Copilot shelf

Agent Instruction Block Design Guide

Write agent instructions that behave. The fiftieth user gets the same result you did on day one.

One-time. Updates included.

Extracted from an open-source Copilot Chat agent library, now 82 published.

“Battle-tested in production environments.”

That is how Jared Spataro, Microsoft’s CMO for AI at Work, described my free, open-source Copilot prompt library in the AI at Work newsletter, February 2026. He was citing that free repo, not this product. This is the paid work from the same practice, held to the same standard.

The situation

Anyone can paste an instruction block into Copilot Studio. What separates agents that get used from agents abandoned after a week is the design.

Most instruction blocks fail not because they are wrong about what the agent should do, but because they are silent about what it should never do. They are vague about edge cases. They say "be helpful" instead of naming the exact action that would be unhelpful.

What this is

Twelve design patterns extracted from building real Copilot Chat agents, open source and in production, a library that now runs to 82 published agents. Each pattern includes a before and after instruction block and a plain explanation of which failure mode it prevents.

What is inside

12 design patterns with before and after examples
The failure mode each pattern prevents
A review checklist for somebody else's instruction block

Who it is for

Anyone writing instruction blocks for Copilot Studio or Copilot Chat agents
Reviewers who have to judge whether somebody else's agent is safe to ship

Who it is not for

People who want finished agents rather than the patterns behind them. That is the Agent Pack.

Questions people actually ask

Does this work if we are on E3 rather than E5?

Yes. M365 Copilot is a paid add-on that sits on top of a qualifying M365 licence, so the licence tier underneath changes what data Copilot can reach, not whether this material applies. Where an E5-only control is the cleanest answer to something, the material says so and gives the E3 route as well.

Is this current for the June 2026 GA wave?

Yes. Cowork went generally available worldwide on 16 June 2026 and brought a metered layer billed in Copilot Credits at $0.01 each. Everything here is written against that change rather than around it. Updates are included, so when the next wave lands you get the revision at no extra cost.

What if we have not enabled Cowork yet?

That is the common case and it is fine. The metered layer is additive and off by default until an admin enables it, so your bill today is still flat seats. Reading this before you switch it on is the cheaper order to do it in, because the decisions get harder to reverse once makers start building.

Do the patterns only apply to Microsoft agents?

They were extracted from Copilot work and the examples are Copilot-shaped, but the failure modes are not vendor-specific. The pattern that stops an agent answering outside its scope reads the same whichever platform you are on.

Buying this with a company card?

Most buyers expense it. Your receipt email carries a Generate link that opens an invoice generator: add your billing address, put your legal company name and any reference your finance team needs in the Additional notes box, and download the PDF. If you have an EU VAT number, enter it at checkout and no VAT is charged. Here is the approval email, so you do not have to write one.

Approval email

Subject: Approval request: Agent Instruction Block Design Guide ($19, one-time)

Hi [Manager],

I would like to expense a one-time $19 purchase: Agent Instruction Block Design Guide by Kesslernity.

What it is: Write agent instructions that behave. The fiftieth user gets the same result you did on day one.

What we get:
- 12 design patterns with before and after examples
- The failure mode each pattern prevents
- A review checklist for somebody else's instruction block

Why it is worth it: it is a one-time purchase with future updates included,
and it costs less than an hour of any consultant we would otherwise ask.
The author publishes the open-source Copilot prompt library that Microsoft's
CMO for AI at Work cited as "battle-tested in production environments".

A downloadable invoice is available from the purchase receipt for expenses.

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