XML is language with tree structure. Root is definition of model:

<?xml version="1.0" encoding="UTF-8"?>
<actr>
    <model name="SimplePoJACTRAgent" >

For defining modul it is required full name of class that implements interface IModule. If modul is parametrized, it has to implements IParametrized. If you are interesting into implementing new modules you will find usefull some preimplemented abstract classes (i.e AbstractPerceptualModule).

<modules>
  <module class="org.jactr.core.module.declarative.six.DefaultDeclarativeModule6">
    <parameters>
      <parameter name="ActivationNoise" value="0.1"/>
      ...
    </parameters>
  </module>
  ...
</modules>

Declarative memory has to have defined all chunk types that is used by jACT-R. Every chunk has to have defined name, his slots and his implicit values. Then model can use chunks of defined chunk type. Some chunk types are defined automaticly by modules or buffers by special chunk factories (i.e. auralChunkType in AuralChunkFactory)

<declarative-memory>
  <chunk-type name="count-order" >
    <slot name="first" equals="nil"/>
    <slot name="second" equals="nil"/>
  </chunk-type>
    ...
  <chunk name="a" type="count-order" >
    <slot name="first" equals="0.0"/>
    <slot name="second" equals="1.0"/>
  </chunk>
    ...
</declarative-memory>

Procedural memory contains all production rules. Tag condition define condition part, which is something like template for matching in first phase of cognitive cycle. Tag match says which chunk has to be in which buffer to enables production rule.

Tag action defines executive part of production. Currently supported tags are:

<procedural-memory>
  <production name="pogamutTestJump">
    <condition>
      <match buffer="goal" type="pogamutGoalChunk">
        <slot name="waitFor" equals="jumpOnRocket"/>
      </match>
      <match buffer="defaultAuralActivationBuffer" type="auralChunk">
        <slot name="class" equals="XWeapons.RocketLauncher"/>
      </match>
    </condition>
    <action>
      <modify buffer="goal">
        <slot name="waitFor" equals="somethingElse"/>
      </modify>
      <add buffer="movementCommandBuffer" type="commandChunk">
        <slot name="command" equals="jump"/>
      </add>
      <output>"Jumping !!"</output>
    </action>
  </production>
  ...
<procedural-memory>

Last section define all buffers, with which model can work. Buffer has to implement interface IActivationBuffer and if it is parametrized interface IParametrized.

<buffer name="defaultAuralActivationBuffer" >
  <parameters>
  ...
  </parameters>
</buffer>