refactor: simplify workflow request interpretation

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

sidecar/tests/Eryx.AgentHost.Tests/ExperimentalOptIns.cs

@@ -0,0 +1,5 @@
+using System.Diagnostics.CodeAnalysis;
+
+[assembly: Experimental(
+    "MEAI001",
+    UrlFormat = "https://aka.ms/dotnet-extensions-warnings/{0}")]

sidecar/tests/Eryx.AgentHost.Tests/WorkflowRequestInfoInterpreterTests.cs

@@ -31,6 +31,25 @@ public sealed class WorkflowRequestInfoInterpreterTests
         Assert.Equal("view", toolNamesByCallId["call-1"]);
     }
 
+    [Fact]
+    public void TryCreateActivityFromRequest_MapsMcpToolCalls()
+    {
+        ConcurrentDictionary<string, string> toolNamesByCallId = new(StringComparer.Ordinal);
+        RequestInfoEvent requestInfo = CreateRequestInfoEvent(
+            CreateMcpToolCall("call-1", "git.status", "Git MCP"));
+
+        AgentActivityEventDto? activity = WorkflowRequestInfoInterpreter.TryCreateActivityFromRequest(
+            CreateSingleAgentCommand(),
+            requestInfo,
+            new AgentIdentity("agent-1", "Primary"),
+            toolNamesByCallId);
+
+        Assert.NotNull(activity);
+        Assert.Equal("tool-calling", activity.ActivityType);
+        Assert.Equal("git.status", activity.ToolName);
+        Assert.Equal("git.status", toolNamesByCallId["call-1"]);
+    }
+
     [Fact]
     public void TryCreateActivityFromRequest_MapsCodeInterpreterCallsToSyntheticToolName()
     {
@@ -159,6 +178,14 @@ public sealed class WorkflowRequestInfoInterpreterTests
         return instance;
     }
 
+    private static object CreateMcpToolCall(string callId, string toolName, string serverName)
+    {
+        Type type = Type.GetType(
+            "Microsoft.Extensions.AI.McpServerToolCallContent, Microsoft.Extensions.AI.Abstractions",
+            throwOnError: true)!;
+        return Activator.CreateInstance(type, callId, toolName, serverName)!;
+    }
+
     private static object CreateImageGenerationToolCall()
     {
         Type type = Type.GetType(