Introduction
A one-line request to an AI assistant usually returns something that looks finished and says little. The usual fix is to supply the information the first version left out.
This walkthrough follows one prompt through four revisions and a final correction. The teacher, the trip, and every output are invented for the exercise. The outputs are described and excerpted, and they don't come from any real product.
The Starting Point
Ms. Rivera teaches fifth grade. Her class is going to a science museum, and she needs every family to return a signed permission form. She types this into an AI assistant:
Write an email to parents about the field trip.
The assistant returns about 220 words. The email opens, "I am excited to announce an upcoming field trip that promises to be both educational and fun!" It contains placeholders in square brackets for the date, the place, and the cost. It closes by inviting parents to reach out with any questions.
Nothing in it is about her trip. The model had no facts, so it wrote the email that fits every field trip.
Walking Through the Revision
Step 1: Add the goal and the audience
Ms. Rivera asks herself what the email is for. She doesn't need parents to be excited. She needs the forms back on time. She also thinks about who's reading: busy parents and guardians, many of them on a phone.
She adds two sentences: "I teach fifth grade. The purpose is to get every signed permission form back by the deadline."
The new output mentions the form in the second sentence and ends with a request to return it. The model now knows what the email has to accomplish, and it arranged the email around that. The placeholders are still there, because the facts are still missing.
Step 2: Add the facts
She lists what a parent needs to know. The trip is on Thursday, May 14. The bus leaves school at 8:30 a.m. and returns by 2:45 p.m. The cost is $12 per student. Students need a packed lunch and a water bottle. The form and payment are due Thursday, May 7.
With these in the prompt, the placeholders disappear. The email is now about her trip. This is the pass that changes the output most, and it matches the developers' advice to include the information a model needs instead of assuming it has it (Google 2026a, "Add context").
The output has two new problems. It runs to nearly 250 words, and it includes the sentence "If you miss the deadline, just send the form when you can." She never said that. The model filled a gap with something agreeable.
Step 3: Add constraints
The invented sentence shows her which limits she left unstated. She adds four.
- Keep the email under 150 words.
- Use a warm, plain tone, with no exclamation marks.
- Don't promise that late forms will be accepted.
- Don't say the fee can be waived. Say that families can contact her privately about the cost.
The last two matter most. They concern promises that she, and not the assistant, would have to keep. The output comes back at 140 words, without the offer on late forms, and with a sentence inviting families to contact her about the cost.
It still reads like a form letter. The facts sit in one dense paragraph, and the deadline appears near the end.
Step 4: Add an example
Ms. Rivera has an email she sent in the fall about a book fair, which parents answered quickly. She pastes it in, and she says what it's for: "Here is an email I sent about a different event. Match its length, tone, and layout, and don't reuse its details."
Her old email has a subject line that includes the date, a first sentence that states the event, and a separate line that begins "What to do:". The new output picks up all three. The deadline moves into the subject line, and the action a parent must take gets its own line.
Describing that layout in words might still have been misread. Developers' guides recommend examples for this reason: Anthropic's calls them "one of the most reliable ways" to steer format, tone, and structure (Anthropic n.d., "Use examples effectively"). Her instruction not to reuse the details guards against the model copying the book fair's date or dollar amount into the new email.
Step 5: Read the output against the purpose and fix the remaining gap
She reads the result with one question in mind: could a parent act on this without asking her anything? The date, time, cost, and deadline are all there. The email says to return the form, and it doesn't say how.
That's a missing fact, and it's hers to supply. The output is otherwise right, so she replies in the conversation instead of rewriting the prompt: "Add that the form and payment go back in your child's take-home folder." The assistant adds one clause, and the email is ready for her to check against her own records and send.
She adds the same fact to her saved prompt.
Key Considerations
The common mistake in revising a prompt is to add words without adding information. A version that reads "Write a really excellent, professional, engaging, detailed email to parents about the field trip" is three times as long as the original and tells the model nothing new about the trip, the parents, or the purpose. The output would be the same generic email with more adjectives in it. Each of Ms. Rivera's passes added something the model couldn't have known.
The passes aren't equally important for every task. Here the facts did the most. For a task with a strict house style, the example might matter most.
OpenAI's guide lists the same kinds of content as the parts of a full prompt: instructions, examples, and context (OpenAI n.d.-a, "Message formatting with Markdown and XML"). Ms. Rivera added them one at a time, and with practice a person writes them all in the first draft.
A complete prompt doesn't check the output for her. The assistant could still have changed $12 to $21, so she compares every fact in the email with her own list before it goes out.
Summary
Ms. Rivera turned a one-line request into a prompt with a goal, the facts, constraints, and an example, then fixed one remaining gap in the conversation. Her final prompt follows.
I teach fifth grade. Write an email to my students' parents and guardians about our class trip to the science museum. The purpose is to get every signed permission form back by the deadline.
Facts: The trip is on Thursday, May 14. The bus leaves school at 8:30 a.m. and returns by 2:45 p.m. The cost is $12 per student. Students need a packed lunch and a water bottle. The signed form and payment are due Thursday, May 7, in the student's take-home folder.
Keep the email under 150 words. Use a warm, plain tone, with no exclamation marks. Don't promise that late forms will be accepted. Don't say the fee can be waived; say that families can contact me privately about the cost.
Here is an email I sent about a different event. Match its length, tone, and layout, and don't reuse its details.
Subject: Book fair visit on Friday, October 3 Dear families, our class will visit the school book fair on Friday, October 3. Students may bring up to $10 if you'd like them to choose a book. Nothing is required. What to do: if you're sending money, put it in a labeled envelope in the take-home folder. Thank you, Ms. Rivera
- Goal and audience. The first paragraph says who is writing, who will read the email, and what it has to accomplish.
- Context. The Facts paragraph supplies everything about the trip that the model couldn't know.
- Constraints. The third paragraph sets the length and tone, and names two promises the email must not make.
- Example. The past email shows the layout she wants, with a sentence saying what to match and what to leave behind.
References
- Anthropic. n.d. "Prompting Best Practices." Claude Developer Platform documentation. Accessed October 3, 2026.
- Google. 2026a. "Prompt Design Strategies." Gemini API documentation. Last updated September 17, 2026.
- OpenAI. n.d.-a. "Prompt Engineering." OpenAI API documentation. Accessed October 3, 2026.