Cursor Composer Not Working?
Composer (Ctrl+I / Cmd+I) not generating code, hanging, or producing blank diffs? The most common culprit is premium request quota — but context size and model choice matter too.
Live Status — Check These First
Composer routes requests through Anthropic (Claude) and OpenAI models. An outage on either kills Composer even when Cursor itself is Operational.
Composer vs Chat vs Tab: Know the Difference
| Feature | Shortcut | What it does | Request type |
|---|---|---|---|
| Composer | Ctrl+I / Cmd+I | Edits multiple files, applies diffs directly | Premium (fast) |
| Chat | Ctrl+L / Cmd+L | Q&A and code generation you copy manually | Regular |
| Tab completion | Tab | Inline single-line or block suggestions while typing | Regular |
| Background Agent | Ctrl+E / Cmd+E | Autonomous multi-step tasks in the background | Premium (fast) |
If Chat and Tab completions work but Composer does not, the problem is almost always premium request quota exhaustion — Composer draws from a separate pool that Chat does not touch.
Diagnose Your Specific Symptom
Composer opens but does nothing
Premium quota likely exhausted. Check Settings → Usage. Alternatively the model (e.g. claude-3-5-haiku) timed out on a complex task — switch to claude-3-7-sonnet.
Diff is empty or incomplete
Context too large. Remove @codebase and add only the specific files being changed with @file. Large contexts cause the model to skip or truncate edits.
Composer keeps looping or retrying
The AI model is rate-limited or the underlying API is degraded. Check Anthropic or OpenAI status. Switch to a different model from the dropdown inside Composer.
Chat works, Composer does not
Classic quota split. Regular Chat uses a different pool than Composer’s premium fast requests. Add your own API key in Settings → Models to bypass this entirely.
4-Step Fix in Order
- 1
Check your premium request quota
Open Cursor Settings (Ctrl+,) → Cursor Settings → Usage. You will see Fast Requests used vs. remaining for the current billing cycle. You can also go to
cursor.com/settingswhile signed in. Composer, Agent, and long multi-turn Chat sessions all draw from this pool. Quota resets at the start of each billing period — the exact date is shown in Settings.# Symptom: Chat responds, Composer hangs
# → Check Settings → Usage → Fast Requests remaining
# → 0 remaining = Composer will not generate until reset - 2
Reduce your Composer context
Composer has a context limit. Adding
@codebaseor many@filereferences bloats the context and causes Composer to hang or return empty diffs. Only include files that are directly involved in the change you want.❌ Overloaded — avoid this:
@codebase refactor the auth system
✅ Focused — do this instead:
@src/auth/session.ts @src/auth/middleware.ts
refactor session handling to use Redis - 3
Select the right model for the task
Inside Composer, click the model name in the bottom-left of the panel to switch models. The choice matters:
Model Best for Limitation claude-3-7-sonnet Complex multi-file refactors Slower, uses more premium quota claude-3-5-sonnet Most Composer tasks Good balance of speed and quality claude-3-5-haiku Speed, small targeted edits May skip steps on large tasks gpt-4o Alternative when Claude is degraded Different strengths — good fallback If one model provider is down (e.g. Anthropic), switching to a GPT model lets you keep working immediately.
- 4
Add your own API key to bypass Cursor limits
Go to Cursor Settings → Models and enter your Anthropic or OpenAI API key. With a BYO key, Composer requests draw directly from your key’s quota — they do not count against Cursor’s monthly premium request pool. This is the best workaround when you hit the Cursor limit mid-sprint and cannot wait for the reset.
Cursor Settings → Models → OpenAI API Key
Enter key → toggle "Use custom API key" → Composer now uses your key directly
You pay Anthropic or OpenAI directly at standard token rates. For heavy Composer use (~1M tokens/month) this is often cheaper than upgrading Cursor plans.
Composer vs Background Agent: Different Tools
A common source of confusion: Composer (Ctrl+I) and Background Agent (Ctrl+E) are not the same feature.
Synchronous — you stay in the editor, see diffs in real time, accept or reject changes step by step. Best for focused, bounded tasks you review immediately.
Asynchronous — runs in the cloud while you do other things, creates a branch, opens a PR. Best for longer tasks where you want fire-and-forget behavior. Available on Pro and Business plans.
If Background Agent is missing from your Cursor version, you may need to update or your plan may not include it. Composer is available on all paid plans.
Quick Resets to Try
Reload Cursor window
Ctrl+Shift+P → Reload Window. Reconnects to the AI backend without closing your workspace. Fixes most transient hangs.
Start a fresh Composer session
Close the current Composer panel, open a new one with Ctrl+I. Long Composer sessions accumulate context that can cause stalls.
Sign out and sign back in
Cursor Settings → Account → Sign Out, then sign in again. This re-validates your Pro subscription and refreshes the premium request counter display.
Update Cursor
Help → Check for Updates. Composer receives frequent updates. Older builds may misbehave when Cursor’s API protocol changes.
Get Alerted When Cursor Goes Down
Star Cursor, Anthropic, and OpenAI on Prismix. Get free email alerts the moment any of them experience degradation — know before Composer starts failing.
Frequently Asked Questions
Why is Cursor Composer not working or not generating code?
Most common causes: premium request quota exhausted (check Settings → Usage), context too large (remove @codebase, use specific @file references), wrong model selected (use claude-3-7-sonnet for complex tasks), or an Anthropic/OpenAI outage (check prismix.dev/service/anthropic).
How is Cursor Composer different from Cursor Chat?
Composer (Ctrl+I) edits multiple files and applies diffs directly to your codebase. It uses premium fast requests. Chat (Ctrl+L) answers questions and generates code you copy manually — it uses regular requests. If Chat works but Composer does not, your premium quota is exhausted.
How do I check my remaining Cursor premium requests?
Cursor Settings (Ctrl+,) → Cursor Settings → Usage. Or visit cursor.com/settings while signed in. The page shows Fast Requests used and remaining, and your reset date. Composer, Background Agent, and long Chat sessions all draw from this pool.
Can I bypass Cursor's premium request limit with my own API key?
Yes. Cursor Settings → Models → enter your Anthropic or OpenAI API key and toggle 'Use custom API key'. Composer will use your key's quota directly, bypassing Cursor's monthly pool. You pay the model provider at standard token rates.