Skills are not used unless explicitely stated

### Describe the bug

Hi,

Not sure if this is a Copilot issue or a model issue (I'm using Claude Sonnet 4.5 99% of the time).
I've tried creating Skills to have a lighter AGENTS.md file.

It seems that Copilot will not trigger the skill use unless told to.
Here is an example with explicit skill usage statement :

This works fine.

Here is the same prompt (in a new chat) without mentioning skill usage:

Here is my skill frontmatter as reference :
```md
---
name: writing-tests
description: Guide for writing tests on this project (unit and functional). Use when creating or modifying tests (files in the @project/tests directory).
---
```

The SKILL.md file is placed in the right folder :

And Copilot sees it since it appears in `/skills list`

I've tried to include a statement about using skills in my `AGENTS.md` file but it seems to have no effect (perhaps too many instructions around the statement tho).

Should the frontmatter be formatted another way to have more success? Any ideas how to enhance this?

Thanks!

### Affected version

0.0.382 Commit: 18bf0ae

### Steps to reproduce the behavior

_No response_

### Expected behavior

Skills should be used when needed, without having to give special instructions to do so.

### Additional context

- Log file with skill usage: [process-1768470203521-12242.log](https://github.com/user-attachments/files/24637412/process-1768470203521-12242.log)
- Log file without skill usage : [process-1768470338802-12884.log](https://github.com/user-attachments/files/24637411/process-1768470338802-12884.log)