Opus 5.5 Stuck at 1M Context!?

Support Bug Reports
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1

Describe the Bug

My Opus 5.5 is stuck at 1m context window even though its set to 300k? It just burnt my token limit and wasted my plan… I only noticed when I checked the context break down…

Steps to Reproduce

Use Opus 5.5 - set to 300k Context.

Expected Behavior

The model does not use 1M context.

Screenshots / Screen Recordings

Screen Shot 22-09-2026 at 22.53.png
Screen Shot 22-09-2026 at 22.53.png953×332 19.5 KB

Operating System

Windows 10/11

Version Information

Version: 3.13.21 (system setup)
VS Code Extension API: 1.128.0
Commit: 55434bd8062ece6fee083b82beed2aee42d253f0
Date: 2026-07-27T03:26:14.573Z
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 10.0.26200

For AI issues: which model did you use?

Opus 5.5

Does this stop you from using Cursor

No - Cursor works, but with this issue

7

Hey @Oneoone, thanks for the report and the screenshot. I’ve reproduced on our side and alerted the team. As a workaround, you can use Opus 5 rather than 5.5 as that does not appear to be impacted by this. Will keep you updated with any changes.

8

Hi Kevin,

Sadly, its a little too late for that.
Usage is mostly gone and 5.5 did do the task atleast.

Thanks for your time and help.

9

I tried Opus 5 and it has the same issue for me.

  • Start a new chat
  • Opus 5, 300k context
  • “Say Hi”
  • Cursor sets Context to 1M and the agent continues.
10

I just found that using the command /summarize - is the only thing that forces the context widow back to 300k

But only if you send the command in a message like:

"/summarize

And continue working"

Sending the command on its own doesnt work.

–Update–

Doesnt work on a 1 shot all the time - I have to spam some chats until it then says 300k

12

image
image788×413 13.7 KB

Never mind - tried it out and it doesn’t seem to stick to 300k

13

Sent you a follow up DM as well and we will keep you updated on a full resolution for this

14

i just burned usage with opus 5.5 usage :sob:, any chance we might get compensated for the fast consumption, just a small 3-4 msg chat consumes about 1-2% form the quota and im not even doing long horizon coding, just review and planning

15

Hi @Haris-Rahat-Dev, Sorry for the inconvenience here. I can’t compensate in this instance but I have reset your Grok bot usage limits as a courtesy.

16

welp no worries :cry:

17

Hey @Oneoone, following up: this is now fixed. With Opus 5.5 or Opus 5 set to 300K, the chat now runs against a 300K limit and summarizes before it gets there.

The fix was applied on our side, so you don’t need to update Cursor. If a chat is already past 300K, it will summarize on your next message.

@Haris-Rahat-Dev, the same applies to you. Thanks to you both for the reports. If you see the context grow past 300K again, please post a screenshot of Context Usage and the Request ID here.