Composer 2 broken when custom OpenAI API Key is enabled

Support Bug Reports
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1

Where does the bug appear (feature/product)?

Cursor IDE

Describe the Bug

When a custom OpenAI API Key is enabled in settings, selecting Composer 2 returns “Bad Request: This model does not support custom API keys.” Composer 2 is a Cursor-proprietary model and should always route through Cursor’s servers, not through the custom OpenAI key. Auto and Premium modes work fine with the key enabled.

Steps to Reproduce

  1. Go to Settings → API Keys → Enable OpenAI API Key
  2. Select Composer 2 as the active model
  3. Send any message

Expected Behavior

Composer 2 should route through Cursor’s official servers regardless of custom API key settings, just like Auto and Premium already do.

Screenshots / Screen Recordings

20260330-035435.jpg
20260330-035435.jpg1104×849 88.8 KB

Operating System

MacOS

Version Information

Version: 2.7.0-pre.158.patch.0
VSCode Version: 1.105.1
Commit: 11e7a0514e3c19ee0ed19b37725c111fe5fb44f0
Date: 2026-03-28T10:42:16.149Z
Layout: editor
Build Type: Stable
Release Track: Nightly
Electron: 39.8.1
Chromium: 142.0.7444.265
Node.js: 22.22.1
V8: 14.2.231.22-electron.0
OS: Darwin arm64 25.4.0

For AI issues: which model did you use?

Composer 2

Additional Information

Disabling the OpenAI API Key fixes Composer 2, but then I lose access to GPT-5.4 via my own API. These should be independent — custom keys should only affect the corresponding provider’s models.

Does this stop you from using Cursor

Sometimes - I can sometimes use Cursor

1 Like
5

Hey, thanks for the report. This is a known issue. When a custom OpenAI API key is enabled, it’s mistakenly applied to all models, including Composer, which should always go through Cursor servers. This affects all Composer versions 1, 1.5, and 2.

Workaround: turn off the OpenAI API key before using Composer 2, then turn it back on for GPT-5.4. You can toggle it quickly with Cmd+Shift+0.

The team is aware, but there’s no ETA yet. I added your report for prioritization. The more users who report it, the more likely it’ll get fixed sooner.