All theaters are not the same and it’s especially important to understand this for Jump-Ins. If you’ve sung Violetta or Pamina in small regional theaters a Staatsoper is highly unlikely to hire you for a jump in, and you’ll probably mark yourself as unprofessional if you suggest it. For example if you’ve sung at Bielefeld, the Bayerische Staatsoper in München wouldn’t engage you as a jump in to sing these roles, but München Gärtnerplatz would. If you suggest the first an agent or KBB Leiter would consider you at best inexperienced, but the second would be realistic, depending on your qualifications.
This is similar to opera everywhere: an international level theater simply can’t afford to present an unknown quantity in a major role. Germany rates their theaters in a complex system which takes orchestra and chorus size, seating capacity and pay scale into account, and as bureaucratic as this may seem it does reflect the scale of the experience working and performing at these places. Halberstadt can be a wonderful place to learn and perform Tannhäuser, but doing it in Dresden or Hamburg is on a different scale. Agents have to understand this to have good relationships with theaters, and it’ll help your relationship with agents if you recognize this.