Bluetooth GATT Descriptor Reference

Characteristic Extended Properties (0x2900)

org.bluetooth.descriptor.gatt.characteristic_extended_properties

If the Characteristic Extended Properties bit of the Characteristic Properties is set, then this descriptor exists. The Characteristic Extended Properties descriptor is a bit field defining Reliable Write and Writeable Auxiliaries are enabled for the Characteristic. This descriptor is readable without authentication and authorization being required.

Quick Summary

Payload length is 2 bytes. This page is generated from official GATT XML and presented as implementation-ready guidance.

At a Glance

Key reference details for BLE implementation, interoperability testing, and AI-assisted troubleshooting.

Property	Value
Name	Characteristic Extended Properties
UUID	0x2900
Type	org.bluetooth.descriptor.gatt.characteristic_extended_properties
XML Root	Descriptor
Source File	org.bluetooth.descriptor.gatt.characteristic_extended_properties.xml
Field Count	1

Field Specification

Parsed field definitions from the source XML value structure.

Field	Requirement	Format	Unit	Exponent	Notes
Properties	Mandatory	16bit	-	-	-

Bit Map

Bit-level enumerations extracted from the XML BitField definition.

Field	Bit	Size	Name	0 Means	1 Means
Properties	0	1	Bit	Reliable Write disabled	Reliable Write enabled
Properties	1	1	Bit	Writable Auxiliaries disabled	Writable Auxiliaries enabled

Byte Layout and Decode

Payload length is 2 bytes.

function decodePayload(dataView, offset = 0) {
  // Parse properties (16bit) according to Bluetooth format rules.
  return { properties };
}

Use Cases and Integration Notes

Descriptor Validation

Verify descriptor presence and format during integration and interoperability testing.

Client Configuration

Use descriptor semantics to configure notifications, indications, or presentation metadata.

Debug Diagnostics

Capture descriptor values alongside characteristic data for deeper BLE troubleshooting.

Implementation Checklist

Read descriptor metadata after characteristic discovery to confirm behavior contracts.
Respect descriptor read/write requirements before ATT operations.
Document descriptor values in exported BLE session logs for reproducibility.
Keep descriptor handling aligned with Bluetooth SIG format definitions.

FAQ

What is Characteristic Extended Properties in Bluetooth GATT?

Characteristic Extended Properties is defined as a Bluetooth GATT descriptor entry with type org.bluetooth.descriptor.gatt.characteristic_extended_properties and UUID 0x2900.

What UUID identifies Characteristic Extended Properties?

The UUID for Characteristic Extended Properties is 0x2900.

How should I parse Characteristic Extended Properties?