Agents should be able to pick exact models for subagents

Feature request for product/service

Background Agent (GitHub, Slack, Linear,…)

Describe the request

there are circumstances where I want to instruct the model to spin up subagents with other models, and they are not able to. For whatever reason they ahve a restricted set (fast, etc..) instead of also allowing “Gpt-5.4” as options. Please add full model selection as well.

Operating System (if it applies)

MacOS