Model from agent.md isn't recognized

[Arkoprabho]

Describe the bug

Consider a sample agent.md file under .github/agents/testing.md with content:

---
name: tester
description: Agent to represent copilot cli bug
model: Claude Haiku 4.5
---

On starting copilot cli and using this agent, the model doesn't change.
The same file on VSCode works as expected

Affected version

0.0.382 Commit: 18bf0ae

Steps to reproduce the behavior

Have an agents.md file

cat <<EOF > .github/agents/tester.md
---
name: tester
description: Agent to represent copilot cli bug
model: Claude Haiku 4.5
---
Other general instructions
EOF  

• Open copilot.
• Select this agent using /agent

Expected behavior

On selecting the agent, the model used by the agent should switch as per instructions in the md file

Additional context

No response

[jsburckhardt]

file name should be .github/agents/tester.agent.md - example -> https://docs.github.com/en/copilot/tutorials/customization-library/custom-agents/your-first-custom-agent#test-it-out

[Arkoprabho]

Missed that.
Though even with the file name corrected it isn't switching models on changing agents

[MattVevang]

Missed that. Though even with the file name corrected it isn't switching models on changing agents

+1. I placed the different agent spec files in my user profile folder (C:\Users\alias\.copilot\agents) and while the CLI sees them and takes on the defined persona it fails to use the defined model and I have tried numerous ones and formats for the text.

[devdnn]

Same with me, Model from agents file are only respected in VSCode Copilot Chat.

Copilot CLI uses what ever model is selected in the cli or the default CLI.

[SteveOfficerSeccl]

I have also run into this issue.

Exact same experience, VS Code respects the model choice but the CLI does not.
I have to explicitly provide the model via the command line args in order for it to be used

copilot --version
0.0.393
Commit: ea52078

[Ogekuri]

Confirmed on 0.0.400: /.github/agents/req.fix.agent.md: agent uses unsupported fields: model

[bagleytravis68]

This is kind of a major problem right? I know Copilot CLI is still catching up, but without the ability to switch models an agentic workflow may cost orders of magnitude more than it needs to.