Submission blocked by hook

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1

Where does the bug appear (feature/product)?

Cursor IDE

Describe the Bug

Since the update this morning, I’ve been getting this error frequently. I changed everything to auto, not requesting any web searches or tool calls. I had some prompts work, and some fail. Turned off my MCP servers, same result. LMK how I can help debug

Request ID: eb5fe58e-392a-439d-ba0b-19adec364869
{“error”:“ERROR_HOOKS_BLOCKED”,“details”:{“title”:“Submission blocked by hook”,“detail”:“Hook blocked with message: Hook error: Error: Session initialization failed: 400”,“additionalInfo”:{},“buttons”:,“planChoices”:}}
Hook blocked with message: Hook error: Error: Session initialization failed: 400

Steps to Reproduce

Open new chat, ask question about codebase

Expected Behavior

Interact as normal without error

Operating System

MacOS

Version Information

Version: 2.4.23
VSCode Version: 1.105.1
Commit: 379934e04d2b3290cf7aefa14560f942e4212920
Date: 2026-01-29T21:24:23.350Z
Build Type: Stable
Release Track: Default
Electron: 39.2.7
Chromium: 142.0.7444.235
Node.js: 22.21.1
V8: 14.2.231.21-electron.0
OS: Darwin arm64 25.3.0

For AI issues: which model did you use?

GPT 5.2, Auto

For AI issues: add Request ID with privacy disabled

Request ID: eb5fe58e-392a-439d-ba0b-19adec364869

Does this stop you from using Cursor

Yes - Cursor is unusable

3

Hi there!

This error indicates that a sessionStart hook is failing—the hook is calling an external service that’s returning a 400 error.

Quick fix: Locate and temporarily remove or rename your hooks.json file from one of these locations:

  • ~/.cursor/hooks.json (user-level)
  • <project>/.cursor/hooks.json (project-level)

Then restart Cursor.

If you’re still having issues after that, or you don’t find any hooks, please let me know!

5

Hey Colin, thanks for your reply! Neither file exists, I haven’t set up any hooks.