{"id":"cloudbuild-user-substitution-keys-underscore-prefix","text":"Cloud Build user-defined substitution keys must start with an underscore (`_`); `dynamicSubstitutions` must be `true` for bash parameter expansions with trigger-invoked builds.","truth_value":"IN","source":"entries/2026/03/11/cloudbuild-build-config.md","source_url":"","source_hash":"a29a3814882d14be","justifications":[],"dependents":[],"metadata":{},"explanation":{"steps":[{"node":"cloudbuild-user-substitution-keys-underscore-prefix","truth_value":"IN","reason":"premise"}]}}