Using services inside a schema transformation in Effect Typescript library

const ZoneFromURL = S.transformOrFail(
  S.String,
  ComputeZone,
  {
    strict: true,
    decode: (zoneURL) => S.decodeUnknown(ComputeZone)(zoneURL.split("/").pop()).pipe(
      Effect.mapError((e) => e.issue)
    ),
    encode: (zone) => Effect.gen(function*() {
      const projectId = yield* ProjectId // <- how can I make this work? I want `ProjectId` to be a requirement of the schema. Is this possible?
      return `https://www.googleapis.com/compute/v1/projects/${projectId}/zones/${zone}`
    })
  }
)