Prompt templates and your personal prompt library

If you use AI regularly, you probably type similar prompts again and again: explain this topic, review this code, draft this email. Each time you rewrite them from memory, you lose the improvements you made last time. Engineers solve this kind of problem by writing something once and reusing it. For prompts, that means templates.

In this tutorial you will build a personal prompt library: 5 to 10 tested templates, stored in one place, that you can fill in and use in under a minute. You need a free AI chat tool and somewhere to keep notes (Google Docs, Google Keep, Notion, a notes app or plain text files). It helps to have done the earlier lessons in this track, because your templates will reuse the six parts from *Anatomy of a good prompt*.

A template is a prompt with a fixed part and blanks. The fixed part holds everything that stays the same: the role, the rules, the output format and the lessons you learned the hard way. The blanks, called placeholders, hold what changes each time: the topic, the code, the email.

Think of a bank deposit slip or a college leave application format. Someone already decided what information is needed and in what order, so you only fill in your details.

You are a patient tutor for [SUBJECT].

Explain [TOPIC] to me.

About me: [MY LEVEL, e.g. 2nd-year B.Tech, I know Python basics]. I need this for [PURPOSE, e.g. an exam next week / an interview / a project].

Rules:
- Start with a one-line definition, then an everyday analogy.
- Give one worked example. For code, use [LANGUAGE].
- List 2 common mistakes or misconceptions.
- Under [WORD LIMIT] words.

End with 3 practice questions, easiest first, without answers.

What to expect: The rules and format were improved over many uses and never change. Only the bracketed parts change, so each use takes seconds and gives a consistent, tested shape of answer.

The best templates come from real use, not from imagination. When a chat finally gives you exactly what you wanted, usually after a few corrections, that is the moment to save it. The corrections you made ("shorter", "use a table", "don't assume I know React") are the valuable part, because they become rules in the template.

That last answer is exactly what I wanted. Turn this conversation into a reusable prompt template so I can get the same quality in one message next time.

Requirements:
- Include every correction I made during this chat as an explicit rule.
- Replace the parts that will change next time with placeholders in [CAPITALS], each with a short example, like [TOPIC, e.g. normalisation].
- Keep the output format I ended up with.
- Use at most 5 placeholders.
- Put pasted material (code, documents) last, inside tags.

Then list the placeholders and what goes in each.

What to expect: Check that the fixed part has no leftovers from this case (your specific topic, file name or company), and that your corrections really appear as rules.

A library you can't find things in is a library you don't use. Give each template a short header so that in three months you still know what it is for and whether it still works.

NAME: explain-topic
USE WHEN: learning a new topic for exams or interviews
INPUTS: SUBJECT, TOPIC, MY LEVEL, PURPOSE, LANGUAGE, WORD LIMIT
LAST TESTED: 2026-10 with Gemini and ChatGPT (free)
VERSION: 3 (v3: added 'common mistakes' section)

You are a patient tutor for [SUBJECT].
...rest of the template...

The header is for you, not the AI. Copy only the part below the header into the chat.

Group templates by the categories from this track: study, career, coding and work. Name them with a verb and an object (explain-topic, review-code, draft-reply, summarise-meeting) so the name tells you what it does.

matches:
  - trigger: ";review"
    replace: |
      You are a senior code reviewer. Review the code below for bugs, security issues and readability, in that order.
      For each issue give: line, problem, why it matters, a fixed version.
      Do not rewrite the whole file.

      <code>
      [PASTE CODE]
      </code>

After saving the file, typing ;review in any app replaces it with the template. Then paste your code over the placeholder.

Templates age. Models get updated, tools change their defaults and your needs grow. A template that gave great answers six months ago may now be too long, too cautious or formatted differently. Treat each template like a small piece of software: it has a version, and you re-test it when something changes.