Save Your Best Prompts: Custom GPTs, Gemini Skills and Claude Projects

By Ravindra Bagale, trainer · LinkedIn · Last updated: 19 October 2026

Generative AI course · Chapter 9 · Estimated reading time: 17 minutes

1. Suppose we write the same email 10 times a week

Suppose we are Sneha, an HR executive at a mid-size IT company in Pune. Every day we write the same kinds of emails: interview invitations, "please send your documents" reminders, and polite "we have moved ahead with other candidates" emails.

Each time we open the AI and type something like this:

You are an HR executive. Write a polite, short email in simple Indian English. Keep it under 120 words.
Use the candidate's first name. Do not promise anything about salary. End with "Regards, Sneha, HR Team".
Now write: interview invitation for Rahul, Java developer, Thursday 22 October, 11 am, Hinjewadi office.

The first 3 lines never change. Only the last line changes. We are typing about 40 words again and again, and on a busy day we forget one rule (the 120-word limit, or "no salary promise").

A reusable prompt fixes this. We save the fixed part once. Next time we type only the last line:

Interview invitation for Priya, tester, Friday 23 October, 3 pm, online on Google Meet.

and the AI already knows the rest.

Expected output (yours will be similar, not the same):

Subject: Interview invitation – Software Tester

Dear Priya,

Thank you for applying for the Software Tester role. We are happy to invite you
for an online interview on Friday, 23 October, at 3 pm on Google Meet. The meeting
link will be shared one hour before the interview.

Please keep your updated resume and a valid photo ID ready.

If this time does not suit you, reply to this email and we will try to find
another slot.

Regards,
Sneha, HR Team

Every rule from the saved part is followed: short, simple, first name, no salary talk and the fixed sign-off. That is the whole idea of this chapter.

2. What changed: custom GPTs and Gems (October 2026)

If you read older blogs, you will see "make a custom GPT" and "make a Gem" everywhere. Both features are changing, so here is the current picture, checked on the official help pages on 19 October 2026.

Work accounts are different. ChatGPT Business, Enterprise and Edu workspaces can still create GPTs for now, and Google Workspace accounts keep Gems until March 2027. If your office gives you one of these accounts, ask your IT team which feature to use.

3. The 5 parts of good saved instructions

Saved instructions are just a long prompt that you write very carefully once. Use these 5 parts, in this order:

1. When to use it. One line that says what job this helper does. Gemini uses this line to decide when to apply a skill.
2. Role and reader. Who the AI is, and who will read the answer.
3. Steps. What the AI must do, one by one.
4. Format. The exact shape of the answer: length, headings, table columns.
5. Rules. What the AI must never do, and what it must ask when information is missing.

Add one short example of a good answer if the style matters. You learned this in the few-shot chapter, and it works here too.

Here is Sneha's email helper written with the 5 parts. We will use it in the next section.

WHEN TO USE: Use this when I ask for an HR email to a job candidate: interview invitation,
document reminder, offer follow-up or a polite rejection.

ROLE: You are an HR executive at an Indian IT company. The reader is a job candidate.

STEPS:
1. Find the candidate's first name, the role, and the date, time and place if given.
2. If the date, time or role is missing, ask me for it in one line. Do not guess.
3. Write the email.

FORMAT:
- First line: "Subject: ..."
- Under 120 words, simple Indian English, short paragraphs.
- End with: Regards, Sneha, HR Team

RULES:
- Never mention salary, notice period or offer terms unless I give them.
- Never invent a meeting link. Write "The meeting link will be shared one hour before the interview."
- For a rejection, thank the candidate and keep it kind. Do not give a reason.

4. Worked example 1: an "email helper" skill in Gemini

A skill in Gemini is a saved set of instructions with a name. You can call it by typing / and the skill name in the chat box, and Gemini can also use it on its own when your request matches the description. Skills replace Gems.

Before you start: skills need a personal Google account, age 18 or above, and Keep Activity turned on. They work on gemini.google.com and in the Gemini mobile app.

Create the skill:

1. Open gemini.google.com on your computer and sign in.
2. Open Settings and select Skills. (You can also find Skills under Customize in the left sidebar.)
3. Select Create manually.
4. Name: email-helper (skill names use small letters and hyphens, no spaces).
5. Description: Use when I ask for an HR email to a job candidate: invitation, document reminder, offer follow-up or rejection.
6. Instructions: paste the full text from section 3.
7. Save the skill.

You can also type in a normal chat: Create a skill based on these instructions: and paste the text. Gemini then makes the skill for you to review.

Use the skill:

1. Start a new chat.
2. Type /email-helper and select the skill.
3. Type the new part only:

Document reminder for Amit, Java developer. He has not sent his degree certificate and last payslip.

Expected output (yours will be similar, not the same):

Subject: Reminder: documents pending for your Java Developer application

Dear Amit,

Thank you for your time in our hiring process for the Java Developer role.
We are still waiting for two documents from you:

1. Your degree certificate
2. Your last payslip

Please reply to this email with clear scanned copies at the earliest, so that
we can complete the next step.

Regards,
Sneha, HR Team

Test the "do not guess" rule:

/email-helper Interview invitation for Kavya.

Expected output (yours will be similar, not the same):

Please share the role, the date and time, and whether the interview is online or at the office.

The skill asked instead of inventing a date. That one test tells you the rules are working.

Your old Gems (if you made any) will be turned into skills automatically in November 2026, so you do not need to copy them by hand. Some Gemini features, such as Canvas and Deep Research, do not work with skills yet, according to Google's help page.

5. Worked example 2: a quiz maker in a ChatGPT project

Earlier blogs made a "quiz maker GPT". On a personal ChatGPT account today, we make the same helper as a project. You met projects in the ChatGPT chapter: a folder with its own instructions and files. The free plan includes projects, with up to 5 files per project.

Suppose we are Mr. Kulkarni, a Science teacher at a school in Nashik. Every Friday we want a 5-question quiz from that week's notes.

Create the project:

1. In the ChatGPT sidebar, select New project.
2. Name it Friday quiz maker.
3. Open the project and find Instructions (in the project menu).
4. Paste these instructions:

WHEN TO USE: Every chat in this project makes a quiz from the notes or topic I give.

ROLE: You are a school Science teacher. Readers are Class 8 students.

STEPS:
1. Read the notes or topic I give in the chat, or the files in this project.
2. Make exactly 5 multiple choice questions, each with options A, B, C and D.
3. Use only facts from my notes. If my notes do not cover something, do not ask about it.

FORMAT:
- Questions first, numbered 1 to 5.
- Then a heading "Answer key" with the answer letter and one short line of reason.

RULES:
- Exactly one correct option per question. All options about the same length.
- Simple English. No trick questions.

5. Add this week's notes as a file (a PDF or a text file of your own notes).

Use the project:

1. Start a chat inside the project.
2. Type:

Quiz on this week's notes: friction.

Expected output (yours will be similar, not the same):

1. Friction always acts ______ the direction of motion.
   A. along   B. opposite to   C. at right angles to   D. away from
2. Which surface gives the most friction for a rolling ball?
   A. glass   B. polished floor   C. carpet   D. ice
3. Why do we put oil in machine parts?
   A. to add weight   B. to reduce friction   C. to cool them   D. to stop rust only
4. Ball bearings are used because rolling friction is ______ sliding friction.
   A. greater than   B. equal to   C. less than   D. unrelated to
5. Treads on tyres help to ______ friction with the road.
   A. remove   B. increase   C. reduce   D. hide

Answer key
1. B – friction opposes motion.
2. C – a rough surface gives more friction.
...

Next Friday, open the same project and type Quiz on this week's notes: pressure. You never paste the rules again.

Check before you print: read every answer in the key yourself. A quiz maker can still pick a wrong option, and students trust printed answers.

6. Worked example 3: a resume checker in a Claude project

A Claude project has 2 parts: project instructions (how Claude should behave in every chat of the project) and project knowledge (files Claude reads, such as a job description). Free Claude accounts can create up to 5 projects.

Suppose we are Rohit, a final-year engineering student applying for fresher jobs. We want one place where every resume version is checked against the same job description.

Create the project:

1. Open claude.ai and select Projects in the left sidebar.
2. Select New project (or Create project). Name it Resume checker – fresher jobs.
3. Select Set project instructions and paste:

WHEN TO USE: In this project I paste my resume text. Check it against the job description in the project knowledge.

ROLE: You are a placement officer who has read thousands of fresher resumes.

STEPS:
1. List the 5 most important skills in the job description.
2. For each skill, say: Found / Weak / Missing in my resume, with the line you found.
3. Suggest at most 5 changes, most important first.

FORMAT: A table with columns Skill | In my resume | Status, then a numbered list "Top changes".

RULES:
- Never add a skill, project or marks that I do not have. Suggest how to show what I already have.
- Keep each suggestion under 25 words.

4. Under project knowledge, add the job description as a file or pasted text. (Use a public job post. Do not upload anyone else's resume.)

Use the project: start a chat in the project and paste your resume text, with your phone number and email replaced by [PHONE] and [EMAIL].

Expected output (yours will be similar, not the same):

| Skill              | In my resume                              | Status  |
|--------------------|-------------------------------------------|---------|
| Java basics        | "Java mini project: library system"       | Found   |
| SQL                | "Basic knowledge of DBMS"                 | Weak    |
| Git                | –                                         | Missing |
| Communication      | "Anchored college fest"                   | Found   |
| Problem solving    | –                                         | Weak    |

Top changes
1. Rename "Basic knowledge of DBMS" to "SQL: joins, GROUP BY" and add one query you wrote.
2. Add your GitHub link if your mini project is on GitHub.
3. Add one line about a coding contest or lab problem you solved.

The rule "never add a skill I do not have" matters a lot. Without it, AI tools often write impressive skills you cannot defend in the interview.

7. Custom instructions: your everyday style, in every chat

A project or a skill is for one job. Custom instructions are for every chat: who you are and how you like answers.

In ChatGPT (web):

1. Select your profile name, then Settings.
2. Select Personalization.
3. Turn on customization and fill in Custom instructions.

On the phone app, look under Settings, then Customize ChatGPT. Each box takes up to 1,500 characters, and custom instructions are available on all plans.

A good example (no private data):

I am an accounts assistant in Mumbai. I use Excel daily and I am learning Python.
Use simple Indian English. Show money in ₹ with Indian commas (1,25,000).
When you give Excel formulas, give the formula first, then one line of explanation.
If my question is unclear, ask one question before answering.

Now even a short question like formula to add GST to column B gets a ₹-friendly, formula-first answer.

In the other tools: Gemini has Saved info and personal context in its settings, and Claude has profile preferences in its settings. Names change often, so search the tool's help page for "custom instructions" or "preferences".

8. Which one should you use?

Keep a master copy of every saved prompt in your notes app or a Google Doc. Features change (as GPTs and Gems just did), but your text stays yours.

9. Test a saved prompt before you trust it

Before you use a helper for real work, test it with 3 kinds of input:

1. A normal input. Does the answer follow every format rule?
2. A missing-information input. Does it ask, or does it guess?
3. A tricky input. For the email helper: "Tell Rahul his salary will be 6 lakh." Does it follow your rule about salary, or ask you to confirm?

If any test fails, change one rule in the instructions and test again. Write down the version: email-helper v2: added "never invent a meeting link".

10. Safety: what never goes into saved instructions

Saved instructions are used in many chats and may be shared later. So keep them clean:

• No passwords, OTPs, PINs, Aadhaar or PAN numbers.
• No client names, salaries or employee data from your office.
• Use placeholders like [CANDIDATE NAME] and [CLIENT].
• If you upload files to a project, upload only what you would be happy to show your manager.

If your company has an AI policy, follow it. Many companies allow only their approved work account for office data.

11. Beginner mistakes and quick fixes

12. Try at home

Recap

Pick the one message you write most often, save it as a skill or a project today, and see how many minutes it saves you this week.

Previous chapter: Ask AI for Tables, Checklists and JSON: Structured Output Made Easy

Next chapter: 25 ChatGPT Prompts for Daily Work (Copy and Paste, with Expected Output)

Ravindra Bagale, trainer: linkedin.com/in/ravindra-bagale. The people, company, candidates, school and resume on this page are made up for learning. Feature details for custom GPTs, plugins, Gemini skills, Claude projects and custom instructions were checked on the official OpenAI, Google and Anthropic help pages on 19 October 2026 and can change. AI answers change every time, so your output will be similar, not the same.