diff --git a/src/SwaggerProvider.DesignTime/DefinitionCompiler.fs b/src/SwaggerProvider.DesignTime/DefinitionCompiler.fs
index 24c4dca2..a9606bb0 100644
--- a/src/SwaggerProvider.DesignTime/DefinitionCompiler.fs
+++ b/src/SwaggerProvider.DesignTime/DefinitionCompiler.fs
@@ -281,22 +281,26 @@ type DefinitionCompiler(schema: OpenApiDocument, provideNullable, useDateOnly: b
                     ty.AddXmlDoc schemaObj.Description
 
                 // Combine composite schemas
+                // Cache the isEmpty check to avoid iterating `allOf` twice (once per field/required block).
+                let allOfEmpty = Seq.isEmpty allOf
+
                 let schemaObjProperties =
                     let getProps(s: IOpenApiSchema) =
                         s.Properties |> toSeq
 
-                    match Seq.isEmpty allOf with
-                    | false -> allOf |> Seq.append [ schemaObj ] |> Seq.collect getProps
-                    | true -> getProps schemaObj
-
+                    if allOfEmpty then
+                        getProps schemaObj
+                    else
+                        allOf |> Seq.append [ schemaObj ] |> Seq.collect getProps
 
                 let schemaObjRequired =
                     let getReq(s: IOpenApiSchema) =
                         s.Required |> toSeq
 
-                    match Seq.isEmpty allOf with
-                    | false -> allOf |> Seq.append [ schemaObj ] |> Seq.collect getReq
-                    | true -> getReq schemaObj
+                    if allOfEmpty then
+                        getReq schemaObj
+                    else
+                        allOf |> Seq.append [ schemaObj ] |> Seq.collect getReq
                     |> Set.ofSeq
 
                 // Helper to check if a schema has the Null type flag (OpenAPI 3.0 nullable)
diff --git a/src/SwaggerProvider.Runtime/ProvidedApiClientBase.fs b/src/SwaggerProvider.Runtime/ProvidedApiClientBase.fs
index 4c45032c..b8913b0a 100644
--- a/src/SwaggerProvider.Runtime/ProvidedApiClientBase.fs
+++ b/src/SwaggerProvider.Runtime/ProvidedApiClientBase.fs
@@ -72,12 +72,14 @@ type ProvidedApiClientBase(httpClient: HttpClient, options: JsonSerializerOption
                             return ""
                     }
 
-                match errorCodes |> Array.tryFindIndex((=) codeStr) with
-                | Some idx ->
-                    let desc = errorDescriptions[idx]
+                // Use Array.IndexOf to avoid allocating a partial-application closure on every error response.
+                let errorIdx = System.Array.IndexOf(errorCodes, codeStr)
+
+                if errorIdx >= 0 then
+                    let desc = errorDescriptions[errorIdx]
                     let! body = readBody()
                     return raise(OpenApiException(code, desc, response.Headers, response.Content, body))
-                | None ->
+                else
                     let! body = readBody()
 
                     let desc =
diff --git a/tests/SwaggerProvider.Tests/Schema.V3SchemaCompilationTests.fs b/tests/SwaggerProvider.Tests/Schema.V3SchemaCompilationTests.fs
index 89e23356..a38c9203 100644
--- a/tests/SwaggerProvider.Tests/Schema.V3SchemaCompilationTests.fs
+++ b/tests/SwaggerProvider.Tests/Schema.V3SchemaCompilationTests.fs
@@ -107,3 +107,137 @@ let ``anyOf single $ref resolves to the referenced type``() =
 let ``anyOf single $ref does not produce a separate wrapper type``() =
     let types = compileV3Schema anyOfSingleRefSchema false
     types |> List.exists(fun t -> t.Name = "CatRef") |> shouldEqual false
+
+// ── Required vs optional properties ──────────────────────────────────────────
+
+[<Fact>]
+let ``required property compiles to non-option type``() =
+    let schema =
+        """{
+  "openapi": "3.0.0",
+  "info": { "title": "Test", "version": "1.0.0" },
+  "paths": {},
+  "components": {
+    "schemas": {
+      "Order": {
+        "type": "object",
+        "required": ["id"],
+        "properties": {
+          "id":   { "type": "integer" },
+          "note": { "type": "string" }
+        }
+      }
+    }
+  }
+}"""
+
+    let types = compileV3Schema schema false
+    let orderType = types |> List.find(fun t -> t.Name = "Order")
+    // 'id' is required → int32 (not option)
+    orderType.GetDeclaredProperty("Id").PropertyType
+    |> shouldEqual typeof<int32>
+
+[<Fact>]
+let ``optional property compiles to option type``() =
+    let schema =
+        """{
+  "openapi": "3.0.0",
+  "info": { "title": "Test", "version": "1.0.0" },
+  "paths": {},
+  "components": {
+    "schemas": {
+      "Order": {
+        "type": "object",
+        "required": ["id"],
+        "properties": {
+          "id":   { "type": "integer" },
+          "note": { "type": "string" }
+        }
+      }
+    }
+  }
+}"""
+
+    let types = compileV3Schema schema false
+    let orderType = types |> List.find(fun t -> t.Name = "Order")
+    // 'note' is not required → string option
+    orderType.GetDeclaredProperty("Note").PropertyType
+    |> shouldEqual typeof<string option>
+
+// ── String enum compilation ────────────────────────────────────────────────────
+
+[<Fact>]
+let ``string enum schema compiles to a named enum type``() =
+    let schema =
+        """{
+  "openapi": "3.0.0",
+  "info": { "title": "Test", "version": "1.0.0" },
+  "paths": {},
+  "components": {
+    "schemas": {
+      "Status": {
+        "type": "string",
+        "enum": ["active", "inactive", "pending"]
+      }
+    }
+  }
+}"""
+
+    let types = compileV3Schema schema false
+    types |> List.exists(fun t -> t.Name = "Status") |> shouldEqual true
+
+[<Fact>]
+let ``string enum type is an enum``() =
+    let schema =
+        """{
+  "openapi": "3.0.0",
+  "info": { "title": "Test", "version": "1.0.0" },
+  "paths": {},
+  "components": {
+    "schemas": {
+      "Status": {
+        "type": "string",
+        "enum": ["active", "inactive", "pending"]
+      }
+    }
+  }
+}"""
+
+    let types = compileV3Schema schema false
+    let statusType = types |> List.find(fun t -> t.Name = "Status")
+    statusType.IsEnum |> shouldEqual true
+
+// ── Schema description as XmlDoc ─────────────────────────────────────────────
+
+[<Fact>]
+let ``object schema description is surfaced as XmlDoc``() =
+    let schema =
+        """{
+  "openapi": "3.0.0",
+  "info": { "title": "Test", "version": "1.0.0" },
+  "paths": {},
+  "components": {
+    "schemas": {
+      "Widget": {
+        "type": "object",
+        "description": "A widget with a name",
+        "properties": {
+          "name": { "type": "string" }
+        }
+      }
+    }
+  }
+}"""
+
+    let types = compileV3Schema schema false
+    let widgetType = types |> List.find(fun t -> t.Name = "Widget")
+    // XmlDoc is accessible via GetCustomAttributesData on the provided type
+    let doc = widgetType.GetCustomAttributesData()
+
+    doc
+    |> Seq.exists(fun a ->
+        a.AttributeType.Name = "TypeProviderXmlDocAttribute"
+        && a.ConstructorArguments.Count > 0
+        && a.ConstructorArguments.[0].Value :? string
+        && (a.ConstructorArguments.[0].Value :?> string).Contains("A widget with a name"))
+    |> shouldEqual true