Cursor automatically invokes Claude 4.5 long-context mode (context-1m-2025-08-07), increasing costs and hitting Bedrock rate limits

[StergiosDikos]

Where does the bug appear (feature/product)?

Cursor IDE

Describe the Bug

Since around the 24th of Oct 2025, Cursor’s Bedrock integration for Claude Sonnet 4.5 automatically includes the following field in API calls:

"anthropic_beta": ["context-1m-2025-08-07"]

This flag explicitly enables the 1-million token context mode on AWS Bedrock.
That mode:

• Doubles token pricing ($0.003 → $0.006 input, $0.015 → $0.0225 output per 1K tokens)
• Uses a separate, much lower quota pool (preview feature with stricter rate limits)
• Is not user-configurable or documented in Cursor settings

Example CloudWatch log extract:

"thinking": {"type": "enabled", "budget_tokens": 6000},
"anthropic_beta": ["context-1m-2025-08-07"]

Even small requests (<200K tokens) are billed and throttled under the long-context tier.
This appears to have been introduced recently, as older requests used the 200K mode without the beta flag.

While having access to the 1M context window is a much welcome feature, it should be on-demand and invoked only with user consent.
Enabling it automatically makes the product effectively unusable for AWS Bedrock users due to the higher cost and much stricter service quotas associated with the long-context mode.

Requests:

1. Confirm whether this behavior is intentional.
2. Add a setting or environment variable to disable long-context mode.
3. Make the 1M context window available only on user opt-in, not by default.

Steps to Reproduce

1. Open Cursor IDE and select Claude Sonnet 4.5 as the model (via AWS Bedrock key).

2. Send any prompt - it can be small, e.g. 1+1= (see screenshot)

3. Check your AWS CloudWatch logs for the corresponding InvokeModelWithResponseStream event.

4. Observe that the request payload includes:

   "anthropic_beta": ["context-1m-2025-08-07"]
   

5. Note that the same request is billed under Claude Sonnet 4.5 – Long Context pricing and is subject to stricter rate limits, even though the input is below 200K tokens.

Expected Behavior

Cursor should default to 200K context mode unless the user explicitly choses to enable the 1M context mode.

Screenshots / Screen Recordings

Operating System

MacOS

Current Cursor Version (Menu → About Cursor → Copy)

Version: 1.7.54
VSCode Version: 1.99.3
Commit: 5c17eb2968a37f66bc6662f48d6356a100b67be0
Date: 2025-10-21T19:07:38.476Z
Electron: 34.5.8
Chromium: 132.0.6834.210
Node.js: 20.19.1
V8: 13.2.152.41-electron.0
OS: Darwin arm64 24.5.0

For AI issues: which model did you use?

us.anthropic.claude-sonnet-4-5-20250929-v1:0
global.anthropic.claude-sonnet-4-5-20250929-v1:0

For AI issues: add Request ID with privacy disabled

Request ID: 8d740de6-b688-4c4a-b652-1769519fa073

Error:

ERROR_OPENAI_RATE_LIMIT_EXCEEDED
Hit your Anthropic API key rate limit.
You're using your own API key, and we received a rate limit error from Anthropic.

Severity: High - this behavior is leading to substantial unexpected billing (hundreds of dollars per day) and makes Cursor unusable under AWS Bedrock quotas for the 1M context model.

Does this stop you from using Cursor

Yes - Cursor is unusable

[deanrie]

Thanks for the detailed bug report! This is a serious issue, auto‑enabling the 1M context mode without user control should not happen.

I’ll pass this to the team, since it makes Cursor unusable for Bedrock users and can cause unexpected costs.

As a temporary workaround until we ship a fix, please try:

• Temporarily using a different model (if available in your Bedrock setup)
• Switching to direct Anthropic API keys if that fits your workflow

[StergiosDikos]

Thank you, I appreciate the quick response.

I switched to Claude Sonnet 4, and it seems to have the same issue (see screenshot). I also verified it in AWS CloudWatch, where the request payload includes:

"anthropic_beta": [
    "context-1m-2025-08-07"
]

So the 1M context mode is being enabled automatically for Sonnet 4 as well.

For context, we have special pricing and AWS credits tied to Bedrock usage, so switching to the direct Anthropic API isn’t a viable workaround.

The main issue is quota: the 1M context mode is still in BETA with only 2 RPM vs 200 RPM for the standard mode - a 100x reduction that’s causing immediate rate limits.
We’ve requested a service quota increase from AWS for the 1M mode as a temporary workaround, but approvals typically take a couple of weeks - leaving us unable to use Cursor.

In the meantime, I am looking for a way to intercept and strip the anthropic_beta header from Bedrock API requests (either via API Gateway proxy or local request interception) if you know if this would work or have any workaround please let me know - ideally though this gets sorted quickly.

[deanrie]

Thanks for the additional info, the team will check it.