Mpromp2 — the AI Prompt GeneratorSkills Library / ChatGPT
ChatGPT Custom Instructions, Projects & GPTs
ChatGPT's equivalent of a skills layer is spread across three mechanisms: Custom Instructions (who you are and how it should answer, applied everywhere), Projects (a workspace with its own files and project-level instructions), and custom GPTs (a packaged assistant with its own instructions, knowledge files, and actions). This page explains which to use for what, and gives you instruction sets to copy.
How it works
Custom Instructions hold two things: facts about you and your work, and how ChatGPT should respond - format, tone, and rules. Projects are folders for ongoing work: chats, uploaded files, and project instructions that override general behavior inside that project - the closest ChatGPT analogue to a project memory file. Custom GPTs go furthest: a named assistant with a system instruction set, uploaded knowledge, and optional API actions, shareable by link. The craft in all three is the same as in a SKILL.md: write the instruction set as a procedure with standards, not as a personality sketch.
Setup, step by step
- Decide the scope: everywhere (Custom Instructions), one body of work (Project), or a reusable specialist (GPT)
- Write the instruction set as: role, standing rules, output formats, and what to never do
- Add files the assistant should treat as reference - and say in the instructions how they rank
- Test with three real tasks, including one edge case, before relying on it
- Revise from failures: every wrong output is a missing line in the instructions
Copy-ready starter file
Field notes
The most common failure is writing instructions as traits ('be helpful, be concise') instead of procedures ('lead with the answer; mark unverified facts'). Procedures are followable; traits are decoration - the same rule that governs good SKILL.md files.
Keep going
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