Stop suppressing existing format handling

Author: stephentoub

src/Libraries/Microsoft.Extensions.AI.Abstractions/Utilities/AIJsonUtilities.Schema.Create.cs

@@ -41,8 +41,8 @@ public static partial class AIJsonUtilities
     private const string AdditionalPropertiesPropertyName = "additionalProperties";
     private const string DefaultPropertyName = "default";
     private const string RefPropertyName = "$ref";
-    private const string FormatPropertyName = "format";
 #if NET
+    private const string FormatPropertyName = "format";
     private const string ContentEncodingPropertyName = "contentEncoding";
     private const string ContentMediaTypePropertyName = "contentMediaType";
     private const string MinLengthStringPropertyName = "minLength";
@@ -58,10 +58,6 @@ public static partial class AIJsonUtilities
     /// <summary>The uri used when populating the $schema keyword in created schemas.</summary>
     private const string SchemaKeywordUri = "https://json-schema.org/draft/2020-12/schema";
 
-    // List of keywords used by JsonSchemaExporter but explicitly disallowed by some AI vendors.
-    // cf. https://platform.openai.com/docs/guides/structured-outputs#some-type-specific-keywords-are-not-yet-supported
-    private static readonly string[] _schemaKeywordsDisallowedByAIVendors = ["minLength", "maxLength", "pattern", "format"];
-
     /// <summary>
     /// Determines a JSON schema for the provided method.
     /// </summary>
@@ -296,12 +292,6 @@ JsonNode TransformSchemaNode(JsonSchemaExporterContext schemaExporterContext, Js
                     objSchema.InsertAtStart(TypePropertyName, new JsonArray { (JsonNode)"string", (JsonNode)"null" });
                 }
 
-                // Filter potentially disallowed keywords.
-                foreach (string keyword in _schemaKeywordsDisallowedByAIVendors)
-                {
-                    _ = objSchema.Remove(keyword);
-                }
-
                 // Some consumers of the JSON schema, including Ollama as of v0.3.13, don't understand
                 // schemas with "type": [...], and only understand "type" being a single value.
                 // In certain configurations STJ represents .NET numeric types as ["string", "number"], which will then lead to an error.
@@ -334,7 +324,6 @@ JsonNode TransformSchemaNode(JsonSchemaExporterContext schemaExporterContext, Js
                 ConvertSchemaToObject(ref schema).InsertAtStart(SchemaPropertyName, (JsonNode)SchemaKeywordUri);
             }
 
-            ApplyDataTypeFormats(parameterName, ref schema, ctx);
             ApplyDataAnnotations(parameterName, ref schema, ctx);
 
             // Finally, apply any user-defined transformations if specified.
@@ -365,43 +354,6 @@ static JsonObject ConvertSchemaToObject(ref JsonNode schema)
                 }
             }
 
-            static void ApplyDataTypeFormats(string? parameterName, ref JsonNode schema, AIJsonSchemaCreateContext ctx)
-            {
-                Type t = ctx.TypeInfo.Type;
-
-                if (Nullable.GetUnderlyingType(t) is { } underlyingType)
-                {
-                    t = underlyingType;
-                }
-
-                if (t == typeof(DateTime) || t == typeof(DateTimeOffset))
-                {
-                    ConvertSchemaToObject(ref schema)[FormatPropertyName] = "date-time";
-                }
-#if NET
-                else if (t == typeof(DateOnly))
-                {
-                    ConvertSchemaToObject(ref schema)[FormatPropertyName] = "date";
-                }
-                else if (t == typeof(TimeOnly))
-                {
-                    ConvertSchemaToObject(ref schema)[FormatPropertyName] = "time";
-                }
-#endif
-                else if (t == typeof(TimeSpan))
-                {
-                    ConvertSchemaToObject(ref schema)[FormatPropertyName] = "duration";
-                }
-                else if (t == typeof(Guid))
-                {
-                    ConvertSchemaToObject(ref schema)[FormatPropertyName] = "uuid";
-                }
-                else if (t == typeof(Uri))
-                {
-                    ConvertSchemaToObject(ref schema)[FormatPropertyName] = "uri";
-                }
-            }
-
             void ApplyDataAnnotations(string? parameterName, ref JsonNode schema, AIJsonSchemaCreateContext ctx)
             {
                 if (ctx.GetCustomAttribute<DisplayNameAttribute>() is { } displayNameAttribute)
@@ -613,10 +565,6 @@ static JsonArray CreateJsonArray(object?[] values, JsonSerializerOptions seriali
                             obj[FormatPropertyName] ??= "time";
                             break;
 
-                        case DataType.Duration:
-                            obj[FormatPropertyName] ??= "duration";
-                            break;
-
                         case DataType.EmailAddress:
                             obj[FormatPropertyName] ??= "email";
                             break;

test/Libraries/Microsoft.Extensions.AI.Abstractions.Tests/Utilities/AIJsonUtilitiesTests.cs

@@ -405,6 +405,7 @@ public static void CreateJsonSchema_ValidateWithTestData(ITestData testData)
         JsonElement schema = AIJsonUtilities.CreateJsonSchema(testData.Type, serializerOptions: options, inferenceOptions: createOptions);
         JsonNode? schemaAsNode = JsonSerializer.SerializeToNode(schema, options);
 
+        // NOTE: This is not validating the schemas match, only that they have the same top-level kind.
         Assert.NotNull(schemaAsNode);
         Assert.Equal(testData.ExpectedJsonSchema.GetValueKind(), schemaAsNode.GetValueKind());
 
@@ -474,7 +475,7 @@ public static void CreateJsonSchema_IncorporatesTypesAndAnnotations()
                     "TimeSpanProp": {
                         "$comment": "Represents a System.TimeSpan value.",
                         "type": "string",
-                        "format": "duration"
+                        "pattern": "^-?(\\d+\\.)?\\d{2}:\\d{2}:\\d{2}(\\.\\d{1,7})?$"
                     },
                     "GuidProp": {
                         "type": "string",
@@ -579,13 +580,6 @@ public static void CreateJsonSchema_IncorporatesTypesAndAnnotations()
                         ],
                         "format": "time"
                     },
-                    "DataTypeDurationProp": {
-                        "type": [
-                            "string",
-                            "null"
-                        ],
-                        "format": "duration"
-                    },
                     "DataTypeEmailProp": {
                         "type": [
                             "string",
@@ -703,7 +697,7 @@ public static void CreateJsonSchema_IncorporatesTypesAndAnnotations()
                     "TimeSpanProp": {
                         "$comment": "Represents a System.TimeSpan value.",
                         "type": "string",
-                        "format": "duration"
+                        "pattern": "^-?(\\d+\\.)?\\d{2}:\\d{2}:\\d{2}(\\.\\d{1,7})?$"
                     },
                     "GuidProp": {
                         "type": "string",
@@ -776,9 +770,6 @@ private sealed class CreateJsonSchema_IncorporatesTypesAndAnnotations_Type
         [DataType(DataType.Time)]
         public string? DataTypeTimeProp { get; set; }
 
-        [DataType(DataType.Duration)]
-        public string? DataTypeDurationProp { get; set; }
-
         [DataType(DataType.EmailAddress)]
         public string? DataTypeEmailProp { get; set; }