.NET: fix inline skill string arguments

dotnet/src/Microsoft.Agents.AI/Skills/Programmatic/AgentInlineSkillScript.cs

@@ -92,18 +92,50 @@ private static AIFunctionArguments ConvertToFunctionArguments(JsonElement? argum
             return [];
         }
 
-        if (arguments.Value.ValueKind != JsonValueKind.Object)
+        var argumentElement = arguments.Value;
+        using var parsedStringArguments = ParseStringArguments(argumentElement);
+        if (parsedStringArguments is not null)
+        {
+            argumentElement = parsedStringArguments.RootElement;
+        }
+
+        if (argumentElement.ValueKind != JsonValueKind.Object)
         {
             throw new InvalidOperationException(
-                $"Inline skill scripts expect arguments as a JSON object but received a JSON element of kind '{arguments.Value.ValueKind}'.");
+                $"Inline skill scripts expect arguments as a JSON object but received a JSON element of kind '{argumentElement.ValueKind}'.");
         }
 
         var dict = new Dictionary<string, object?>();
-        foreach (var property in arguments.Value.EnumerateObject())
+        foreach (var property in argumentElement.EnumerateObject())
         {
-            dict[property.Name] = property.Value;
+            dict[property.Name] = parsedStringArguments is null ? property.Value : property.Value.Clone();
         }
 
         return new AIFunctionArguments(dict);
     }
+
+    private static JsonDocument? ParseStringArguments(JsonElement arguments)
+    {
+        if (arguments.ValueKind != JsonValueKind.String)
+        {
+            return null;
+        }
+
+        var json = arguments.GetString();
+        if (string.IsNullOrWhiteSpace(json))
+        {
+            return null;
+        }
+
+        try
+        {
+            return JsonDocument.Parse(json);
+        }
+        catch (JsonException ex)
+        {
+            throw new InvalidOperationException(
+                "Inline skill scripts received arguments as a JSON string, but the string did not contain valid JSON.",
+                ex);
+        }
+    }
 }

dotnet/tests/Microsoft.Agents.AI.UnitTests/AgentSkills/AgentInlineSkillScriptTests.cs

@@ -43,6 +43,22 @@ public async Task RunAsync_WithParameters_PassesArgumentsAsync()
         Assert.Equal(10, int.Parse(result?.ToString()!));
     }
 
+    [Fact]
+    public async Task RunAsync_WithStringEncodedObjectArguments_PassesArgumentsAsync()
+    {
+        // Arrange
+        var script = new AgentInlineSkillScript("add", (int a, int b) => a + b);
+        var skill = new AgentInlineSkill("calc-skill", "Calc.", "Instructions.");
+        using var argsDoc = JsonDocument.Parse("\"{\\\"a\\\":3,\\\"b\\\":7}\"");
+        var args = argsDoc.RootElement;
+
+        // Act
+        var result = await script.RunAsync(skill, args, null, CancellationToken.None);
+
+        // Assert
+        Assert.Equal(10, int.Parse(result?.ToString()!));
+    }
+
     [Fact]
     public void ParametersSchema_NoParameters_ReturnsSchema()
     {