To access the inner city and its valuable information, you'll need to become a citizen. This involves a series of tasks and proving your worth to the First Citizen.

- The Courtyard: You'll start in the outer courtyard. Speak to the guards and citizens to understand their rules.
- Get a Day Pass: You can buy a day pass from the guard, or with high Speech, convince him to give you one.
- Complete Tasks for the First Citizen: The First Citizen will give you several tasks to prove your loyalty and competence. These often involve retrieving items, solving disputes, or performing repairs. Examples include:
- Retrieving the Servo-Arm: From the Gecko in Klamath.
- Fixing the Reactor: Requires a high Repair skill or finding a specific part.
- Resolving the Squatter Problem: In the nearby town of Modoc.
- Pass the Citizenship Test: After completing enough tasks, you'll be allowed to take a comprehensive test on Vault City's history and laws. Study the terminals in the courtyard or pay attention to dialogue.
Once you become a citizen, you'll gain full access to the inner city, including the Vault and its valuable records. This is a crucial step in your G.E.C.K. quest.