chatgpt-custom-instructions-and-memory
Module 3 · Lesson 2 of 3 · Course Lesson 10 of 26
Custom Instructions and Memory
Learn what you write deliberately, what ChatGPT may remember from conversations and how to review, correct, disable or remove personalisation without confusing one control for another.
- Beginner
- About 18 minutes
- Personalisation audit
- 4-question check
Learning Objectives
What you will learn
By the end of this lesson, you will be able to:
- Explain the difference between Custom Instructions, saved memories and chat-history reference.
- Choose the correct scope for global, Project-specific and one-chat guidance.
- Add or edit safe Custom Instructions.
- Ask what ChatGPT remembers and review available Memory controls.
- Use Temporary Chat when you do not want memory used or created.
- Remove unwanted personalisation from every relevant source.
Personalisation Map
Five controls with different jobs
These features can all shape a response, but they do not store or apply information in the same way.
Custom Instructions
Direct guidance you write for ChatGPT to consider broadly, such as preferred language, tone and response format.
Saved memories
Details ChatGPT keeps for future conversations, including items you explicitly ask it to remember.
Chat-history reference
Relevant information drawn from past conversations. It does not retain every detail and can change over time.
Project instructions
Guidance limited to one Project. It overrides global Custom Instructions inside that Project.
Temporary Chat
A conversation that does not appear in history or use or create personalisation memories. Enabled Custom Instructions can still apply.
Side-by-Side
Put information in the right place
| Feature | Who decides the content? | Good example | How to manage it |
|---|---|---|---|
| Custom Instructions | You write and edit explicit guidance. | “Use New Zealand English and explain unfamiliar terms.” | Settings → Personalization → Custom Instructions or Customize ChatGPT. |
| Saved memory | You can ask ChatGPT to remember; ChatGPT may also save useful details when enabled. | “Remember that I am learning website accessibility.” | Ask what it remembers, ask it to forget, or manage Memory in settings. |
| Reference chat history | ChatGPT selects relevant context from prior chats when enabled. | Recalling that a continuing website uses the ITIAN colour palette. | Turn the setting on or off, and delete or archive source chats where appropriate. |
| Project instructions | You set instructions for one Project. | “For this course, every page must include lesson navigation.” | Open the Project menu → Project settings. |
| Current prompt | You state the requirement for this task. | “For this answer only, give me a two-sentence summary.” | Edit or follow up in the current conversation. |
Set Up Custom Instructions
Add stable preferences carefully
Custom Instructions are available across current ChatGPT plans on web, desktop and mobile. Long-form fields currently have a 1,500-character limit.
Web and desktop
- Open your profile and Settings.
- Select Personalization.
- Open Custom Instructions.
- Turn on Enable customization.
- Add concise instructions and save.
- Test them with a new prompt.
iOS and Android
- Open Settings.
- Select Customize ChatGPT.
- Turn on Enable customization.
- Add the instructions you want applied.
- Test with a simple new conversation.
What belongs there
- Stable goals and general context.
- Preferred language and tone.
- Useful formats and explanation level.
- Verification and permission rules.
- No passwords, secrets or unnecessary sensitive details.
Keep global instructions genuinely global
If a rule applies to only one course, client or project, put it in that Project rather than forcing it into every ChatGPT conversation.
Draft and Copy
Prepare two concise instruction blocks
Adapt the profile you created in the previous lesson. This drafting tool does not save your text in browser storage.
Review Memory
Ask, inspect and correct
Memory interfaces vary by plan and rollout. Look under Settings → Personalization → Memory, and use direct questions when you need clarity.
Turning Memory off does not delete saved information
Review and delete unwanted memories separately. Deleting a chat also does not automatically remove a saved memory that came from it.
Complete Removal
Delete the detail from every source
If you want ChatGPT to stop using particular information, check every place where that information may still exist.
1. Memory
Delete or correct the saved memory or memory-summary entry in Personalization settings.
2. Chats
Delete the conversations where the information was shared or repeated. Archived chats can still be a source.
3. Custom Instructions
Edit or remove the instruction, then check that enabled settings reflect your choice.
4. Files
Delete relevant saved files from Library or Project sources where the detail appears.
5. Connected apps
Disconnect or manage external sources that may still contain the information.
6. Test again
Ask what ChatGPT remembers and review settings after changes have had time to apply.
“Don’t mention this again” is not the same as deletion
It can reduce unwanted references, but current official guidance says full deletion requires removing the information from every source where it appears.
Practical Activity
Complete a personalisation audit
Use only information you are comfortable keeping in ChatGPT. Progress is saved in this browser.
Knowledge Check
Check your understanding
Select one answer for each question.
Finish the Lesson
Record your progress
Official References
Learn more from OpenAI
This lesson was checked against current official OpenAI Help Centre guidance.