fix: enrich tool activity arguments on dedup

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

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

@@ -319,7 +319,8 @@ public class AgentWorkflowTurnRunner : ITurnWorkflowRunner
                 command,
                 requestInfo,
                 state.ActiveAgent,
-                state.ToolNamesByCallId);
+                state.ToolNamesByCallId,
+                state.ToolCallHasArgumentsById);
 
             if (activity is null)
             {

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

@@ -23,6 +23,8 @@ internal class TurnExecutionState
 
     public ConcurrentDictionary<string, string> ToolNamesByCallId { get; } = new(StringComparer.Ordinal);
 
+    public ConcurrentDictionary<string, bool> ToolCallHasArgumentsById { get; } = new(StringComparer.Ordinal);
+
     public AgentIdentity? ActiveAgent { get; private set; }
 
     public List<ChatMessageDto> CompletedMessages { get; private set; } = [];
@@ -93,7 +95,7 @@ internal class TurnExecutionState
             case ProviderToolExecutionStartEvent toolExecutionStart:
                 string toolCallId = toolExecutionStart.ToolCallId;
                 string toolName = toolExecutionStart.ToolName;
-                ToolNamesByCallId[toolCallId] = toolName;
+                TrackToolCall(toolCallId, toolName, toolExecutionStart.ToolArguments);
                 ActiveAgent = agent;
                 AgentActivityEventDto? toolActivity = CreateToolCallingActivity(
                     agent, toolName, toolCallId, toolExecutionStart.ToolArguments);
@@ -269,6 +271,15 @@ internal class TurnExecutionState
         _lastObservedMessageId = messageId;
     }
 
+    private void TrackToolCall(
+        string toolCallId,
+        string toolName,
+        IReadOnlyDictionary<string, object?>? toolArguments)
+    {
+        ToolNamesByCallId[toolCallId] = toolName;
+        ToolCallHasArgumentsById[toolCallId] = toolArguments is { Count: > 0 };
+    }
+
     private void QueueMessageReclassifiedIfNeeded(string? messageId)
     {
         if (string.IsNullOrWhiteSpace(messageId))

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

@@ -20,7 +20,8 @@ internal static class WorkflowRequestInfoInterpreter
         RunTurnCommandDto command,
         RequestInfoEvent requestInfo,
         AgentIdentity? activeAgent,
-        ConcurrentDictionary<string, string> toolNamesByCallId)
+        ConcurrentDictionary<string, string> toolNamesByCallId,
+        ConcurrentDictionary<string, bool> toolCallHasArgumentsById)
     {
         RequestInterpretation interpretation = InterpretRequest(command.Workflow, requestInfo);
         return interpretation switch
@@ -28,7 +29,7 @@ internal static class WorkflowRequestInfoInterpreter
             HandoffRequestInterpretation handoff =>
                 CreateHandoffActivity(command, handoff.TargetAgent, activeAgent),
             ToolRequestInterpretation tool when activeAgent.HasValue =>
-                CreateToolCallingActivity(command, activeAgent.Value, tool, toolNamesByCallId),
+                CreateToolCallingActivity(command, activeAgent.Value, tool, toolNamesByCallId, toolCallHasArgumentsById),
             _ => null,
         };
     }
@@ -63,14 +64,21 @@ internal static class WorkflowRequestInfoInterpreter
         RunTurnCommandDto command,
         AgentIdentity activeAgent,
         ToolRequestInterpretation tool,
-        ConcurrentDictionary<string, string> toolNamesByCallId)
+        ConcurrentDictionary<string, string> toolNamesByCallId,
+        ConcurrentDictionary<string, bool> toolCallHasArgumentsById)
     {
+        bool hasToolArguments = tool.ToolArguments is { Count: > 0 };
         if (tool.ToolCallId is not null && toolNamesByCallId.ContainsKey(tool.ToolCallId))
         {
-            return null;
+            bool trackedHasArguments = toolCallHasArgumentsById.TryGetValue(tool.ToolCallId, out bool hasTrackedArguments)
+                && hasTrackedArguments;
+            if (trackedHasArguments || !hasToolArguments)
+            {
+                return null;
+            }
         }
 
-        TrackToolCallId(toolNamesByCallId, tool.ToolCallId, tool.ToolName);
+        TrackToolCallId(toolNamesByCallId, toolCallHasArgumentsById, tool.ToolCallId, tool.ToolName, hasToolArguments);
 
         return new AgentActivityEventDto
         {
@@ -88,12 +96,15 @@ internal static class WorkflowRequestInfoInterpreter
 
     private static void TrackToolCallId(
         ConcurrentDictionary<string, string> toolNamesByCallId,
+        ConcurrentDictionary<string, bool> toolCallHasArgumentsById,
         string? toolCallId,
-        string toolName)
+        string toolName,
+        bool hasToolArguments)
     {
         if (toolCallId is not null)
         {
             toolNamesByCallId[toolCallId] = toolName;
+            toolCallHasArgumentsById[toolCallId] = hasToolArguments;
         }
     }
 

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

@@ -78,6 +78,8 @@ public sealed class CopilotTurnExecutionStateTests
         Assert.Equal("/src/main.ts", toolActivity.ToolArguments["path"]);
         Assert.True(state.ToolNamesByCallId.TryGetValue("tool-call-1", out string? toolName));
         Assert.Equal("view", toolName);
+        Assert.True(state.ToolCallHasArgumentsById.TryGetValue("tool-call-1", out bool hasArguments));
+        Assert.True(hasArguments);
     }
 
     [Fact]
@@ -93,6 +95,8 @@ public sealed class CopilotTurnExecutionStateTests
 
         AgentActivityEventDto toolActivity = Assert.Single(state.DrainPendingEvents().OfType<AgentActivityEventDto>());
         Assert.Null(toolActivity.ToolArguments);
+        Assert.True(state.ToolCallHasArgumentsById.TryGetValue("tool-call-1", out bool hasArguments));
+        Assert.False(hasArguments);
     }
 
     [Fact]
@@ -109,6 +113,8 @@ public sealed class CopilotTurnExecutionStateTests
         Assert.Empty(state.DrainPendingEvents().OfType<AgentActivityEventDto>());
         Assert.True(state.ToolNamesByCallId.TryGetValue("tool-call-1", out string? toolName));
         Assert.Equal("handoff_to_specialist", toolName);
+        Assert.True(state.ToolCallHasArgumentsById.TryGetValue("tool-call-1", out bool hasArguments));
+        Assert.False(hasArguments);
     }
 
     [Fact]
@@ -231,6 +237,10 @@ public sealed class CopilotTurnExecutionStateTests
         Assert.Equal("rg", firstToolName);
         Assert.True(state.ToolNamesByCallId.TryGetValue("tool-call-2", out string? secondToolName));
         Assert.Equal("view", secondToolName);
+        Assert.True(state.ToolCallHasArgumentsById.TryGetValue("tool-call-1", out bool firstHasArguments));
+        Assert.False(firstHasArguments);
+        Assert.True(state.ToolCallHasArgumentsById.TryGetValue("tool-call-2", out bool secondHasArguments));
+        Assert.False(secondHasArguments);
     }
 
     [Fact]

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

@@ -721,6 +721,65 @@ public sealed class CopilotWorkflowRunnerTests
             });
     }
 
+    [Fact]
+    public async Task HandleWorkflowEventAsync_EmitsToolActivityEnrichmentWhenRequestInfoAddsMissingArguments()
+    {
+        RunTurnCommandDto command = CreateApprovalCommand();
+        CopilotTurnExecutionState state = new(command);
+        state.ObserveSessionEvent(
+            CreateAgent("agent-1", "Primary"),
+            SessionEvent.FromJson(
+                """
+                {
+                  "type": "tool.execution_start",
+                  "data": {
+                    "toolCallId": "tool-call-1",
+                    "toolName": "view"
+                  },
+                  "id": "f61652d1-120e-4a9f-8f0e-1dbf04fb18da",
+                  "timestamp": "2026-03-27T00:00:00Z"
+                }
+                """));
+        _ = state.DrainPendingEvents();
+
+        RequestInfoEvent requestInfo = CreateRequestInfoEvent(
+            new FunctionCallContent("tool-call-1", "view", new Dictionary<string, object?>
+            {
+                ["path"] = @"C:\workspace\README.md",
+            }));
+        List<AgentActivityEventDto> activities = [];
+
+        MethodInfo handleWorkflowEvent = typeof(CopilotWorkflowRunner).GetMethod(
+            "HandleWorkflowEventAsync",
+            BindingFlags.NonPublic | BindingFlags.Static)!;
+        Task<bool> handleTask = (Task<bool>)handleWorkflowEvent.Invoke(
+            null,
+            [
+                command,
+                requestInfo,
+                Array.Empty<ChatMessage>(),
+                state,
+                (Func<TurnDeltaEventDto, Task>)(_ => Task.CompletedTask),
+                (Func<SidecarEventDto, Task>)(sidecarEvent =>
+                {
+                    activities.Add(Assert.IsType<AgentActivityEventDto>(sidecarEvent));
+                    return Task.CompletedTask;
+                }),
+            ])!;
+
+        bool shouldEndTurn = await handleTask;
+
+        Assert.False(shouldEndTurn);
+        AgentActivityEventDto activity = Assert.Single(activities);
+        Assert.Equal("tool-calling", activity.ActivityType);
+        Assert.Equal("view", activity.ToolName);
+        Assert.Equal("tool-call-1", activity.ToolCallId);
+        Assert.NotNull(activity.ToolArguments);
+        Assert.Equal(@"C:\workspace\README.md", activity.ToolArguments["path"]);
+        Assert.True(state.ToolCallHasArgumentsById.TryGetValue("tool-call-1", out bool hasArguments));
+        Assert.True(hasArguments);
+    }
+
     [Fact]
     public void CreateExecutionEnvironment_UsesLockstepWhenRequested()
     {

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

@@ -15,7 +15,7 @@ public sealed class WorkflowRequestInfoInterpreterTests
     [Fact]
     public void TryCreateActivityFromRequest_ReturnsToolCallingActivityForFunctionCalls()
     {
-        ConcurrentDictionary<string, string> toolNamesByCallId = new(StringComparer.Ordinal);
+        var tracking = CreateToolTracking();
         RequestInfoEvent requestInfo = CreateRequestInfoEvent(
             new FunctionCallContent("call-1", "view", new Dictionary<string, object?>
             {
@@ -27,7 +27,8 @@ public sealed class WorkflowRequestInfoInterpreterTests
             CreateSingleAgentCommand(),
             requestInfo,
             new AgentIdentity("agent-1", "Primary"),
-            toolNamesByCallId);
+            tracking.ToolNamesByCallId,
+            tracking.ToolCallHasArgumentsById);
 
         Assert.NotNull(activity);
         Assert.Equal("tool-calling", activity.ActivityType);
@@ -37,13 +38,14 @@ public sealed class WorkflowRequestInfoInterpreterTests
         Assert.NotNull(activity.ToolArguments);
         Assert.Equal(@"C:\workspace\file.txt", activity.ToolArguments["path"]);
         Assert.Equal([10, 25], Assert.IsAssignableFrom<IReadOnlyList<object?>>(activity.ToolArguments["viewRange"]));
-        Assert.Equal("view", toolNamesByCallId["call-1"]);
+        Assert.Equal("view", tracking.ToolNamesByCallId["call-1"]);
+        Assert.True(tracking.ToolCallHasArgumentsById["call-1"]);
     }
 
     [Fact]
     public void TryCreateActivityFromRequest_MapsMcpToolCalls()
     {
-        ConcurrentDictionary<string, string> toolNamesByCallId = new(StringComparer.Ordinal);
+        var tracking = CreateToolTracking();
         RequestInfoEvent requestInfo = CreateRequestInfoEvent(
             CreateMcpToolCall(
                 "call-1",
@@ -59,7 +61,8 @@ public sealed class WorkflowRequestInfoInterpreterTests
             CreateSingleAgentCommand(),
             requestInfo,
             new AgentIdentity("agent-1", "Primary"),
-            toolNamesByCallId);
+            tracking.ToolNamesByCallId,
+            tracking.ToolCallHasArgumentsById);
 
         Assert.NotNull(activity);
         Assert.Equal("tool-calling", activity.ActivityType);
@@ -67,13 +70,14 @@ public sealed class WorkflowRequestInfoInterpreterTests
         Assert.NotNull(activity.ToolArguments);
         Assert.Equal(@"C:\workspace", activity.ToolArguments["path"]);
         Assert.Equal(true, activity.ToolArguments["includeIgnored"]);
-        Assert.Equal("git.status", toolNamesByCallId["call-1"]);
+        Assert.Equal("git.status", tracking.ToolNamesByCallId["call-1"]);
+        Assert.True(tracking.ToolCallHasArgumentsById["call-1"]);
     }
 
     [Fact]
     public void TryCreateActivityFromRequest_MapsCodeInterpreterCallsToSyntheticToolName()
     {
-        ConcurrentDictionary<string, string> toolNamesByCallId = new(StringComparer.Ordinal);
+        var tracking = CreateToolTracking();
         RequestInfoEvent requestInfo = CreateRequestInfoEvent(
             CreateCodeInterpreterToolCall("call-1", "print('hello')"));
 
@@ -81,7 +85,8 @@ public sealed class WorkflowRequestInfoInterpreterTests
             CreateSingleAgentCommand(),
             requestInfo,
             new AgentIdentity("agent-1", "Primary"),
-            toolNamesByCallId);
+            tracking.ToolNamesByCallId,
+            tracking.ToolCallHasArgumentsById);
 
         Assert.NotNull(activity);
         Assert.Equal("tool-calling", activity.ActivityType);
@@ -90,32 +95,35 @@ public sealed class WorkflowRequestInfoInterpreterTests
         Assert.Equal(
             ["print('hello')"],
             Assert.IsAssignableFrom<IReadOnlyList<object?>>(activity.ToolArguments["inputs"]));
-        Assert.Equal("code interpreter", toolNamesByCallId["call-1"]);
+        Assert.Equal("code interpreter", tracking.ToolNamesByCallId["call-1"]);
+        Assert.True(tracking.ToolCallHasArgumentsById["call-1"]);
     }
 
     [Fact]
     public void TryCreateActivityFromRequest_MapsImageGenerationCallsWithoutTrackingCallId()
     {
-        ConcurrentDictionary<string, string> toolNamesByCallId = new(StringComparer.Ordinal);
+        var tracking = CreateToolTracking();
         RequestInfoEvent requestInfo = CreateRequestInfoEvent(CreateImageGenerationToolCall());
 
         AgentActivityEventDto? activity = WorkflowRequestInfoInterpreter.TryCreateActivityFromRequest(
             CreateSingleAgentCommand(),
             requestInfo,
             new AgentIdentity("agent-1", "Primary"),
-            toolNamesByCallId);
+            tracking.ToolNamesByCallId,
+            tracking.ToolCallHasArgumentsById);
 
         Assert.NotNull(activity);
         Assert.Equal("tool-calling", activity.ActivityType);
         Assert.Equal("image generation", activity.ToolName);
         Assert.Null(activity.ToolArguments);
-        Assert.Empty(toolNamesByCallId);
+        Assert.Empty(tracking.ToolNamesByCallId);
+        Assert.Empty(tracking.ToolCallHasArgumentsById);
     }
 
     [Fact]
     public void TryCreateActivityFromRequest_LeavesToolArgumentsNullWhenFunctionCallHasNoUsableArguments()
     {
-        ConcurrentDictionary<string, string> toolNamesByCallId = new(StringComparer.Ordinal);
+        var tracking = CreateToolTracking();
         RequestInfoEvent requestInfo = CreateRequestInfoEvent(
             new FunctionCallContent("call-1", "view", new Dictionary<string, object?>
             {
@@ -127,16 +135,18 @@ public sealed class WorkflowRequestInfoInterpreterTests
             CreateSingleAgentCommand(),
             requestInfo,
             new AgentIdentity("agent-1", "Primary"),
-            toolNamesByCallId);
+            tracking.ToolNamesByCallId,
+            tracking.ToolCallHasArgumentsById);
 
         Assert.NotNull(activity);
         Assert.Null(activity.ToolArguments);
+        Assert.False(tracking.ToolCallHasArgumentsById["call-1"]);
     }
 
     [Fact]
     public void TryCreateActivityFromRequest_TruncatesOversizedToolArgumentValues()
     {
-        ConcurrentDictionary<string, string> toolNamesByCallId = new(StringComparer.Ordinal);
+        var tracking = CreateToolTracking();
         RequestInfoEvent requestInfo = CreateRequestInfoEvent(
             new FunctionCallContent(
                 "call-1",
@@ -150,37 +160,71 @@ public sealed class WorkflowRequestInfoInterpreterTests
             CreateSingleAgentCommand(),
             requestInfo,
             new AgentIdentity("agent-1", "Primary"),
-            toolNamesByCallId);
+            tracking.ToolNamesByCallId,
+            tracking.ToolCallHasArgumentsById);
 
         Assert.NotNull(activity);
         Assert.NotNull(activity.ToolArguments);
         Assert.Equal("[truncated]", activity.ToolArguments["command"]);
+        Assert.True(tracking.ToolCallHasArgumentsById["call-1"]);
     }
 
     [Fact]
-    public void TryCreateActivityFromRequest_SkipsDuplicateTrackedToolCallIds()
+    public void TryCreateActivityFromRequest_SkipsDuplicateTrackedToolCallIdsThatAlreadyHaveArguments()
     {
-        ConcurrentDictionary<string, string> toolNamesByCallId = new(StringComparer.Ordinal)
+        var tracking = CreateToolTracking();
-        {
+        tracking.ToolNamesByCallId["call-1"] = "view";
-            ["call-1"] = "view",
+        tracking.ToolCallHasArgumentsById["call-1"] = true;
-        };
         RequestInfoEvent requestInfo = CreateRequestInfoEvent(
-            new FunctionCallContent("call-1", "view", new Dictionary<string, object?>()));
+            new FunctionCallContent("call-1", "view", new Dictionary<string, object?>
+            {
+                ["path"] = @"C:\workspace\file.txt",
+            }));
 
         AgentActivityEventDto? activity = WorkflowRequestInfoInterpreter.TryCreateActivityFromRequest(
             CreateSingleAgentCommand(),
             requestInfo,
             new AgentIdentity("agent-1", "Primary"),
-            toolNamesByCallId);
+            tracking.ToolNamesByCallId,
+            tracking.ToolCallHasArgumentsById);
 
         Assert.Null(activity);
-        Assert.Equal("view", toolNamesByCallId["call-1"]);
+        Assert.Equal("view", tracking.ToolNamesByCallId["call-1"]);
+        Assert.True(tracking.ToolCallHasArgumentsById["call-1"]);
+    }
+
+    [Fact]
+    public void TryCreateActivityFromRequest_EmitsEnrichmentWhenTrackedToolCallWasMissingArguments()
+    {
+        var tracking = CreateToolTracking();
+        tracking.ToolNamesByCallId["call-1"] = "view";
+        tracking.ToolCallHasArgumentsById["call-1"] = false;
+        RequestInfoEvent requestInfo = CreateRequestInfoEvent(
+            new FunctionCallContent("call-1", "view", new Dictionary<string, object?>
+            {
+                ["path"] = @"C:\workspace\file.txt",
+            }));
+
+        AgentActivityEventDto? activity = WorkflowRequestInfoInterpreter.TryCreateActivityFromRequest(
+            CreateSingleAgentCommand(),
+            requestInfo,
+            new AgentIdentity("agent-1", "Primary"),
+            tracking.ToolNamesByCallId,
+            tracking.ToolCallHasArgumentsById);
+
+        Assert.NotNull(activity);
+        Assert.Equal("tool-calling", activity.ActivityType);
+        Assert.Equal("call-1", activity.ToolCallId);
+        Assert.NotNull(activity.ToolArguments);
+        Assert.Equal(@"C:\workspace\file.txt", activity.ToolArguments["path"]);
+        Assert.Equal("view", tracking.ToolNamesByCallId["call-1"]);
+        Assert.True(tracking.ToolCallHasArgumentsById["call-1"]);
     }
 
     [Fact]
     public void TryCreateActivityFromRequest_ReturnsHandoffActivityForKnownTargets()
     {
-        ConcurrentDictionary<string, string> toolNamesByCallId = new(StringComparer.Ordinal);
+        var tracking = CreateToolTracking();
         RequestInfoEvent requestInfo = CreateRequestInfoEvent(
             CreateHandoffTarget("agent-handoff-ux", "UX Specialist"));
 
@@ -188,7 +232,8 @@ public sealed class WorkflowRequestInfoInterpreterTests
             CreateHandoffCommand(),
             requestInfo,
             new AgentIdentity("agent-handoff-triage", "Triage"),
-            toolNamesByCallId);
+            tracking.ToolNamesByCallId,
+            tracking.ToolCallHasArgumentsById);
 
         Assert.NotNull(activity);
         Assert.Equal("handoff", activity.ActivityType);
@@ -197,7 +242,8 @@ public sealed class WorkflowRequestInfoInterpreterTests
         Assert.Equal("agent-handoff-triage", activity.SourceAgentId);
         Assert.Equal("Triage", activity.SourceAgentName);
         Assert.Null(activity.ToolName);
-        Assert.Empty(toolNamesByCallId);
+        Assert.Empty(tracking.ToolNamesByCallId);
+        Assert.Empty(tracking.ToolCallHasArgumentsById);
     }
 
     [Fact]
@@ -295,6 +341,11 @@ public sealed class WorkflowRequestInfoInterpreterTests
             CreateAgent("agent-handoff-ux", "UX Specialist"),
         ]);
 
+    private static (
+        ConcurrentDictionary<string, string> ToolNamesByCallId,
+        ConcurrentDictionary<string, bool> ToolCallHasArgumentsById) CreateToolTracking()
+        => (new(StringComparer.Ordinal), new(StringComparer.Ordinal));
+
     private static RunTurnCommandDto CreateCommand(string orchestrationMode, IReadOnlyList<WorkflowNodeDto> agents)
     {
         return new RunTurnCommandDto