diff --git a/dotnet/src/Microsoft.Agents.AI.Workflows.Declarative/ObjectModel/InvokeFunctionToolExecutor.cs b/dotnet/src/Microsoft.Agents.AI.Workflows.Declarative/ObjectModel/InvokeFunctionToolExecutor.cs
index e40d53ede7..06981b6b24 100644
--- a/dotnet/src/Microsoft.Agents.AI.Workflows.Declarative/ObjectModel/InvokeFunctionToolExecutor.cs
+++ b/dotnet/src/Microsoft.Agents.AI.Workflows.Declarative/ObjectModel/InvokeFunctionToolExecutor.cs
@@ -171,7 +171,7 @@ internal sealed class InvokeFunctionToolExecutor(
                     this.Logger.LogWarning(
                         "Approval response '{RequestId}' did not match any pending invocation on '{ActionId}'.",
                         approval.RequestId, this.Id);
-                    await this.AssignErrorAsync(context, "Function invocation was not approved by user.").ConfigureAwait(false);
+                    await this.AssignErrorAsync(context, "No pending approval matched the response.").ConfigureAwait(false);
                 }
                 else if (!approval.Approved)
                 {
@@ -184,11 +184,10 @@ internal sealed class InvokeFunctionToolExecutor(
                 }
                 else
                 {
-                    // Snapshot was consumed by a concurrent delivery; surface the not-approved error.
                     this.Logger.LogWarning(
                         "Approval response '{RequestId}' had no remaining pending snapshot on '{ActionId}'.",
                         approval.RequestId, this.Id);
-                    await this.AssignErrorAsync(context, "Function invocation was not approved by user.").ConfigureAwait(false);
+                    await this.AssignErrorAsync(context, "No pending approval matched the response.").ConfigureAwait(false);
                 }
             }
         }
diff --git a/dotnet/src/Microsoft.Agents.AI.Workflows.Declarative/ObjectModel/InvokeMcpToolExecutor.cs b/dotnet/src/Microsoft.Agents.AI.Workflows.Declarative/ObjectModel/InvokeMcpToolExecutor.cs
index c384084898..e6e740b4e6 100644
--- a/dotnet/src/Microsoft.Agents.AI.Workflows.Declarative/ObjectModel/InvokeMcpToolExecutor.cs
+++ b/dotnet/src/Microsoft.Agents.AI.Workflows.Declarative/ObjectModel/InvokeMcpToolExecutor.cs
@@ -149,14 +149,15 @@ internal sealed class InvokeMcpToolExecutor(
             .OfType<ToolApprovalResponseContent>()
             .FirstOrDefault(r => this._approvalSnapshots.ContainsKey(r.RequestId));
 
-        if (approvalResponse?.Approved != true)
+        if (approvalResponse is null)
         {
-            // Rejected, no matching pending, or unknown request id: surface a not-approved
-            // error and drop any matched snapshot.
-            if (approvalResponse is not null)
-            {
-                this._approvalSnapshots.TryRemove(approvalResponse.RequestId, out _);
-            }
+            await this.AssignErrorAsync(context, "No pending approval matched the response.").ConfigureAwait(false);
+            return;
+        }
+
+        if (!approvalResponse.Approved)
+        {
+            this._approvalSnapshots.TryRemove(approvalResponse.RequestId, out _);
             await this.AssignErrorAsync(context, "MCP tool invocation was not approved by user.").ConfigureAwait(false);
             return;
         }
@@ -165,7 +166,7 @@ internal sealed class InvokeMcpToolExecutor(
         // Headers are re-evaluated (they may contain auth secrets not persisted to state).
         if (!this._approvalSnapshots.TryRemove(approvalResponse.RequestId, out ApprovalSnapshot? snapshot))
         {
-            await this.AssignErrorAsync(context, "MCP tool invocation was not approved by user.").ConfigureAwait(false);
+            await this.AssignErrorAsync(context, "No pending approval matched the response.").ConfigureAwait(false);
             return;
         }
 
diff --git a/dotnet/tests/Microsoft.Agents.AI.Workflows.Declarative.UnitTests/ObjectModel/InvokeFunctionToolExecutorTest.cs b/dotnet/tests/Microsoft.Agents.AI.Workflows.Declarative.UnitTests/ObjectModel/InvokeFunctionToolExecutorTest.cs
index 17d5d80575..b14e4d7520 100644
--- a/dotnet/tests/Microsoft.Agents.AI.Workflows.Declarative.UnitTests/ObjectModel/InvokeFunctionToolExecutorTest.cs
+++ b/dotnet/tests/Microsoft.Agents.AI.Workflows.Declarative.UnitTests/ObjectModel/InvokeFunctionToolExecutorTest.cs
@@ -905,7 +905,7 @@ public sealed class InvokeFunctionToolExecutorTest(ITestOutputHelper output) : W
             i.Method.Name == nameof(IWorkflowContext.QueueStateUpdateAsync)
             && i.Arguments.Count >= 2
             && i.Arguments[1] is StringValue sv
-            && sv.Value.Contains("not approved by user"));
+            && sv.Value.Contains("No pending approval"));
     }
 
     /// <summary>
@@ -1003,13 +1003,13 @@ public sealed class InvokeFunctionToolExecutorTest(ITestOutputHelper output) : W
         // Act
         await action.CaptureResponseAsync(mockContext.Object, response, CancellationToken.None);
 
-        // Assert - the valid approval drove invocation; no not-approved error was assigned.
+        // Assert - the valid approval drove invocation; no error was assigned.
         Assert.True(functionWasInvoked);
         Assert.DoesNotContain(mockContext.Invocations, i =>
             i.Method.Name == nameof(IWorkflowContext.QueueStateUpdateAsync)
             && i.Arguments.Count >= 2
             && i.Arguments[1] is StringValue sv
-            && sv.Value.Contains("not approved by user"));
+            && sv.Value.StartsWith("Error:", StringComparison.Ordinal));
     }
 
     /// <summary>
@@ -1050,12 +1050,12 @@ public sealed class InvokeFunctionToolExecutorTest(ITestOutputHelper output) : W
 
         // Assert - the registered AIFunction was invoked exactly once.
         Assert.Equal(1, invocationCount);
-        // The second delivery surfaced the not-approved error path.
+        // The second delivery surfaced the no-pending-approval error.
         Assert.Contains(mockContext.Invocations, i =>
             i.Method.Name == nameof(IWorkflowContext.QueueStateUpdateAsync)
             && i.Arguments.Count >= 2
             && i.Arguments[1] is StringValue sv
-            && sv.Value.Contains("not approved by user"));
+            && sv.Value.Contains("No pending approval"));
     }
 
     /// <summary>
@@ -1090,7 +1090,7 @@ public sealed class InvokeFunctionToolExecutorTest(ITestOutputHelper output) : W
         await action.CaptureResponseAsync(mockContext.Object, response, CancellationToken.None);
 
         // Assert - the host-computed result was assigned to Output.Result and no
-        // not-approved error was emitted.
+        // error was emitted.
         Assert.Contains(mockContext.Invocations, i =>
             i.Method.Name == nameof(IWorkflowContext.QueueStateUpdateAsync)
             && i.Arguments.Count >= 2
@@ -1100,7 +1100,7 @@ public sealed class InvokeFunctionToolExecutorTest(ITestOutputHelper output) : W
             i.Method.Name == nameof(IWorkflowContext.QueueStateUpdateAsync)
             && i.Arguments.Count >= 2
             && i.Arguments[1] is StringValue sv
-            && sv.Value.Contains("not approved by user"));
+            && sv.Value.StartsWith("Error:", StringComparison.Ordinal));
     }
 
     /// <summary>
diff --git a/dotnet/tests/Microsoft.Agents.AI.Workflows.Declarative.UnitTests/ObjectModel/InvokeMcpToolExecutorTest.cs b/dotnet/tests/Microsoft.Agents.AI.Workflows.Declarative.UnitTests/ObjectModel/InvokeMcpToolExecutorTest.cs
index ba66b31d09..bb34b6c9a2 100644
--- a/dotnet/tests/Microsoft.Agents.AI.Workflows.Declarative.UnitTests/ObjectModel/InvokeMcpToolExecutorTest.cs
+++ b/dotnet/tests/Microsoft.Agents.AI.Workflows.Declarative.UnitTests/ObjectModel/InvokeMcpToolExecutorTest.cs
@@ -1585,8 +1585,7 @@ public sealed class InvokeMcpToolExecutorTest(ITestOutputHelper output) : Workfl
 
     /// <summary>
     /// Builds an approval response paired to the request id stamped on the emitted
-    /// <c>MCPToolApprovalRequestContent</c>. Mirrors the framework's symmetric
-    /// content-id rewriting at the envelope boundary.
+    /// <c>ToolApprovalRequestContent</c>.
     /// </summary>
     private static ExternalInputResponse CreateApprovalResponseFor(IReadOnlyList<ExternalInputRequest> emittedRequests, bool approved)
     {