Composer-1 very slow

[dschaub (Darius Schaub)]

Describe the Bug

Since today, Composer-1 is much slower than before.

Steps to Reproduce

Just give any task to Composer-1.

Operating System

Windows 10/11

Current Cursor Version (Menu → About Cursor → Copy)

Version: 2.1.48 (system setup)
VSCode Version: 1.105.1
Commit: ce371ffbf5e240ca47f4b5f3f20efed084991120
Date: 2025-12-04T19:26:27.263Z
Electron: 37.7.0
Chromium: 138.0.7204.251
Node.js: 22.20.0
V8: 13.8.258.32-electron.0
OS: Windows_NT x64 10.0.26200

Does this stop you from using Cursor

Sometimes - I can sometimes use Cursor

[Dan_S1 (Dan S)]

Have noticed this too.

[tft]

I also encountered the same problem. It was originally the fastest model. Having gotten used to its previous speed, it is now almost unusable.

[k_allagbe (Kotchikpa Allagbe)]

this needs immediate attention

[deanrie]

Hey, thanks for the reports. We’re seeing multiple notes today about slow Composer 1 and are checking with the team.

Please help with diagnostics:

• Share 2-3 Request IDs from slow chat messages (message menu > Copy Request ID)
• A screenshot of Settings > Network > Run Diagnostics
• Confirm if it’s only Composer 1 or if other models are slow too

Quick checks:

• Settings > search “HTTP/2” > enable “Disable HTTP/2”, restart Cursor, then test
• Launch without extensions: cursor --disable-extensions
• Compare Composer-1 speed with another model in the same environment

Share the results and the requested data. If it isn’t a local configuration issue, we’ll raise the priority of the internal investigation.

[dschaub (Darius Schaub)]

In some cases composer gets even completely stuck when trying to edit a file (while being slow before that). see these examples:

59ebe97a-d98a-4c51-bfa2-f2e586ef46aa

7a072634-744f-416b-bb35-774c804a82f8

eee66e94-4da0-45a6-b555-dd9221485893

My network diagnostics look fine:

I also tested GPT-5 codex in the same workspace, it seems as slow as usual. I also tested it with HTTP/2 disabled.

Now also GPT 5 seems to get stuck when trying to edit a file.

[tft]

Hey team, same issue here, everything has become painfully slow lately, not just Composer-1. Pretty much every model gets stuck forever on “Planning next moves…” and file searching is basically frozen most of the time.

Here are two recent slow Request IDs:
0244d01f-912d-4060-a817-9018ddb753e0
0859a326-246e-445a-805c-0af1ed46d6c9

Quick background:

• I’ve been using Clash (VPN) for months with zero problems until very recently

• No new extensions installed

• HTTP/2 is already disabled (checked the box, restarted Cursor several times) → still using HTTP/1.1

• Tried launching with --disable-extensions → no difference

• Network diagnostics all green, ping looks normal

It honestly feels like something changed on the backend because the slowdown started for a lot of us at the same time. Happy to provide logs or anything else if needed. Thanks for looking into it!

[tft]

About 36 hours ago everything was still perfectly fine – suddenly it started getting worse and worse.
Now the hangs happen way more often, and honestly I don’t think it’s just a Composer-1 thing. I suspect the slowdown is happening on Cursor’s “background requests” in general (file indexing, codebase queries, autocomplete, etc.), not only on the big model interactions.

Composer-1 probably got the most complaints simply because it used to be lightning-fast, so when it drops to a crawl everyone notices immediately
GPT models have always been on the slower side, so people might just think “oh well, it’s normal” and not report it as much.

Anyway, just my two cents – feels like something changed globally on the backend or networking side rather than one specific model breaking.

[nontone]

I found this issue on model ‘auto’ since yesterday (in my timezone, all day) then email to support at night and found out that something might went wrong on network HTTP1.1 SSE (agent)

• very slow, struggle on ‘Planning next moves’
  • model
    • auto: struggle
    • gpt 5.1 codex [*any]: found same
    • composer 1: reach usage limit not try yet
• settings
  • already disable HTTP2
• network — HTTP compatibility mode
  • HTTP/1.1
    • ping slow, chat + agent being buffered by a proxy
  • HTTP/2
    • they works but very slow

what I’ve try

• disable VPN — no problem on VPN before
• use hotspot to my iPhone
• switching between wi-fi 2GHZ <—> 5GHZ
• restart router
• restart mac

I suspect after I update Cursor it might happen after GPT 5.1 codex release

• 03-04/12/2025 — works well
• 05/12/2025 — struggle all day / before cloudflare outage

[Galahad_Smith]

Where does the bug appear (feature/product)?

Somewhere else…

Describe the Bug

The Composer 1 model is nearly 4 times slower than before.

WWhy?

Steps to Reproduce

Just use it normally as you did before.

Expected Behavior

Just as fast as before.

Operating System

MacOS

Current Cursor Version (Menu → About Cursor → Copy)

Version: 2.2.14
VSCode Version: 1.105.1
Commit: 1685afce45886aa5579025ac7e077fc3d4369c50
Date: 2025-12-11T01:12:35.790Z (11 小时前)
Electron: 37.7.0
Chromium: 138.0.7204.251
Node.js: 22.20.0
V8: 13.8.258.32-electron.0
OS: Darwin arm64 23.1.0

For AI issues: which model did you use?

The Composer 1 model

Does this stop you from using Cursor

No - Cursor works, but with this issue

[Vishnu_Prasad_B]

I have mailed them and they are trying to pin it on some random proxy issue, whereas I am in open network!