Custom GPT: Build a "Bank Teller Assistant" You Configure Once and Use Every Day

What This Builds

Instead of starting from a blank ChatGPT window every time and re-explaining your role, you'll build a Custom GPT that knows who you are, what bank products you work with, the scripts you use most often, and the regulations you need to reference. Every conversation starts from that foundation, like having a personal AI coworker who's already been briefed on your job.

Prerequisites

• ChatGPT Plus subscription ($20/month, required for Custom GPT creation)
• Comfortable with basic ChatGPT conversations (completed at least 5 conversations using the Level 3 guide)
• Product sheets and rate information from your branch (publicly available documents only)
• Time to build: 60–90 minutes initial setup; then 2–5 minutes per conversation

The Concept

A Custom GPT is like creating a specialized version of ChatGPT that has a permanent set of instructions about who it's talking to and what it knows. Instead of explaining "I'm a bank teller at a regional bank and I need help with Reg CC..." every single time, your Custom GPT already knows all of that. You just ask your question and get a useful answer immediately.

Think of it like the difference between hiring a temp employee (regular ChatGPT, which starts fresh every day) versus a colleague who's been on your team for a year (Custom GPT, which knows your context, your products, your common situations).

Build It Step by Step

Part 1: Access the Custom GPT Builder

1. Log in to ChatGPT at chat.openai.com with your Plus account
2. Click your profile icon in the upper-right corner
3. Select My GPTs from the dropdown menu
4. Click the + Create button (upper-right of the My GPTs page)
5. You'll land on the GPT Editor: a page split between a chat preview on the right and a configuration panel on the left

What you should see: Two panels. A "Create" tab with a configuration chat on the left, and a "Preview" panel on the right where you can test your GPT in real time.

Part 2: Write Your System Instructions

Click the Configure tab at the top of the left panel. You'll see several fields to fill in. This is where your GPT gets its personality, purpose, and knowledge.

Name: Bank Teller Assistant

Description: Helps bank tellers draft scripts, understand regulations, look up product information, and prepare for difficult customer conversations.

Instructions: Copy and paste the following, then customize the bracketed sections:

You are a Bank Teller Assistant for [your name], a bank teller with [X years] of experience at [type of bank, e.g. "a regional bank in the Southeast"].

Your job is to help me with:
1. Drafting customer-facing scripts and language (check hold explanations, fee dispute responses, cross-sell conversation starters)
2. Explaining banking regulations (Reg CC, Reg E, BSA/AML) in plain language with practical examples
3. Answering product knowledge questions based on the information I've uploaded
4. Helping me prepare for difficult customer conversations with scripts and anticipated objections
5. Generating study materials for certifications and internal compliance tests

Tone rules:
- Always write in plain language — no jargon unless I ask for it
- When writing customer-facing scripts, make them sound natural and human, not robotic
- When explaining regulations, lead with the practical implication before the rule
- Be direct and concise — I often ask questions between customers, so I need fast answers

Limitations:
- Do not give legal advice or make specific compliance decisions on my behalf
- If I ask about a specific customer's account, remind me not to share personal account data
- If I'm asking about my bank's specific internal procedures, note that you can only address general regulatory frameworks unless I've uploaded institution-specific policies

Conversation starters: Add these to give new conversations a quick launch:

• "Draft a check hold explanation for a customer"
• "Quiz me on BSA/AML for my compliance test"
• "Help me prepare for a fee dispute conversation"
• "What are our CD rates?" (will work after you upload product documents)

Part 3: Add Knowledge Documents

Still in the Configure tab, scroll down to the Knowledge section. Click Upload files and add:

• Your branch's product brochure (PDF or copy-paste as .txt)
• Current rate sheet
• Fee schedule

Important: Only upload public-facing documents: product brochures, rate sheets, and fee schedules that customers could get at the branch. Do not upload internal procedures, customer data, or confidential bank documents.

What you should see after uploading: Your files listed under the Knowledge section. The GPT will reference these documents when you ask product questions.

Part 4: Test and Refine

Click the Preview panel on the right and test your GPT with real questions:

1. "Draft a natural-sounding explanation of why a payroll check has a 2-day hold"
2. "What's the early withdrawal penalty on our 12-month CD?"
3. "Give me 3 conversation starters for a customer who just made their 10th large deposit"

Read the responses carefully. If they're too formal, add to your instructions: "Write all customer scripts in a warm, conversational tone." If the product information isn't accurate, check that your document uploaded correctly.

Troubleshooting: If the GPT says it doesn't know something from your uploaded documents, try asking more specifically: "According to my uploaded product sheets, what is..." This prompts it to search the knowledge base.

Part 5: Save and Access Your GPT

Click Save (upper-right). Choose Only me for visibility (this keeps it private). Your GPT will appear in My GPTs and also in the left sidebar of your ChatGPT conversations under a "My GPTs" section.

To use it: click it from the sidebar and start typing your question. No context-setting needed.

Real Example: Full Workflow

Setup: Your GPT has been configured with your product sheets and the instructions above.

Input: You have a customer waiting who deposited a $2,400 out-of-state personal check Monday and is now on Wednesday asking when the full amount will be available.

What you type (during break or before calling the customer back):

Customer deposited $2,400 out-of-state personal check on Monday. Today is Wednesday. When are funds available under Reg CC, and what's a clear way to tell them?

Output: "Under Reg CC, out-of-state personal checks typically have a 2-day hold, making funds available on Wednesday (the second business day after deposit Monday). Since today is Wednesday, the funds should be available now or by end of business today. You can tell the customer: 'The hold on your check has cleared. Your funds should be fully available in your account today. If you're checking online and still see a hold, it may take until the end of business day to fully update.'"

Time saved: 3–5 minutes of regulation lookup and script drafting, replaced by 30 seconds.

What to Do When It Breaks

• GPT gives vague or wrong product information → Check that your product document uploaded correctly; try re-uploading as plain text (.txt) instead of PDF
• GPT doesn't sound like it knows your role → Re-read your Instructions field; add more specific context ("I work at a community bank with 12 branches, serving a mix of seniors and working families")
• GPT gives overly cautious responses → Add to instructions: "I am a licensed bank employee. You can discuss regulatory frameworks directly without excessive caveats."
• Conversation starters disappear → Re-open Configure and re-add them; they occasionally reset

Variations

• Simpler version: Skip the knowledge upload and just use the instructions. You get the role-aware personality without product-specific answers
• Extended version: Add a "Scripts Library" section to your instructions with your 10 most-used scripts written out, so the GPT can pull from them directly

What to Do Next

• This week: Use your GPT for every script and regulation question that comes up. Note which answers need tweaking
• This month: Update product documents when rates change; add new scripts based on situations you encounter
• Advanced: Share the concept with your branch manager. A branch-wide version (with more thorough product docs) could be valuable for the whole team

Advanced guide for bank teller professionals. Custom GPTs require a ChatGPT Plus subscription. Never upload customer data or confidential internal documents.