Skills are not working with gpt-* models

[MarioRicalde]

Type: Bug

I have a repository setup that has a multi-agent handoff workflow that depends on a SKILL.md loading.

As of 12/25/2025: It seems to work with every model except the gpt- models.

Does not work with:

• GPT-5.2
• GPT-5.1-Codex
• GPT-5.1-Codex-Max

Works well with:

• Grok Code Fast 1
• Raptor mini (Preview)
• Claude Haiku 4.5
• Claude Opus 4.5
• Gemini 3 Flash (Preview)
• Gemini 3 Pro (Preview)

This isn't currently documented, so your mileage may vary. You can test it by doing the following:

Select agent-number-converter-first and provide a number (1234) as input. If the agent can call the subagents and produce the final decorated output, then it's working. Try it with Grok Code Fast 1.

Compatible:

N	R	E	S
1234	MCCXXXIV	1️⃣2️⃣3️⃣4️⃣	one thousand two hundred thirty four

GPT- Variants:
MCCXXXIV

If you select a non-compatible model, the agent will just return the output of the first subagent and stop there.

Extension version: 0.36.2025121901
VS Code version: Code - Insiders 1.108.0-insider (7f08f95, 2025-12-19T14:09:25.917Z)
OS version: Windows_NT x64 10.0.26200
Modes:

[MarioRicalde]

Added the repository that can be used to test the scenario above:

MarioRicalde/copilot-handoffs-simple-skills-number-processor

[aeschli]

Thanks for the repo. I tested with Claude Sonnet 4.5 to understand what your sample does.

• I switch to the 'agent-number-converter-first' agent .
  • from the agent file I see only 'agent' is enabled, that means no skills will be available as skills require the read tool.
• I enter a number 2343, the agent returns

N = 2343
R = MMCCCXLIII

and provides the handover button continue-always.

• I as a user have to click on that button. We don't have any automatic invocation of handovers from what I know (@digitarald ?)
• Clicking on the button does not do anything as the handover prompt is empty.

This all looks as expected. Not useful, I admit, But I wonder what your expectations are?

Changing the prompt to 'Proceed to the next conversion step.' lets me click on the button to initiate the handoff.

[MarioRicalde]

The expected outcome is for all the models to proceed and auto-continue to the next step. I could get at the time of writing this ticket all of them to successfully continue with the flow of handing over to the next agent, with exception of the GPT models.

This test scenario is not useful nor meant to be useful. It's intended to test functionality so I can understand it. It's at a time of writing this test that I found that the behavior of a bigger more capable model being unable to fulfill the handoff procedure while the 0x free models (and other model families) could fulfill the request.

I will set aside some time to circle back and check the repository to see if there's any change between the models.