PHP CodeSniffer supports the report format checkstyle which is supported by Code Review Assistant out of the box.

Example for Bamboo:

#!/bin/bash
php phpcs.phar --basepath=${bamboo.build.working.directory} \ 
    --report=checkstyle \
    --report-file=phpcodesniffer.xml .
cat phpcodesniffer.xml || echo "No PHP CodeSniffer report generated"
CODE