With all the new AI models in Microsoft Copilot along with the first party agents that serve spefici functions, it can be confusing to know which tool to use for the right task. Microsoft have two specific agents within the Microsoft 365 Copilot domain Researcher and Agent designed to carry outr specific functions. We also now have GPT-5 (now also baked into Copilot) which brings the new “smart” mode, allowing it to switvch between languiage models based on the task at hand.
In this blog, I aim to break down the three tiers of Copilot capability— GPT-5 Chat, GPT-5 Reasoning (also known as Smart mode), and Researcher and to look at the differences, similarities and what is best for what!
GPT-5 Chat: Fast, Friendly, and to the Point
Best for:
- General Chat and Quick Q&A
- Content Summarisation
- Creative brainstorming
How it thinks:
Chat mode is is your rapid-fire assistant. It delivers supoer quick responses to youur questions without deep analysis. This is ideal for when you need an answer or exmplanation, clarity on something and anything not requiring deep thinking, reasoning or complexity.
Example prompt:
“Write a short social post abou the latest updates to [product].”
When to use it:
When you want brevity, speed, and a touch of flair. Think elevator pitches, tweet-length summaries, or light creative riffs.
GPT-5 Reasoning: Structured Thinking for Strategic Tasks
Best for:
- Logical analysis
- Problem-solving
- Multi-step planning such as building a travel itinery, project plan or talk track
How it thinks:
This mode (which GPT-5 will switch too automatically if needed), rolls up its sleeves and gets analytical. It’s designed for tasks that require synthesis, deep exploratory analysis, structured responses and a more strategic (deep thinking) response.
Example prompt:
“Let’s walk through this problem together: I need to launch a new product with a limited budget and a small team to appeal to an already crowded market. What’s the best strategy?”
Use it when:
You’re building timelines, weighing trade-offs, or need a coherent plan that holds up under scrutiny.
Copilot Researcher Agent: Deep Dives and Source-Backed Intelligence
Best for:
- Comprehensive research and reports
- Source comparison and opinioning
- Insight generation
How it thinks:
Researcher mode is a custom build agent from Microsoft specifically designed to work in a recursive, self evaluation and exhaustive approach. It pulls from multiple sources which it compares and contrats against one-another, compares methodologies, and identifies gaps. This is design for for thought leadership, academic-style or research style analysis, or strategic decision-making with different view points.
Example prompt:
“Find and summarise studies on the effects of remote work on productivity. Compare methodologies and results, looking at pro’s cons, impact on society, well-being, productivity and trends across different EU regions.”
Use it when:
You need more than just an answer. You want to combine different view, present the otput in a particular way and when you need comprehenisive evidence, nuance, and a narrative that stands up to boardroom or peer review.
Which One When?
There is no definitiave answer to this, but based on my usage and infomration I have read in the field, guidance from OpenAI, Microsoft and others, this table provides a guide to which mode would work best in the scenaios below
| Task Type | Use GPT-5 Chat | Use GPT-5 Reasoning | Use Researcher |
|---|---|---|---|
| Write a quick summary | ✅ | ||
| Build a strategic roadmap | ✅ | ||
| Compare academic studies | ✅ | ||
| Brainstorm creative ideas | ✅ | ||
| Solve a complex problem | ✅ | ||
| Generate source-backed insights | ✅ |
AI isn’t a one-size-fits-all and not all use cases are the same. As AI models contine to become more context aware and with the ability to switch modes, there are still many times where knowing where to take your problem to is key – just like you know to talk to a specialist consultant vs a generalise at times.
Currently, to get the best from these AI models, the best result often lies in knowing when to switch gears—from conversational to analytical to research-grade depth. Whether you’re a CTO shaping strategy or a content creator chasing clarity, the right mode turns AI from assistant to partner to mentor.
Would you like this adapted into a SharePoint-friendly format or paired with a branded visual? I can also tailor it for internal enablement or customer-facing use.
