Prompt files and skills
When a slash-command prompt file is enough and when a skill earns its folder — building /new-engagement and the meeting-prep skill.
- Tell a prompt file apart from a skill and know when each is right
- Build a reusable slash command for scaffolding an engagement
- Package a repeatable task as a skill with its own resources
The starter prompt in this lesson targets VS Code’s Local agent. That agent
still accepts .prompt.md slash commands; Agent Host sessions do not load them.
For Agent Host, migrate the procedure to a skill before running it.⊙
Skills are
SKILL.md folders — an Anthropic-originated open standard that Copilot adopted —
discovered from .github/skills/ and enabled by default across the editor, the
CLI, and the cloud agent.⊙
When a prompt file is enough
For the Local agent, a prompt file can capture a procedure without additional resources. Scaffolding a new engagement is an example:
---
description: Scaffold a new engagement repo from the template and personalize the instruction files.
mode: agent
---
# The Demo Harness — drewbreyer.com/harness — starter file, as of 2026-07-06
Scaffold a new customer engagement in this workspace.
1. Create the numbered artifact folders: 00-intake, 01-research, 02-discovery,
03-model, 04-data, 05-agents, 06-rehearsal, 07-leave-behind.
2. Copy the .github/ instruction stack, agents, prompts, skills, and hooks, plus
.vscode/mcp.json and AGENTS.md, from the template.
3. Ask me for the customer name, the opportunity, and the compete, then
personalize copilot-instructions.md with those specifics.
4. Leave 00-intake/ with a README that lists what may and may not live in the
repo (public research and my notes yes; customer data of record no).
Report the tree you created and the questions you still need answered.
Invoked as /new-engagement, it creates the numbered folders, copies the
instruction stack, and personalizes the constitution by asking you for the
specifics. No resources, no scripts — just a well-worn procedure, captured.
When a skill earns its folder
A skill earns the extra folder when the task needs to carry resources alongside the instructions — a template to fill, a checklist to apply, a script to run. The meeting-prep task is a skill because it ships a fixed one-page brief template and a pre-meeting checklist, and the judgment about how to assemble a brief lives with those resources:
---
name: meeting-prep
description: Assemble a one-page pre-meeting brief from the dossier, the findings, and pasted calendar context.
---
# The Demo Harness — drewbreyer.com/harness — starter file, as of 2026-07-06
# Meeting prep
Produce a single page a seller can read in the elevator.
## When to use
Before any customer meeting once 01-research/ and 02-discovery/ exist. This is a
skill rather than a prompt file because it carries a fixed brief template and a
short checklist as resources.
## Steps
1. Read 01-research/dossier.md and 02-discovery/findings.md.
2. Take the meeting's attendees and agenda from what the user pastes (calendar
context is not in this repo).
3. Fill brief-template.md: who is in the room and what each cares about, the
three things we believe, the two questions we must ask, and the one risk.
4. Keep it to one page. Cite each product claim; leave anything uncertain out.
## Resources
- brief-template.md — the one-page layout.
- checklist.md — the pre-meeting read.
Use a skill when the task needs templates or scripts, or when the selected harness does not load prompt files. Keep the steps and resources together.
In the field
Choose the session target first. Run the starter prompt with the Local agent,
or convert its body to a SKILL.md for Agent Host. Then run the meeting-prep
skill and check that it uses its template and checklist.
- .github/prompts/new-engagement.prompt.md — the scaffold command
- .github/skills/meeting-prep/SKILL.md — the meeting-prep skill