diff --git a/objectivec/GPBDescriptor.h b/objectivec/GPBDescriptor.h
index 360afe9..651f4de 100644
--- a/objectivec/GPBDescriptor.h
+++ b/objectivec/GPBDescriptor.h
@@ -34,113 +34,255 @@
 
 @class GPBEnumDescriptor;
 @class GPBFieldDescriptor;
-@class GPBFieldOptions;
 @class GPBFileDescriptor;
 @class GPBOneofDescriptor;
 
 NS_ASSUME_NONNULL_BEGIN
 
-typedef NS_ENUM(NSInteger, GPBFileSyntax) {
+/** Syntax used in the proto file. */
+typedef NS_ENUM(uint8_t, GPBFileSyntax) {
+  /** Unknown syntax. */
   GPBFileSyntaxUnknown = 0,
+  /** Proto2 syntax. */
   GPBFileSyntaxProto2 = 2,
+  /** Proto3 syntax. */
   GPBFileSyntaxProto3 = 3,
 };
 
-typedef NS_ENUM(NSInteger, GPBFieldType) {
-  GPBFieldTypeSingle,    // optional/required
-  GPBFieldTypeRepeated,  // repeated
-  GPBFieldTypeMap,       // map<K,V>
+/** Type of proto field. */
+typedef NS_ENUM(uint8_t, GPBFieldType) {
+  /** Optional/required field. Only valid for proto2 fields. */
+  GPBFieldTypeSingle,
+  /** Repeated field. */
+  GPBFieldTypeRepeated,
+  /** Map field. */
+  GPBFieldTypeMap,
 };
 
+/**
+ * Describes a proto message.
+ **/
 @interface GPBDescriptor : NSObject<NSCopying>
 
+/** Name of the message. */
 @property(nonatomic, readonly, copy) NSString *name;
-@property(nonatomic, readonly, strong, nullable) NSArray *fields;
-@property(nonatomic, readonly, strong, nullable) NSArray *oneofs;
-@property(nonatomic, readonly, strong, nullable) NSArray *enums;
+/** Fields declared in the message. */
+@property(nonatomic, readonly, strong, nullable) NSArray<GPBFieldDescriptor*> *fields;
+/** Oneofs declared in the message. */
+@property(nonatomic, readonly, strong, nullable) NSArray<GPBOneofDescriptor*> *oneofs;
+/** Extension range declared for the message. */
 @property(nonatomic, readonly, nullable) const GPBExtensionRange *extensionRanges;
-@property(nonatomic, readonly) NSUInteger extensionRangesCount;
+/** Number of extension ranges declared for the message. */
+@property(nonatomic, readonly) uint32_t extensionRangesCount;
+/** Descriptor for the file where the message was defined. */
 @property(nonatomic, readonly, assign) GPBFileDescriptor *file;
 
+/** Whether the message is in wire format or not. */
 @property(nonatomic, readonly, getter=isWireFormat) BOOL wireFormat;
+/** The class of this message. */
 @property(nonatomic, readonly) Class messageClass;
+/** Containing message descriptor if this message is nested, or nil otherwise. */
+@property(readonly, nullable) GPBDescriptor *containingType;
+/**
+ * Fully qualified name for this message (package.message). Can be nil if the
+ * value is unable to be computed.
+ */
+@property(readonly, nullable) NSString *fullName;
 
+/**
+ * Gets the field for the given number.
+ *
+ * @param fieldNumber The number for the field to get.
+ *
+ * @return The field descriptor for the given number, or nil if not found.
+ **/
 - (nullable GPBFieldDescriptor *)fieldWithNumber:(uint32_t)fieldNumber;
+
+/**
+ * Gets the field for the given name.
+ *
+ * @param name The name for the field to get.
+ *
+ * @return The field descriptor for the given name, or nil if not found.
+ **/
 - (nullable GPBFieldDescriptor *)fieldWithName:(NSString *)name;
+
+/**
+ * Gets the oneof for the given name.
+ *
+ * @param name The name for the oneof to get.
+ *
+ * @return The oneof descriptor for the given name, or nil if not found.
+ **/
 - (nullable GPBOneofDescriptor *)oneofWithName:(NSString *)name;
-- (nullable GPBEnumDescriptor *)enumWithName:(NSString *)name;
 
 @end
 
+/**
+ * Describes a proto file.
+ **/
 @interface GPBFileDescriptor : NSObject
 
+/** The package declared in the proto file. */
 @property(nonatomic, readonly, copy) NSString *package;
+/** The objc prefix declared in the proto file. */
+@property(nonatomic, readonly, copy, nullable) NSString *objcPrefix;
+/** The syntax of the proto file. */
 @property(nonatomic, readonly) GPBFileSyntax syntax;
 
 @end
 
+/**
+ * Describes a oneof field.
+ **/
 @interface GPBOneofDescriptor : NSObject
+/** Name of the oneof field. */
 @property(nonatomic, readonly) NSString *name;
-@property(nonatomic, readonly) NSArray *fields;
+/** Fields declared in the oneof. */
+@property(nonatomic, readonly) NSArray<GPBFieldDescriptor*> *fields;
 
+/**
+ * Gets the field for the given number.
+ *
+ * @param fieldNumber The number for the field to get.
+ *
+ * @return The field descriptor for the given number, or nil if not found.
+ **/
 - (nullable GPBFieldDescriptor *)fieldWithNumber:(uint32_t)fieldNumber;
+
+/**
+ * Gets the field for the given name.
+ *
+ * @param name The name for the field to get.
+ *
+ * @return The field descriptor for the given name, or nil if not found.
+ **/
 - (nullable GPBFieldDescriptor *)fieldWithName:(NSString *)name;
+
 @end
 
+/**
+ * Describes a proto field.
+ **/
 @interface GPBFieldDescriptor : NSObject
 
+/** Name of the field. */
 @property(nonatomic, readonly, copy) NSString *name;
+/** Number associated with the field. */
 @property(nonatomic, readonly) uint32_t number;
+/** Data type contained in the field. */
 @property(nonatomic, readonly) GPBDataType dataType;
+/** Whether it has a default value or not. */
 @property(nonatomic, readonly) BOOL hasDefaultValue;
+/** Default value for the field. */
 @property(nonatomic, readonly) GPBGenericValue defaultValue;
+/** Whether this field is required. Only valid for proto2 fields. */
 @property(nonatomic, readonly, getter=isRequired) BOOL required;
+/** Whether this field is optional. */
 @property(nonatomic, readonly, getter=isOptional) BOOL optional;
+/** Type of field (single, repeated, map). */
 @property(nonatomic, readonly) GPBFieldType fieldType;
-// If it is a map, the value type is in -type.
+/** Type of the key if the field is a map. The value's type is -fieldType. */
 @property(nonatomic, readonly) GPBDataType mapKeyDataType;
+/** Whether the field is packable. */
 @property(nonatomic, readonly, getter=isPackable) BOOL packable;
 
+/** The containing oneof if this field is part of one, nil otherwise. */
 @property(nonatomic, readonly, assign, nullable) GPBOneofDescriptor *containingOneof;
 
-@property(nonatomic, readonly, nullable) GPBFieldOptions *fieldOptions;
-
-// Message properties
+/** Class of the message if the field is of message type. */
 @property(nonatomic, readonly, assign, nullable) Class msgClass;
 
-// Enum properties
+/** Descriptor for the enum if this field is an enum. */
 @property(nonatomic, readonly, strong, nullable) GPBEnumDescriptor *enumDescriptor;
 
+/**
+ * Checks whether the given enum raw value is a valid enum value.
+ *
+ * @param value The raw enum value to check.
+ *
+ * @return YES if value is a valid enum raw value.
+ **/
 - (BOOL)isValidEnumValue:(int32_t)value;
 
-// For now, this will return nil if it doesn't know the name to use for
-// TextFormat.
+/** @return Name for the text format, or nil if not known. */
 - (nullable NSString *)textFormatName;
 
 @end
 
+/**
+ * Describes a proto enum.
+ **/
 @interface GPBEnumDescriptor : NSObject
 
+/** Name of the enum. */
 @property(nonatomic, readonly, copy) NSString *name;
+/** Function that validates that raw values are valid enum values. */
 @property(nonatomic, readonly) GPBEnumValidationFunc enumVerifier;
 
+/**
+ * Returns the enum value name for the given raw enum.
+ *
+ * @param number The raw enum value.
+ *
+ * @return The name of the enum value passed, or nil if not valid.
+ **/
 - (nullable NSString *)enumNameForValue:(int32_t)number;
+
+/**
+ * Gets the enum raw value for the given enum name.
+ *
+ * @param outValue A pointer where the value will be set.
+ * @param name     The enum name for which to get the raw value.
+ *
+ * @return YES if a value was copied into the pointer, NO otherwise.
+ **/
 - (BOOL)getValue:(nullable int32_t *)outValue forEnumName:(NSString *)name;
 
+/**
+ * Returns the text format for the given raw enum value.
+ *
+ * @param number The raw enum value.
+ *
+ * @return The text format name for the raw enum value, or nil if not valid.
+ **/
 - (nullable NSString *)textFormatNameForValue:(int32_t)number;
 
+/**
+ * Gets the enum raw value for the given text format name.
+ *
+ * @param outValue       A pointer where the value will be set.
+ * @param textFormatName The text format name for which to get the raw value.
+ *
+ * @return YES if a value was copied into the pointer, NO otherwise.
+ **/
+- (BOOL)getValue:(nullable int32_t *)outValue forEnumTextFormatName:(NSString *)textFormatName;
+
 @end
 
+/**
+ * Describes a proto extension.
+ **/
 @interface GPBExtensionDescriptor : NSObject<NSCopying>
+/** Field number under which the extension is stored. */
 @property(nonatomic, readonly) uint32_t fieldNumber;
+/** The containing message class, i.e. the class extended by this extension. */
 @property(nonatomic, readonly) Class containingMessageClass;
+/** Data type contained in the extension. */
 @property(nonatomic, readonly) GPBDataType dataType;
+/** Whether the extension is repeated. */
 @property(nonatomic, readonly, getter=isRepeated) BOOL repeated;
+/** Whether the extension is packable. */
 @property(nonatomic, readonly, getter=isPackable) BOOL packable;
+/** The class of the message if the extension is of message type. */
 @property(nonatomic, readonly, assign) Class msgClass;
+/** The singleton name for the extension. */
 @property(nonatomic, readonly) NSString *singletonName;
+/** The enum descriptor if the extension is of enum type. */
 @property(nonatomic, readonly, strong, nullable) GPBEnumDescriptor *enumDescriptor;
-@property(nonatomic, readonly) id defaultValue;
+/** The default value for the extension. */
+@property(nonatomic, readonly, nullable) id defaultValue;
+
 @end
 
 NS_ASSUME_NONNULL_END