I co-facilitated a session recently introducing Copilot in which we discussed writing better prompts, along with the value of sticking to a framework such as the GCES framework — Goal, Context, Expectations, Source. It’s a structure I use constantly. It’s simple, it’s quick, and it gets you usable output in a hurry.

But a few people in the room asked the question I always hope someone asks: “Is this the only way to do it?”

No. It’s the way I default to for everyday work. There’s another one I reach for when the stakes shift.
I think it’s worth knowing both, because the choice between them is actually a choice about what you’re trying to make Copilot do.

Start with the principle, not the framework

Before either framework, the rule that matters most is this: Copilot (or other LLMs) works best when you give it clear instructions, the way you would to a colleague. Not a clever incantation. Not a secret keyword. A clear, useful brief.
The frameworks are just scaffolding around that idea. They’re checklists that stop you from leaving out the bits that matter.
And prompting itself is a loop, not a single shot:

Ask → Review → Refine.

Treat it as a conversation, not a one-off task. Whichever framework you use, the first response is rarely the final one.

GCES: your everyday structure

GCES is the one I teach first because it covers most of what most people do with Copilot most of the time.

• Goal — what do you want?
• Context — who is it for, and why does it matter?
• Expectations — format, tone, length.
• Source — what information should it use?

Four parts. Easy to remember. Forces you to stop and answer the basic questions before you hit enter.

Here’s an example showing the difference it makes:

Basic prompt: “Summarise this report.”

Structured prompt: “Summarise this report for a senior leadership audience (Context). Focus on key risks and decisions (Goal). Present as 5 concise bullet points (Expectations). Use only the attached document (Source).”

The basic version will give you something. The structured one gives you something you can actually use.

Layered on top of GCES, there are a few habits that quietly do a lot of the work:

• Be specific. Avoid vague requests.
• Add context. Tell Copilot who and why.
• Control the output. Format, tone, structure.
• Break it down. Ask in steps, not one big question.

And the smallest upgrade trick of all: drop “Act as a [role]…” into the front of any prompt. It is amazing how much that one phrase shifts the response.

CO-STAR: when you need more than a fast answer

CO-STAR is a six-part framework developed by GovTech Singapore for prompt engineering across the public sector. The six parts are:

• Context — background and scenario.
• Objective — the specific task.
• Style — the writing style or persona.
• Tone — mood and sentiment.
• Audience — who will read it.
• Response — output format.

What I find interesting is what CO-STAR does differently from GCES. It splits things that GCES bundles together. Audience gets pulled out as its own step. Style and tone become separate decisions rather than a single “expectations” line. And Response nails down the format explicitly.

You can feel the difference when you use it. GCES is asking “what do you want this to say?” CO-STAR is asking “what do you want this to say, and how should it sound, and to whom?”

So when do I use which?

This is the question I find more useful than “which is better?” 
Why? Because they aren’t competing. They’re answering different problems.

I reach for GCES when:

• I’m doing quick Copilot tasks
• The work is internal — emails, summaries, analysis, meeting prep
• I want something usable, fast

I reach for CO-STAR when:

• I’m writing for stakeholders or a public audience
• Tone and messaging really matter
• I need something polished or publishable

Or, if you want it in a single line: GCES is for getting the right answer. CO-STAR is for getting the right answer and the right voice.

The other way I think about it: GCES is what I use when I’m being efficient. CO-STAR is what I use when I’m being deliberate.

The bit I want change managers and trainers to hear

There’s a temptation, when you’re rolling Copilot out across an organisation, to land on a single framework and standardise. One framework. One handout. One way of doing it.

I understand the impulse as consistency is comforting, and people genuinely do better when they have a structure rather than no structure. But I think we underestimate how quickly people outgrow the starter framework once they start using Copilot for real work. A few weeks in, the everyday prompts get easy. The harder asks start showing up. The polished communications, the stakeholder messages, the things where tone matters as much as content.

If we only ever teach the simple framework, we leave people stuck at the level of the simple framework. And then we wonder why adoption plateaus.

Teaching both (and being explicit about when to use which) gives people somewhere to grow into. It signals that prompting is a craft, not a trick. And it respects that the people we’re training will, very quickly, be doing more sophisticated things than the worksheet anticipated.

Teach the framework. Then teach the framework you graduate to.

What I’m taking away from this

A few things I’m carrying forward, both into my own work and into the way I support teams through Copilot adoption:

• Start with GCES. It is the right place to begin. Don’t over-complicate the on-ramp.
• Introduce CO-STAR as the next level. Frame it as “when you’re ready for more control.” Don’t position the two as competitors.
• Make the when explicit. People don’t struggle to learn frameworks. They struggle to know which one fits the moment in front of them.
• Keep coming back to the principle. Clear instructions. Like you would give a colleague. Everything else is scaffolding.

I’ll keep playing with both, and I’ll keep watching for the moment people make the jump from GCES to CO-STAR on their own – because that, to me, is the moment Copilot stops being a tool they use and starts being a tool they think with.

Want to learn more? Below are some links to explore this further.

• Microsoft — Optimise your prompts for Copilot: learn.microsoft.com/copilot-studio/guidance/optimize-prompts-overview
• GovTech Singapore — CO-STAR prompt framework: tech.gov.sg/technews/mastering-the-art-of-prompt-engineering-with-empower