Apply Model Failing with Claude 3.5 – Code Generated but Not Applied

(v0.45.14 on macOS)

Description:

I’m experiencing a critical issue when using Claude 3.5 in Cursor v0.45.14 on macOS.

  • I asked Claude to fix incorrect MDX formatting in a file.
  • Claude generated a correct fix on the first try.
  • However, it immediately said, “That edit wasn’t quite right, let me try again…”
  • It then entered a loop of retry attempts, each progressively deleting more code from the file. By the 9th attempt, it had effectively deleted the entire component/page.

Separately, I’ve also noticed:

  • Claude hangs for several minutes when making code requests, often ending in a “lost connection to Claude” or “try again” message.
  • After several failed application attempts, Claude eventually states:

“I apologize but it seems that the apply model is having difficulty making the necessary changes to fix the JSX structure. Would you like me to suggest a specific manual fix?”

This implies that:

  • Claude can generate working code and identify the issue, but
  • The apply model fails when attempting to inject that code into the project, leading to infinite retry loops or complete failure to apply the fix.

This appears to be a bug specifically with Cursor’s code application layer, not the Claude model itself.

Steps to Reproduce:

  1. Request a JSX or MDX fix using Claude 3.5.
  2. Wait for multiple attempts.
  3. Observe progressive deletion, retry loops, and eventual failure message referencing the apply model.

Expected:
Claude should apply generated code successfully or fail gracefully without entering an error loop or progressively deleting code.

Actual:
Claude generates code → apply model fails → infinite retries → file is damaged or wiped → user is told apply model is broken.

Would appreciate confirmation if this is being investigated. Happy to provide logs or repro steps if needed.