fix: filter internal runtime tools

Exclude internal runtime tools from sidecar capability discovery so they do not surface in the approval tool catalog.

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

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

@@ -16,6 +16,13 @@ public sealed class SidecarProtocolHost
     private const string ResolveApprovalCommandType = "resolve-approval";
     private const string ResolveUserInputCommandType = "resolve-user-input";
     private const string AskUserToolName = "ask_user";
+    private static readonly HashSet<string> ExcludedRuntimeToolNames = new(StringComparer.OrdinalIgnoreCase)
+    {
+        AskUserToolName,
+        "report_intent",
+        "task_complete",
+        "exit_plan_mode",
+    };
 
     private static readonly string[] AuthenticationErrorIndicators =
     [
@@ -460,7 +467,7 @@ public sealed class SidecarProtocolHost
     {
         string? toolName = string.IsNullOrWhiteSpace(tool.Name) ? null : tool.Name.Trim();
         return toolName is not null
-            && !string.Equals(toolName, AskUserToolName, StringComparison.OrdinalIgnoreCase);
+            && !ExcludedRuntimeToolNames.Contains(toolName);
     }
 
     private static bool IsReasoningEffort(string? value)

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

@@ -517,7 +517,7 @@ public sealed class SidecarProtocolHostTests
     }
 
     [Fact]
-    public void MapRuntimeTools_ExcludesAskUserAndDeduplicatesByName()
+    public void MapRuntimeTools_ExcludesInternalToolsAndDeduplicatesByName()
     {
         IReadOnlyList<SidecarRuntimeToolDto> runtimeTools = SidecarProtocolHost.MapRuntimeTools(
         [
@@ -527,6 +527,21 @@ public sealed class SidecarProtocolHostTests
                 Description = "Ask the user a question.",
             },
             new Tool
+            {
+                Name = "report_intent",
+                Description = "Report current intent.",
+            },
+            new Tool
+            {
+                Name = "task_complete",
+                Description = "Signal task completion.",
+            },
+            new Tool
+            {
+                Name = "exit_plan_mode",
+                Description = "Exit plan mode.",
+            },
+            new Tool
             {
                 Name = " web_fetch ",
                 Description = " Fetch content from the web. ",