An example of dynamically adding a trigger step during a running Buildkite build

step.sh

#!/bin/bash

set -euo pipefail

cat << YML | buildkite-agent pipeline upload
steps:
  - trigger: "other-pipeline"
    async: true
    build:
      message: "${BUILDKITE_MESSAGE}"
      commit: "${BUILDKITE_COMMIT}"
      branch: "${BUILDKITE_BRANCH}"
YML