id.as_str()
+        );
+        crate::diag!("[plugins] {message}");
+        entry.lifecycle_state = PluginLifecycleState::Invalid;
+        entry.error = Some(message);
+    }
     registry.upsert(entry.clone());
     registry_store
         .save_registry(&registry)
@@ -525,9 +534,10 @@ async fn install_from_staged(
         plugin_id: plugin_id.clone(),
         version: review.manifest.version.clone(),
     });
-    let _ = mcp
-        .reconcile(active_mcp_specs(packages, validator, &registry).await?)
-        .await;
+    let (active_servers, invalid_plugins) =
+        active_mcp_specs(packages, validator, &registry).await?;
+    persist_invalid_runtime_plugins(registry_store, &mut registry, invalid_plugins).await;
+    let _ = mcp.reconcile(active_servers).await;
     let admin = admin_from_descriptor(
         PluginDescriptor {
             manifest: review.manifest.clone(),
@@ -611,13 +621,11 @@ impl SetPluginEnabled {
                 restart_required: true,
             });
         }
-        let _ = self
-            .mcp
-            .reconcile(
-                active_mcp_specs(self.packages.as_ref(), self.validator.as_ref(), &registry)
-                    .await?,
-            )
+        let (active_servers, invalid_plugins) =
+            active_mcp_specs(self.packages.as_ref(), self.validator.as_ref(), &registry).await?;
+        persist_invalid_runtime_plugins(self.registry.as_ref(), &mut registry, invalid_plugins)
             .await;
+        let _ = self.mcp.reconcile(active_servers).await;
         let descriptor =
             descriptor_for(self.packages.as_ref(), self.validator.as_ref(), saved).await?;
         admin_from_descriptor(descriptor, self.packages.as_ref())
@@ -833,9 +841,11 @@ impl ReconcilePluginMcpServers {
 
     /// Executes the use case.
     pub async fn execute(&self) -> Result<domain::PluginMcpStatusSet, AppError> {
-        let registry = self.registry.load_registry().await.map_err(map_registry)?;
-        let specs =
+        let mut registry = self.registry.load_registry().await.map_err(map_registry)?;
+        let (specs, invalid_plugins) =
             active_mcp_specs(self.packages.as_ref(), self.validator.as_ref(), &registry).await?;
+        persist_invalid_runtime_plugins(self.registry.as_ref(), &mut registry, invalid_plugins)
+            .await;
         self.mcp.reconcile(specs).await.map_err(map_mcp)
     }
 }
@@ -844,7 +854,7 @@ async fn active_mcp_specs(
     packages: &dyn PluginPackageStore,
     validator: &dyn PluginManifestValidator,
     registry: &domain::PluginRegistry,
-) -> Result<Vec<PluginMcpServerSpec>, AppError> {
+) -> Result<(Vec<PluginMcpServerSpec>, Vec<(PluginId, String)>), AppError> {
     let installed_roots = packages
         .list_installed()
         .await
@@ -854,11 +864,23 @@ async fn active_mcp_specs(
         .collect::<std::collections::HashMap<_, _>>();
     let app_data_dir = packages.app_data_dir_label();
     let mut specs = Vec::new();
+    let mut invalid_plugins = Vec::new();
     for entry in &registry.plugins {
         if !entry.lifecycle_state.is_runtime_active() {
             continue;
         }
-        let descriptor = descriptor_for(packages, validator, entry.clone()).await?;
+        let descriptor = match descriptor_for(packages, validator, entry.clone()).await {
+            Ok(descriptor) => descriptor,
+            Err(err) => {
+                let message = format!(
+                    "MCP servers disabled: plugin `{}` is not servable: {err}",
+                    entry.id.as_str()
+                );
+                crate::diag!("[plugins] {message}");
+                invalid_plugins.push((entry.id.clone(), message));
+                continue;
+            }
+        };
         let plugin_root = installed_roots
             .get(&descriptor.manifest.id)
             .cloned()
@@ -907,7 +929,30 @@ async fn active_mcp_specs(
             });
         }
     }
-    Ok(specs)
+    Ok((specs, invalid_plugins))
+}
+
+async fn persist_invalid_runtime_plugins(
+    registry_store: &dyn PluginRegistryStore,
+    registry: &mut domain::PluginRegistry,
+    invalid_plugins: Vec<(PluginId, String)>,
+) {
+    if invalid_plugins.is_empty() {
+        return;
+    }
+    for (plugin_id, message) in invalid_plugins {
+        if let Some(entry) = registry.plugins.iter_mut().find(|p| p.id == plugin_id) {
+            entry.lifecycle_state = PluginLifecycleState::Invalid;
+            entry.error = Some(message);
+        }
+    }
+    if let Err(err) = registry_store
+        .save_registry(registry)
+        .await
+        .map_err(map_registry)
+    {
+        crate::diag!("[plugins] failed to persist invalid runtime plugin state: {err}");
+    }
 }
 
 fn substitute_vars(raw: &str, plugin_root: &str, app_data_dir: Option<&str>) -> String {
@@ -1668,6 +1713,38 @@ mod tests {
         assert!(reconciles[0].is_empty());
     }
 
+    #[tokio::test]
+    async fn reconcile_mcp_marks_invalid_active_plugin_and_keeps_reconcile_alive() {
+        let packages = Arc::new(FakePackages::with_manifest(br#"{"broken":true}"#.to_vec()));
+        let registry = Arc::new(FakeRegistry {
+            registry: Mutex::new(registry_with(PluginLifecycleState::Enabled)),
+        });
+        let mcp = Arc::new(FakeMcp::default());
+        let usecase = ReconcilePluginMcpServers::new(
+            packages,
+            registry.clone(),
+            Arc::new(validator()),
+            mcp.clone(),
+        );
+
+        let statuses = usecase.execute().await.unwrap();
+
+        assert!(statuses.servers.is_empty());
+        assert_eq!(mcp.reconciles.lock().unwrap().len(), 1);
+        assert!(mcp.reconciles.lock().unwrap()[0].is_empty());
+        let saved = registry.load_registry().await.unwrap();
+        let entry = saved.find(&plugin_id()).unwrap();
+        assert_eq!(entry.lifecycle_state, PluginLifecycleState::Invalid);
+        assert!(
+            entry
+                .error
+                .as_deref()
+                .unwrap_or_default()
+                .contains("MCP servers disabled"),
+            "registry must carry a confined MCP error: {entry:?}"
+        );
+    }
+
     #[tokio::test]
     async fn reconcile_mcp_substitutes_app_data_dir_in_plugin_server_specs() {
         let mut manifest: serde_json::Value = serde_json::from_slice(&valid_manifest()).unwrap();
diff --git a/crates/infrastructure/src/plugin/mod.rs b/crates/infrastructure/src/plugin/mod.rs
index b82be10..43732b0 100644
--- a/crates/infrastructure/src/plugin/mod.rs
+++ b/crates/infrastructure/src/plugin/mod.rs
@@ -255,6 +255,7 @@ impl PluginPackageStore for FsPluginPackageStore {
         entry: &RelativePath,
         hash: &ContentHash,
     ) -> Result<PluginBundleUrl, PluginStoreError> {
+        self.resolve_asset_path(plugin_id, entry)?;
         Ok(PluginBundleUrl::new(format!(
             "idea-plugin://{}/current/{}{}{}",
             plugin_id.as_str(),
diff --git a/crates/infrastructure/tests/plugin_install_load.rs b/crates/infrastructure/tests/plugin_install_load.rs
index 1623dc6..1b1b471 100644
--- a/crates/infrastructure/tests/plugin_install_load.rs
+++ b/crates/infrastructure/tests/plugin_install_load.rs
@@ -146,3 +146,77 @@ async fn installs_sdk_hello_plugin_and_loads_runtime_catalog() {
 
     let _ = fs::remove_dir_all(app_data);
 }
+
+#[tokio::test]
+async fn installed_plugin_with_missing_main_is_isolated_from_runtime_catalog() {
+    let app_data = temp_dir("missing-main-app-data");
+    let source = temp_dir("missing-main-source");
+    fs::write(
+        source.join("idea-plugin.json"),
+        r#"{
+          "ideaPluginManifestVersion": 1,
+          "id": "dev.idea.fixtures.missing-main",
+          "displayName": "Missing Main Plugin",
+          "version": "0.1.0",
+          "main": "dist/index.js",
+          "trustLevel": "full",
+          "capabilities": ["ui"],
+          "contributes": {}
+        }"#,
+    )
+    .unwrap();
+    let packages = Arc::new(FsPluginPackageStore::new(&app_data));
+    let registry = Arc::new(FsPluginRegistryStore::new(&app_data));
+    let validator = Arc::new(JsonPluginManifestValidator::new("0.3.0"));
+    let events = Arc::new(TokioBroadcastEventBus::new());
+    let mcp = Arc::new(ExternalMcpPluginSupervisor::new());
+
+    let install = InstallPluginFromDirectory::new(
+        packages.clone(),
+        registry.clone(),
+        validator.clone(),
+        events,
+        mcp,
+    );
+    let result = install
+        .execute(source.to_string_lossy().into_owned())
+        .await
+        .unwrap();
+    assert_eq!(result.plugin.id, "dev.idea.fixtures.missing-main");
+    assert_eq!(
+        result.plugin.lifecycle_state,
+        domain::PluginLifecycleState::Invalid
+    );
+    assert!(result
+        .plugin
+        .error
+        .as_deref()
+        .unwrap_or_default()
+        .contains("not servable"));
+
+    let catalog = ListPluginRuntimeContributions::new(packages, registry.clone(), validator)
+        .execute()
+        .await
+        .unwrap();
+    assert!(catalog.plugins.is_empty());
+    let admin = ListPlugins::new(
+        Arc::new(FsPluginPackageStore::new(&app_data)),
+        registry,
+        Arc::new(JsonPluginManifestValidator::new("0.3.0")),
+    )
+    .execute()
+    .await
+    .unwrap();
+    assert_eq!(
+        admin[0].lifecycle_state,
+        domain::PluginLifecycleState::Invalid
+    );
+    assert!(admin[0]
+        .error
+        .as_deref()
+        .unwrap_or_default()
+        .contains("not servable"));
+
+    let _ = fs::remove_dir_all(source);
+    let _ = fs::remove_dir_all(app_data);
+}