Basic Policy

# This is effectively the name of the policy.
# It must be "policy".
package policy

import data.phylum.level
import future.keywords.contains
import future.keywords.if

# METADATA
# scope: rule
# schemas:
#   - data.issue: schema.issue
issue contains "risk level cannot exceed medium" if {
    data.issue.severity > level.MEDIUM
}

This is a basic policy using an issue rule to block any HIGH/CRITICAL issues.

The issue rule will contain the specified text when the if statement is true. OPA iterates through the job input data evaluating the expression against the severity and the level.