Subagents Cannot Use Third-Party Model Providers

Background tasks or spawned subagents cannot use third-party model providers. They are limited to the default models included with the user’s GitHub Copilot subscription, and there is currently no way to assign a custom model to subagents.

Because I have reached my GitHub Copilot model quota and switched to a third-party provider as an alternative, I am no longer able to spawn subagents.

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| Field | Value |
| --- | --- |
| App version | 1.0.26 |
| OS | macOS 27.0.0 |
| Theme | GitHub |
| Path | /chat |
| Tenure | Week 3 |

The issue identifies the /chat path and concerns background tasks or spawned subagents. Start by tracing how subagent model selection is configured and how third-party providers are represented, then determine the design needed to assign a custom provider. Done means spawned subagents can use a selected third-party model instead of being limited to the subscription's default models.

Do mô hình lập chỉ mục viết ra từ nội dung của issue.