Where does the bug appear (feature/product)? Cursor CLI Describe the Bug I always run prompts using the standard Composer 2.5 mode. However, starting today, Cursor began automatically spawning Composer 2.5 Fast subagents even though I never selected the Fast mode. This behavior is extremely frustr…

Hey, thanks for the detailed report. I can see the log showing "model":"composer-2.5-fast" on the Task calls, that really helps. This is a known bug. In some cases, subagents resolve to the fast variant composer-2.5-fast instead of the regular composer-2.5 when the model isn’t explicitly set in the…

Hey, I also encountered this issue, but I’m on the IDE side. I configured the sub-agent option in Cursor settings — I selected Composer 2.5, used edit mode, and turned off fast mode. However, when I use Opus 4.8 to do planning, the sub-agent still chooses Composer 2.5 - fast, which causes my usage …

Hey, thanks for following up. Yep, it’s the same known bug, just on the IDE side. The subagent gets resolved to composer-2.5-fast even though the settings have regular Composer 2.5 selected with fast turned off. We can reproduce it and it’s been reported internally. I can’t share a fix timeline yet. …

[image] Bug: IDE Sub-agent (Composer 2.5) Forcibly Uses Fast Mode Despite User Setting Bug Reports Where does the bug appear (feature/product)? Cursor IDE Describe the Bug I configured the sub-agent option in Cursor settings — I selected Composer 2.5, used edi…

hi dean, just a follow-up seems like even with ‘model: inherit’ cli specifically still routes to fast mode. it seems like this problem happens much more on cli. any other method I could leverage? anyway to just “turn off” fast mode completely on my account?

Thanks for coming back with details. The fact that model: inherit on the CLI still ends up using fast mode is a useful signal, I added that to the report. Confirmed, this bug shows up much more aggressively on the CLI than in the IDE. To answer your questions honestly: There isn’t a reliable work…

Hi Dean, Could you confirm if this solution given by Sam is correct? [image]

Hey, I’ll give an honest answer because there’s a nuance here. The mechanism itself, explicitly setting the option via fast=false, is correct. But right now we only have a confirmed working case at the SDK level using params: [{ id: "fast", value: "false" }], you can see it in this thread: Cursor C…

hi dean, For inheriting the parent model, it’s more reliable to fully remove the model field from the frontmatter, instead of setting model: inherit, since inherit doesn’t always work on the CLI. is this the latest and best option we have currently? it contradicts with what you suggested earlier…

Hey, thanks for flagging this. We found a more reliable approach just a few days ago, so the earlier tip to use model: inherit is no longer relevant. On the CLI, inherit doesn’t work consistently, and our latest tests confirmed that. The best option right now is to remove the model field from the f…

CLI subagents changing model to composer 2.5 fast mode by itself

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Gopher (Jayson) June 9, 2026, 8:40am 10

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CLI subagents changing model to composer 2.5 fast mode by itself

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