Sub-Agent Model still not deterministic

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1

Where does the bug appear (feature/product)?

Cursor IDE

Describe the Bug

Cursor still sometimes launches a sub-agent with a different model than the one the parent chat is using. I have “Default Model” set to Last Used. I am using Composer 2.5. It just launched a sub-agent with Claude Sonnet 5 High >:[

Attached screenshot shows Default Model setting, main chat model, and subagent model.

Steps to Reproduce

Use the Superpowers “code-reviewer” skill. It launches a subagent to perform the actual review.

Expected Behavior

It should use Last Used model. I expect that to be the model that was currently in use when the subagent was launched.

Screenshots / Screen Recordings

Screenshot 2026-09-24 084211.png
Screenshot 2026-09-24 084211.png1331×626 34.7 KB

Operating System

Windows 10/11

Version Information

Version: 3.21.18 (user setup)
VS Code Extension API: 1.128.0
Commit: c4730f7d93d787d9ab120af715999f0345ee5bc0
Date: 2026-09-22T02:04:34.641Z
Layout: IDE
Build Type: Stable
Release Track: Default
Electron: 42.10.0
Chromium: 148.0.7778.280
Node.js: 24.18.1
V8: 14.8.178.38-electron.0
xterm.js: 6.1.0-beta.291
OS: Windows_NT x64 10.0.26200

For AI issues: which model did you use?

Composer 2.5.

For AI issues: add Request ID with privacy disabled

b2aed216-932c-4e93-be06-6e1443d20063

Additional Information

I’m not sure if this is an AI issue.
It seems like the agent harness could dispatch the subagent using the application settings regardless of what the LLM wants.

Does this stop you from using Cursor

No - Cursor works, but with this issue

7

Hey @Charles_Wood, thanks for the report and request ID.

The “Default Model: Last Used” setting controls which model a new chat starts with. Subagents normally inherit the parent model, but an explicit model included in the subagent call currently takes precedence. In this session, Composer 2.5 explicitly selected Claude Sonnet 5 High when launching the review. Your other recent subagents inherited Composer 2.5 as expected.

This is a known issue we’re tracking.

For regular subagents launched from the local IDE, disabling Claude Sonnet 5 under Cursor Settings > Models removes it from the models Agent can select. Model settings are not yet a universal enforcement boundary for every Cloud or specialized subagent path, so please share another request ID if a disabled model is still used. You can also add a User Rule such as: “When launching subagents, never specify a model. Always inherit the current chat’s model.” Rules guide Agent but are not hard enforcement.

8

Hm, I had disabled most models. I guess updates are re-enabling some of the flagship models.

Thanks for the quick reply.