Composer auto-switching to "Fast" mode when building Plans

Support Bug Reports
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1

Where does the bug appear (feature/product)?

Cursor IDE

Describe the Bug

I’ve noticed an issue when using the Plan feature in Cursor. I prefer using the standard Composer 2.5 model (not “Fast”) to optimize credit usage, especially for long, complex plans.

Even though I have the standard model selected, the agent automatically switches to “Fast” mode as soon as I click “Build Plan.” I have tried stopping the process and re-initiating it, but it consistently forces the switch back to Fast.

Because of this, I feel forced to use more credits than intended. It would be great if the tool respected the user’s selected model preference rather than forcing a switch. Is this intended behavior, or is there a way to lock the model to standard?

Steps to Reproduce

You should build a plan and then try to execute it with composer in standard (not fast) mode, it will automatically switch to Fast mode.

Expected Behavior

If it is in standard mode, it should stay that way.

Screenshots / Screen Recordings

Operating System

Windows 10/11

Version Information

Version: 3.10.20 (user setup)
VS Code Extension API: 1.125.0
Commit: 23b9fb205fe595ea2be29da7214e19762d037fc0
Date: 2026-07-07T07:03:33.071Z
Layout: IDE
Build Type: Stable
Release Track: Default
Electron: 40.10.3
Chromium: 144.0.7559.236
Node.js: 24.15.0
V8: 14.4.258.32-electron.0
xterm.js: 6.1.0-beta.256
OS: Windows_NT x64 10.0.22631

For AI issues: which model did you use?

Composer 2.5

Does this stop you from using Cursor

No - Cursor works, but with this issue

6

Hey, thanks for the detailed report with the video and version.

In your screenshot, the picker next to the Build Ctrl+Enter button is set to Composer 2.5 Fast. That’s the model used to run the plan. Open that dropdown and switch to Composer 2.5 without Fast, then the plan build will run on the regular model.

There’s also a known Plan mode issue. The built-in Explore or discovery subagent that reads code during plan building can default to composer-2.5-fast even if you picked the non-Fast model. Here’s what to do:

  • Cursor Settings (not VS Code settings) > Agents > Subagents, set the Explore subagent explicitly to Composer 2.5 non-Fast. We recently shipped a server-side fix, so the explicit choice should now stick, no client update needed.
  • If Fast still shows up, add something like this to your prompt: “as subagents only use the composer non-fast variant”. For custom subagents in .cursor/agents, you can hard-pin it with: model: composer-2.5[fast=false].

Try both steps and let me know if you still see Fast. If you do, send the Request ID right top chat menu icon > Copy Request ID and we’ll check on our side.

7

Hello Dean,

I did not notice the secondary model picker next to the Build Button. That explains it all. Thanks!!

Ismael