diff --git a/desktop/src-tauri/src/commands/agent_discovery.rs b/desktop/src-tauri/src/commands/agent_discovery.rs
index 35462cffc..fe82aaf42 100644
--- a/desktop/src-tauri/src/commands/agent_discovery.rs
+++ b/desktop/src-tauri/src/commands/agent_discovery.rs
@@ -20,9 +20,16 @@ fn active_installs() -> &'static std::sync::Mutex<std::collections::HashSet<Stri
 }
 
 #[tauri::command]
-pub fn discover_acp_providers() -> Vec<AcpRuntimeCatalogEntry> {
-    crate::managed_agents::clear_resolve_cache();
-    crate::managed_agents::discover_acp_runtimes()
+pub async fn discover_acp_providers() -> Result<Vec<AcpRuntimeCatalogEntry>, String> {
+    // Discovery spawns login shells to resolve each runtime binary, which can
+    // take seconds. Run it off the main thread so the webview stays responsive
+    // (sync Tauri commands block the main thread).
+    tokio::task::spawn_blocking(|| {
+        crate::managed_agents::clear_resolve_cache();
+        crate::managed_agents::discover_acp_runtimes()
+    })
+    .await
+    .map_err(|e| format!("runtime discovery task panicked: {e}"))
 }
 
 #[tauri::command]
@@ -292,26 +299,32 @@ fn floor_char_boundary(s: &str, mut index: usize) -> usize {
 }
 
 #[tauri::command]
-pub fn discover_managed_agent_prereqs(
+pub async fn discover_managed_agent_prereqs(
     input: DiscoverManagedAgentPrereqsRequest,
-) -> ManagedAgentPrereqsInfo {
-    let acp_command = input
-        .acp_command
-        .as_deref()
-        .map(str::trim)
-        .filter(|value| !value.is_empty())
-        .unwrap_or(DEFAULT_ACP_COMMAND);
-    let mcp_command = input
-        .mcp_command
-        .as_deref()
-        .map(str::trim)
-        .filter(|value| !value.is_empty())
-        .unwrap_or("");
+) -> Result<ManagedAgentPrereqsInfo, String> {
+    // Command resolution can spawn a login shell on cache miss — keep it off
+    // the main thread so the webview stays responsive.
+    tokio::task::spawn_blocking(move || {
+        let acp_command = input
+            .acp_command
+            .as_deref()
+            .map(str::trim)
+            .filter(|value| !value.is_empty())
+            .unwrap_or(DEFAULT_ACP_COMMAND);
+        let mcp_command = input
+            .mcp_command
+            .as_deref()
+            .map(str::trim)
+            .filter(|value| !value.is_empty())
+            .unwrap_or("");
 
-    ManagedAgentPrereqsInfo {
-        acp: command_availability(acp_command),
-        mcp: command_availability(mcp_command),
-    }
+        ManagedAgentPrereqsInfo {
+            acp: command_availability(acp_command),
+            mcp: command_availability(mcp_command),
+        }
+    })
+    .await
+    .map_err(|e| format!("prereq discovery task panicked: {e}"))
 }
 
 #[tauri::command]
diff --git a/desktop/src-tauri/src/commands/agent_providers.rs b/desktop/src-tauri/src/commands/agent_providers.rs
index a903e4bba..acdd46ac6 100644
--- a/desktop/src-tauri/src/commands/agent_providers.rs
+++ b/desktop/src-tauri/src/commands/agent_providers.rs
@@ -1,14 +1,20 @@
 use crate::managed_agents::{discover_provider_candidates, invoke_provider, BackendProviderInfo};
 
 #[tauri::command]
-pub fn discover_backend_providers() -> Vec<BackendProviderInfo> {
-    discover_provider_candidates()
-        .into_iter()
-        .map(|(id, path)| BackendProviderInfo {
-            id,
-            binary_path: path.display().to_string(),
-        })
-        .collect()
+pub async fn discover_backend_providers() -> Result<Vec<BackendProviderInfo>, String> {
+    // PATH scanning hits the filesystem for every directory — run it off the
+    // main thread so the webview stays responsive.
+    tokio::task::spawn_blocking(|| {
+        discover_provider_candidates()
+            .into_iter()
+            .map(|(id, path)| BackendProviderInfo {
+                id,
+                binary_path: path.display().to_string(),
+            })
+            .collect()
+    })
+    .await
+    .map_err(|e| format!("provider discovery task panicked: {e}"))
 }
 
 #[tauri::command]
diff --git a/desktop/src/features/agents/ui/CreateAgentDialog.tsx b/desktop/src/features/agents/ui/CreateAgentDialog.tsx
index 12bc81700..ba8200fb4 100644
--- a/desktop/src/features/agents/ui/CreateAgentDialog.tsx
+++ b/desktop/src/features/agents/ui/CreateAgentDialog.tsx
@@ -1,4 +1,4 @@
-import { AlertTriangle, ChevronDown } from "lucide-react";
+import { AlertTriangle, ChevronDown, Loader2 } from "lucide-react";
 import * as React from "react";
 
 import {
@@ -791,6 +791,9 @@ export function CreateAgentDialog({
               size="sm"
               type="button"
             >
+              {isDiscoveryPending ? (
+                <Loader2 aria-hidden className="h-4 w-4 animate-spin" />
+              ) : null}
               {meshPreparing
                 ? "Connecting to mesh..."
                 : createMutation.isPending