self.format = [{'fallback': '%s, %s' % (self.jiraIssueObj.fields.summary,
    self.link), 'pretext': 'Detail summary for %s' % self.jiraIssueObj,
    'title': self.jiraIssueObj.fields.summary, 'title_link': self.link,
    'text': self.jiraIssueObj.fields.description[0:self.maxSummary],
    'mrkdwn_in': ['text', 'pretext', 'fields']}]
Slack API - Attatchments from custom bot post as plain text