fix: auto-allow infrastructure tool hooks

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

sidecar/src/Aryx.AgentHost/Services/CopilotSessionHooks.cs

@@ -7,9 +7,19 @@ namespace Aryx.AgentHost.Services;
 
 internal static class CopilotSessionHooks
 {
+    private const string AskUserToolName = "ask_user";
     private const string AllowDecision = "allow";
     private const string AskDecision = "ask";
     private const string DenyDecision = "deny";
+    private const string HandoffToolPrefix = "handoff_to_";
+    private const string ReportIntentToolName = "report_intent";
+    private const string TaskCompleteToolName = "task_complete";
+    private static readonly HashSet<string> AlwaysAllowedToolNames = new(StringComparer.OrdinalIgnoreCase)
+    {
+        AskUserToolName,
+        ReportIntentToolName,
+        TaskCompleteToolName,
+    };
     private static readonly JsonSerializerOptions HookJsonOptions = new(JsonSerializerDefaults.Web)
     {
         DefaultIgnoreCondition = JsonIgnoreCondition.WhenWritingNull,
@@ -216,11 +226,20 @@ internal static class CopilotSessionHooks
         PatternAgentDefinitionDto agentDefinition,
         PreToolUseHookInput input)
     {
+        string? toolName = Normalize(input.ToolName);
+        if (IsAlwaysAllowedTool(toolName))
+        {
+            return new PreToolUseHookOutput
+            {
+                PermissionDecision = AllowDecision,
+            };
+        }
+
         bool requiresApproval = CopilotApprovalCoordinator.RequiresToolCallApproval(
             command.Pattern.ApprovalPolicy,
             agentDefinition.Id,
-            Normalize(input.ToolName),
+            toolName,
-            Normalize(input.ToolName));
+            toolName);
 
         return new PreToolUseHookOutput
         {
@@ -262,6 +281,14 @@ internal static class CopilotSessionHooks
     private static string SerializeHookValue(object? value)
         => JsonSerializer.Serialize(value, HookJsonOptions);
 
+    private static bool IsAlwaysAllowedTool(string? toolName)
+    {
+        string? normalizedToolName = Normalize(toolName);
+        return normalizedToolName is not null
+            && (AlwaysAllowedToolNames.Contains(normalizedToolName)
+                || normalizedToolName.StartsWith(HandoffToolPrefix, StringComparison.OrdinalIgnoreCase));
+    }
+
     private static string? Normalize(string? value)
         => string.IsNullOrWhiteSpace(value) ? null : value.Trim();
 

sidecar/tests/Aryx.AgentHost.Tests/CopilotSessionHooksTests.cs

@@ -106,6 +106,27 @@ public sealed class CopilotSessionHooksTests
         Assert.Single(runner.Invocations);
     }
 
+    [Theory]
+    [InlineData("ask_user")]
+    [InlineData("report_intent")]
+    [InlineData("task_complete")]
+    [InlineData("handoff_to_2")]
+    [InlineData("handoff_to_specialist")]
+    public async Task Create_PreToolUseAutoAllowsInfrastructureTools(string toolName)
+    {
+        RunTurnCommandDto command = CreateCommandWithToolApproval();
+        SessionHooks hooks = CopilotSessionHooks.Create(command, command.Pattern.Agents[0], ResolvedHookSet.Empty, new RecordingHookCommandRunner());
+
+        PreToolUseHookOutput? decision = await hooks.OnPreToolUse!(
+            new PreToolUseHookInput
+            {
+                ToolName = toolName,
+            },
+            null!);
+
+        Assert.Equal("allow", decision?.PermissionDecision);
+    }
+
     [Fact]
     public async Task Create_RunsConfiguredNonPreToolHooks()
     {