Issues with Agent Mode switching to "Fast Mode" models

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1

I was using Agent Mode with the Claude model specifically.

However, it occasionally triggers sub-agents under the hood that use models I didn’t select, often defaulting to ‘fast mode.’ Is there a way to disable these sub-agents from using the composer-2-fast model, or can we specify which model the sub-agent should use?"

Thanks

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i didn’t add or included any of the subagent in the ‘Rules, Skills, Subagents’ setting as well

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3

Hey, thanks for the request. I can see the dashboard screenshots.

This is expected behavior. Your main agent is running on Claude, as you selected. But when the agent needs to do helper tasks like searching the codebase, running terminal commands, or using the browser, it automatically launches built-in sub-agents like Explore, Bash, and Browser. Those use the default fast model, which is why you see composer-2-fast in the dashboard.

The sub-agent’s output is sent back to the main agent, which then processes it through Claude.

If you want sub-agents to use your model too, you’ve got a few options:

  • Create custom sub-agents with model: inherit in .cursor/agents/ so they use the parent agent’s model. Format is here: Subagents | Cursor Docs
  • Turn on Max Mode in chat settings
  • Ask the agent not to launch sub-agents: “Do NOT launch sub-agents for this task”

More details on sub-agents and why they use a fast model are in the docs above.

Let me know if you’ve got any other questions.

4

Thanks ! let we play around and study that

5

HI

I’ve selected the standard Composer model:

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But the agent launched composer-fast:

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Why did that happen?

6

Hey, thanks for the report. I can see the screenshots. The Explore subagent is set to Composer 2.5, but the dashboard usage is billed to composer-2.5-fast.

These are two different things. By default, the Explore subagent does run on Composer 2.5 Fast. That’s expected behavior for helper tasks like code search. But if you explicitly selected Composer 2.5 with Fast turned off and it still resolves to Fast, that’s a known regression. We reproduced it, and it still happens in the latest versions. We’re tracking it on our side, and I’ll follow up as soon as there’s an update.

Full thread about the same issue (you can subscribe to get updates):

For now, as a temporary workaround:

  • Pick a subagent model that doesn’t switch to a Fast variant. That worked as a workaround in that thread.
  • Or set a custom subagent with model: inherit in .cursor/agents/ so it inherits the parent model: Subagents | Cursor Docs
  • Or for that specific task, ask the agent not to launch sub-agents: Do NOT launch sub-agents for this task

Quick question to confirm. In the Explore subagent settings, was Fast definitely turned off (via hover → edit)? That’ll help confirm you’re hitting the same regression and not the default behavior.

7

Hi

Yes, it was definitely turned off. That’s why I was surprised, since I hadn’t enabled fast mode. After it happened, I went into the subagent settings, opened the model, and enabled fast mode—after that, it was clearly reflected in the UI (“Composer 2.5 Fast”).

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8

Thanks for confirming the settings. Yep, this is the exact known regression we mentioned above: the Explore subagent still resolves to Composer 2.5 Fast even when Fast is turned off. We can reproduce it too, including on the latest versions.

As a temporary workaround, pick a subagent model that doesn’t switch to a Fast variant. That worked in nearby threads. Options:

  • Create a custom subagent with model: inherit in .cursor/agents/ so it inherits the parent model: Subagents | Cursor Docs
  • For a specific task, tell the agent not to launch sub-agents: Do NOT launch sub-agents for this task

You can subscribe to the main thread. I’ll post an update there as soon as I have one: Explore agents ignoring model variant

11

Hey everyone, status is unchanged. The bug is known and reproducible, including on the latest versions. I can’t share an ETA for a fix yet, but as soon as I have an update I’ll post it in the main thread. You can subscribe there: Explore agents ignoring model variant

About the quota: to stop Explore from switching to the Fast variant right now, here are a couple workarounds:

  • Pick a model for the sub-agent that doesn’t have a Fast toggle. This helped in related threads.
  • Create a custom sub-agent with model: inherit in .cursor/agents/, so it inherits the parent model: Subagents | Cursor Docs
  • For a specific task, tell the agent not to launch sub-agents: Do NOT launch sub-agents for this task

Let me know if the workaround doesn’t fix the usage issue and we can dig in.

12

Hi @deanrie
Do we have any progress on a fix for this issue?

13

Hey @bcb-marc. Quick update: a fix for this regression is already in our team backlog. I can’t share an exact release date yet, but as soon as I have an update I’ll post it in the main thread. I’d recommend subscribing here: Explore agents ignoring model variant

Until the fix is shipped, here are working workarounds to keep Explore from switching to the Fast variant:

  • Pick a sub-agent model that doesn’t have the Fast toggle. This helped in related threads.
  • Create a custom sub-agent with model: inherit in .cursor/agents/ so it inherits the parent model: Subagents | Cursor Docs
  • For a specific task, tell the agent not to launch sub-agents: Do NOT launch sub-agents for this task

If none of these reduce the extra quota usage, let me know and we’ll dig in.