configuration.yaml

skills:
  - name: st2_opsdroid
    path: /opt/stackstorm/chatops/opsdroid-skills/st2
    config:
      prefix: '!'

st2_opsdroid.py

from opsdroid.skill import Skill
from opsdroid.matchers import match_regex

class StackStormSkill(Skill):
    def __init__(self, opsdroid, config):
        self._prefix = config['prefix']
        
    def match_prefix(self, func):
        return match_regex(self._prefix)(func)

    @match_prefix
    async def action_alias(self, message):
        pass