Each agent that exports a schema identifies itself using a package name. The package provides a unique namespace for the classes in the agent's schema that prevent collisions with identically named classes in other agents' schemata.

Package names are in "reverse domain name" form with levels of hierarchy separated by periods. For example, the Qpid messaging broker uses package "org.apache.qpid.broker" and the Access Control List plugin for the broker uses package "org.apache.qpid.acl". In general, the package name should be the reverse of the internet domain name assigned to the organization that owns the agent software followed by identifiers to uniquely identify the agent.

The XML document for a package's schema uses an enclosing <schema> tag. For example:

<schema package="org.apache.qpid.broker">

</schema>

Object classes define types for manageable objects. The agent may create and destroy objects which are instances of object classes in the schema. An object class is defined in the XML document using the <class> tag. An object class is composed of properties, statistics, and methods.

  <class name="Exchange">
    <property name="vhostRef"   type="objId" references="Vhost" access="RC" index="y" parentRef="y"/>
    <property name="name"       type="sstr"  access="RC" index="y"/>
    <property name="type"       type="sstr"  access="RO"/>
    <property name="durable"    type="bool"  access="RC"/>
    <property name="arguments"  type="map"   access="RO" desc="Arguments supplied in exchange.declare"/>

    <statistic name="producerCount" type="hilo32"  desc="Current producers on exchange"/>
    <statistic name="bindingCount"  type="hilo32"  desc="Current bindings"/>
    <statistic name="msgReceives"   type="count64" desc="Total messages received"/>
    <statistic name="msgDrops"      type="count64" desc="Total messages dropped (no matching key)"/>
    <statistic name="msgRoutes"     type="count64" desc="Total routed messages"/>
    <statistic name="byteReceives"  type="count64" desc="Total bytes received"/>
    <statistic name="byteDrops"     type="count64" desc="Total bytes dropped (no matching key)"/>
    <statistic name="byteRoutes"    type="count64" desc="Total routed bytes"/>
  </class>

<property> and <statistic> tags must be placed within <schema> and </schema> tags.

Properties, statistics, and methods are the building blocks of an object class. Properties and statistics are both object attributes, though they are treated differently. If an object attribute is defining, seldom or never changes, or is large in size, it should be defined as a property. If an attribute is rapidly changing or is used to instrument the object (counters, etc.), it should be defined as a statistic.

The XML syntax for <property> and <statistic> have the following XML-attributes:

<method> tags must be placed within <schema> and </schema> tags.

A method is an invokable function to be performed on instances of the object class (i.e. a Remote Procedure Call). A <method> tag has a name, an optional description, and encloses zero or more arguments. Method arguments are defined by the <arg> tag and have a name, a type, a direction, and an optional description. The argument direction can be "I", "O", or "IO" indicating input, output, and input/output respectively. An example:

   <method name="echo" desc="Request a response to test the path to the management broker">
     <arg name="sequence" dir="IO" type="uint32"/>
     <arg name="body"     dir="IO" type="lstr"/>
   </method>

Object attributes, method arguments, and event arguments have data types. The data types are based on the rich data typing system provided by the AMQP messaging protocol. The following table describes the data types available for QMF:

In the XML schema definition, types go by different names and there are a number of special cases. This is because the XML schema is used in code-generation for the agent API. It provides options that control what kind of accessors are generated for attributes of different types. The following table enumerates the types available in the XML format, which QMF types they map to, and other special handling that occurs.