Fail cleanly when AppHost selection needs a prompt in non-interactive mode (#17619)

src/Aspire.Cli/Backchannel/AppHostConnectionResolver.cs

@@ -43,6 +43,7 @@ internal sealed class AppHostConnectionResolver(
     IInteractionService interactionService,
     IProjectLocator projectLocator,
     CliExecutionContext executionContext,
+    ICliHostEnvironment hostEnvironment,
     ILogger logger,
     ProfilingTelemetry? profilingTelemetry = null)
 {
@@ -199,6 +200,17 @@ public async Task<AppHostConnectionResult> ResolveConnectionAsync(
         }
         else if (inScopeConnections.Count > 1)
         {
+            if (!hostEnvironment.SupportsInteractiveInput)
+            {
+                // Can't prompt the user to pick an AppHost in non-interactive mode;
+                // fail with an actionable message instead of letting the prompt throw.
+                return new AppHostConnectionResult
+                {
+                    ErrorMessage = SharedCommandStrings.MultipleAppHostsNonInteractive,
+                    ExitCode = CliExitCodes.FailedToFindProject,
+                };
+            }
+
             selectedConnection = await PromptForAppHostSelectionAsync(
                 inScopeConnections,
                 SharedCommandStrings.MultipleInScopeAppHosts,
@@ -208,6 +220,18 @@ public async Task<AppHostConnectionResult> ResolveConnectionAsync(
         }
         else if (outOfScopeConnections.Count > 0)
         {
+            if (!hostEnvironment.SupportsInteractiveInput)
+            {
+                // No in-scope AppHosts, and selecting from out-of-scope AppHosts requires
+                // a prompt. In non-interactive mode treat this as "not found" so scripts
+                // get a clean error and exit code instead of an unexpected prompt failure.
+                return new AppHostConnectionResult
+                {
+                    ErrorMessage = notFoundMessage,
+                    ExitCode = CliExitCodes.FailedToFindProject,
+                };
+            }
+
             selectedConnection = await PromptForAppHostSelectionAsync(
                 outOfScopeConnections,
                 SharedCommandStrings.NoInScopeAppHostsShowingAll,

src/Aspire.Cli/Commands/CommonCommandServices.cs

@@ -16,7 +16,8 @@ internal sealed class CommonCommandServices(
     IInteractionService interactionService,
     AspireCliTelemetry telemetry,
     ConsoleCancellationManager cancellationManager,
-    ILoggerFactory loggerFactory)
+    ILoggerFactory loggerFactory,
+    ICliHostEnvironment hostEnvironment)
 {
     public IFeatures Features { get; } = features;
     public ICliUpdateNotifier UpdateNotifier { get; } = updateNotifier;
@@ -25,4 +26,5 @@ internal sealed class CommonCommandServices(
     public AspireCliTelemetry Telemetry { get; } = telemetry;
     public ConsoleCancellationManager CancellationManager { get; } = cancellationManager;
     public ILoggerFactory LoggerFactory { get; } = loggerFactory;
+    public ICliHostEnvironment HostEnvironment { get; } = hostEnvironment;
 }

src/Aspire.Cli/Commands/DescribeCommand.cs

@@ -111,7 +111,7 @@ public DescribeCommand(
     {
         Aliases.Add("resources");
         _resourceColorMap = resourceColorMap;
-        _connectionResolver = new AppHostConnectionResolver(backchannelMonitor, InteractionService, projectLocator, services.ExecutionContext, logger);
+        _connectionResolver = new AppHostConnectionResolver(backchannelMonitor, InteractionService, projectLocator, services.ExecutionContext, services.HostEnvironment, logger);
 
         Arguments.Add(s_resourceArgument);
         Options.Add(s_appHostOption);

src/Aspire.Cli/Commands/ExportCommand.cs

@@ -61,7 +61,7 @@ public ExportCommand(
         _httpClientFactory = httpClientFactory;
         _timeProvider = timeProvider;
         _logger = logger;
-        _connectionResolver = new AppHostConnectionResolver(backchannelMonitor, InteractionService, projectLocator, services.ExecutionContext, logger);
+        _connectionResolver = new AppHostConnectionResolver(backchannelMonitor, InteractionService, projectLocator, services.ExecutionContext, services.HostEnvironment, logger);
 
         Arguments.Add(s_resourceArgument);
         Options.Add(s_appHostOption);

src/Aspire.Cli/Commands/LogsCommand.cs

@@ -128,7 +128,7 @@ public LogsCommand(
         _resourceColorMap = resourceColorMap;
         _hostEnvironment = hostEnvironment;
         _logger = logger;
-        _connectionResolver = new AppHostConnectionResolver(backchannelMonitor, InteractionService, projectLocator, services.ExecutionContext, logger, profilingTelemetry);
+        _connectionResolver = new AppHostConnectionResolver(backchannelMonitor, InteractionService, projectLocator, services.ExecutionContext, services.HostEnvironment, logger, profilingTelemetry);
 
         Arguments.Add(s_resourceArgument);
         Options.Add(s_appHostOption);

src/Aspire.Cli/Commands/McpCallCommand.cs

@@ -45,7 +45,7 @@ public McpCallCommand(
         CommonCommandServices services)
         : base("call", McpCommandStrings.CallCommand_Description, services)
     {
-        _connectionResolver = new AppHostConnectionResolver(backchannelMonitor, InteractionService, projectLocator, services.ExecutionContext, logger);
+        _connectionResolver = new AppHostConnectionResolver(backchannelMonitor, InteractionService, projectLocator, services.ExecutionContext, services.HostEnvironment, logger);
 
         Arguments.Add(s_resourceArgument);
         Arguments.Add(s_toolArgument);

src/Aspire.Cli/Commands/McpToolsCommand.cs

@@ -35,7 +35,7 @@ public McpToolsCommand(
         CommonCommandServices services)
         : base("tools", McpCommandStrings.ToolsCommand_Description, services)
     {
-        _connectionResolver = new AppHostConnectionResolver(backchannelMonitor, InteractionService, projectLocator, services.ExecutionContext, logger);
+        _connectionResolver = new AppHostConnectionResolver(backchannelMonitor, InteractionService, projectLocator, services.ExecutionContext, services.HostEnvironment, logger);
 
         Options.Add(s_appHostOption);
         Options.Add(s_formatOption);

src/Aspire.Cli/Commands/ResourceCommand.cs

@@ -82,7 +82,7 @@ public ResourceCommand(
     {
         _backchannelMonitor = backchannelMonitor;
         _projectLocator = projectLocator;
-        _connectionResolver = new AppHostConnectionResolver(backchannelMonitor, InteractionService, projectLocator, services.ExecutionContext, logger);
+        _connectionResolver = new AppHostConnectionResolver(backchannelMonitor, InteractionService, projectLocator, services.ExecutionContext, services.HostEnvironment, logger);
         _logger = logger;
 
         Arguments.Add(s_resourceArgument);

src/Aspire.Cli/Commands/StopCommand.cs

@@ -44,7 +44,7 @@ public StopCommand(
         CommonCommandServices services)
         : base("stop", StopCommandStrings.Description, services)
     {
-        _connectionResolver = new AppHostConnectionResolver(backchannelMonitor, interactionService, projectLocator, services.ExecutionContext, logger, profilingTelemetry);
+        _connectionResolver = new AppHostConnectionResolver(backchannelMonitor, interactionService, projectLocator, services.ExecutionContext, services.HostEnvironment, logger, profilingTelemetry);
         _hostEnvironment = hostEnvironment;
         _processShutdownService = processShutdownService;
         _logger = logger;

src/Aspire.Cli/Commands/TelemetryLogsCommand.cs

@@ -64,7 +64,7 @@ public TelemetryLogsCommand(
         _resourceColorMap = resourceColorMap;
         _timeProvider = timeProvider;
         _logger = logger;
-        _connectionResolver = new AppHostConnectionResolver(backchannelMonitor, interactionService, projectLocator, services.ExecutionContext, logger);
+        _connectionResolver = new AppHostConnectionResolver(backchannelMonitor, interactionService, projectLocator, services.ExecutionContext, services.HostEnvironment, logger);
 
         Arguments.Add(s_resourceArgument);
         Options.Add(s_appHostOption);

src/Aspire.Cli/Commands/TelemetrySpansCommand.cs

@@ -54,7 +54,7 @@ public TelemetrySpansCommand(
         _resourceColorMap = resourceColorMap;
         _timeProvider = timeProvider;
         _logger = logger;
-        _connectionResolver = new AppHostConnectionResolver(backchannelMonitor, InteractionService, projectLocator, services.ExecutionContext, logger);
+        _connectionResolver = new AppHostConnectionResolver(backchannelMonitor, InteractionService, projectLocator, services.ExecutionContext, services.HostEnvironment, logger);
 
         Arguments.Add(s_resourceArgument);
         Options.Add(s_appHostOption);

src/Aspire.Cli/Commands/TelemetryTracesCommand.cs

@@ -54,7 +54,7 @@ public TelemetryTracesCommand(
         _resourceColorMap = resourceColorMap;
         _timeProvider = timeProvider;
         _logger = logger;
-        _connectionResolver = new AppHostConnectionResolver(backchannelMonitor, InteractionService, projectLocator, services.ExecutionContext, logger);
+        _connectionResolver = new AppHostConnectionResolver(backchannelMonitor, InteractionService, projectLocator, services.ExecutionContext, services.HostEnvironment, logger);
 
         Arguments.Add(s_resourceArgument);
         Options.Add(s_appHostOption);

src/Aspire.Cli/Commands/TerminalAttachCommand.cs

@@ -66,7 +66,7 @@ public TerminalAttachCommand(
     {
         _interactionService = services.InteractionService;
         _logger = logger;
-        _connectionResolver = new AppHostConnectionResolver(backchannelMonitor, services.InteractionService, projectLocator, services.ExecutionContext, logger);
+        _connectionResolver = new AppHostConnectionResolver(backchannelMonitor, services.InteractionService, projectLocator, services.ExecutionContext, services.HostEnvironment, logger);
 
         Arguments.Add(s_resourceArgument);
         Options.Add(s_appHostOption);

src/Aspire.Cli/Commands/TerminalPsCommand.cs

@@ -63,7 +63,7 @@ public TerminalPsCommand(
     {
         _interactionService = services.InteractionService;
         _logger = logger;
-        _connectionResolver = new AppHostConnectionResolver(backchannelMonitor, services.InteractionService, projectLocator, services.ExecutionContext, logger);
+        _connectionResolver = new AppHostConnectionResolver(backchannelMonitor, services.InteractionService, projectLocator, services.ExecutionContext, services.HostEnvironment, logger);
 
         Options.Add(s_appHostOption);
         Options.Add(s_formatOption);

src/Aspire.Cli/Commands/WaitCommand.cs

@@ -47,7 +47,7 @@ public WaitCommand(
         TimeProvider? timeProvider = null)
         : base("wait", WaitCommandStrings.Description, services)
     {
-        _connectionResolver = new AppHostConnectionResolver(backchannelMonitor, InteractionService, projectLocator, ExecutionContext, logger);
+        _connectionResolver = new AppHostConnectionResolver(backchannelMonitor, InteractionService, projectLocator, ExecutionContext, services.HostEnvironment, logger);
         _logger = logger;
         _timeProvider = timeProvider ?? TimeProvider.System;
 

src/Aspire.Cli/Resources/SharedCommandStrings.resx

@@ -182,6 +182,9 @@
   <data name="MultipleInScopeAppHosts" xml:space="preserve">
     <value>Multiple running AppHosts found in the current directory. Select from running AppHosts.</value>
   </data>
+  <data name="MultipleAppHostsNonInteractive" xml:space="preserve">
+    <value>Multiple running AppHosts were found, but the CLI is running in non-interactive mode. Pass --apphost to specify which AppHost to use.</value>
+  </data>
   <data name="PromptRunAgentInit" xml:space="preserve">
     <value>Would you like to configure AI agent environments for this project?</value>
   </data>