Hey, thanks for the detailed report with screenshots and the version, that really helps.
This is a known bug. The built-in Explore/discovery subagent in Plan mode resolves to composer-2.5-fast even when you’ve selected Composer 2.5 without Fast in settings. This is on our side, and I can’t share an ETA for a fix yet.
Workaround for now: in Settings > Agents > Subagents, set the Explore subagent to “Inherit from parent”. Then it will use the parent agent’s model non-Fast Composer 2.5 and avoid this bug.
Actually, i can’t use inherit from parent because I use Gpt 5.5 low or medium or Claude model to do the planning and then implement it using Composer 2.5 model. So Inherit > it will use gpt 5.5 low then?
if you do this indeed, another solution is just to specify which exact model you want to use as subagents (relyable from my testing), you don’t even need to input the exact string, I just say something in the lines of :
“and as subagents only use composer non fast variant please” or something in the lines of that
Yes, that’s right. Inherit from parent will pull in the parent model, so in your case GPT 5.5 low. For your setup planning on GPT 5.5 or Claude, implementation on Composer 2.5, that’s not what you want.
The best workaround is what @Tom_Coustols suggested. Tell it in the prompt that subagents should use the non-fast Composer. Something like and as subagents only use composer non fast variant please. You don’t need the exact model string, a normal instruction is enough.
If you’re using custom subagents via .cursor/agents, you can hard-pin the model in the frontmatter:
model: composer-2.5[fast=false]
But for the built-in Explore subagent in Plan mode, this syntax isn’t available yet, so you’ll need to rely on the in-prompt instruction there.
The bug with the built-in picker is on our side, and there’s no exact ETA for a fix yet. Let me know how it goes with the workaround.
Hey @Nafis_Islam_Kabbo quick update on this bug: it’s fixed on our side.
The fix is server-side, so you don’t need to update anything. Just go to Settings > Agents > Subagents and set the Explore subagent back to the regular Composer 2.5 non-Fast. It should now run in non-Fast without any in-prompt workaround.
Let me know if you still see it using the Fast version.
