Build Your Own AI Assistant: Custom GPTs, Gemini Gems and Claude Projects

What you need before you start

• A clear job: “Reply to customer emails in our style” is better than “business helper”.
• Standing instructions: role, tone, format, and what it must never do.
• Reference files: FAQs, price list, style guide, examples of good output.

ChatGPT: Custom GPTs

1. 1

   Open the GPT builder

   In ChatGPT, go to GPTs (Explore GPTs) and choose Create. Creating GPTs requires a plan that includes it.

2. 2

   Configure

   Give it a name, a short description, and detailed instructions. Add conversation starters that show users what to ask.

3. 3

   Add knowledge

   Upload your reference files so answers use your information.

4. 4

   Choose capabilities

   Turn on web search, image generation or data analysis only if the job needs them.

5. 5

   Test and share

   Use the preview panel to test real questions, then save it as private, link-only, or public.

Gemini: Gems

1. 1

   Open Gems

   In Gemini, open the Gem manager and choose to create a new Gem.

2. 2

   Write instructions

   Describe the role, task and format. Gemini can help rewrite your instructions to be clearer.

3. 3

   Add files

   Attach reference files where supported so the Gem can use them.

4. 4

   Save and use

   Your Gem appears in the sidebar; open it whenever you need that assistant.

Claude: Projects

1. 1

   Create a project

   In Claude, create a new Project for the ongoing work.

2. 2

   Set project instructions

   Add instructions that apply to every chat inside the project.

3. 3

   Add knowledge

   Upload documents to the project knowledge so every chat can reference them.

4. 4

   Chat inside it

   Start chats from within the project; each one starts with your instructions and files.

Writing instructions that work

ROLE: You are the customer-support assistant for [business].
GOAL: Answer customer questions using only the attached FAQ and price list.
STYLE: Friendly, short paragraphs, maximum 120 words, reply in the customer’s language.
RULES: If the answer is not in the files, say you will pass the question to a human. Never promise refunds or discounts. Never invent prices.
FORMAT: Greeting, answer, one helpful next step.