Unknown hook type: sessionStart

[CreateSun (啦啦啦种太阳)]

Where does the bug appear (feature/product)?

Cursor IDE

Describe the Bug

Configure “sessionStart” or ‘sessionEnd’ in .cursor/hook.json

Hooks tab in Cursor Settings can see errors:

ERROR: Invalid project config: Unknown hook type: sessionStart. Valid types are: beforeShellExecution, beforeMCPExecution, afterShellExecution, afterMCPExecution, beforeReadFile, afterFileEdit, beforeTabFileRead, afterTabFileEdit, stop, beforeSubmitPrompt, afterAgentResponse, afterAgentThought

Steps to Reproduce

.cursor/hook.json

{
  "version": 1,
  "hooks": {
    "sessionStart": [
      {
        "command": "./hooks/format.sh"
      }
    ]
    ]
  }
}

Expected Behavior

“sessionStart” or ‘sessionEnd’ could be recognized

Operating System

MacOS

Current Cursor Version (Menu → About Cursor → Copy)

Version: 2.3.41
VSCode Version: 1.105.1
Commit: 2ca326e0d1ce10956aea33d54c0e2d8c13c58a30
Date: 2026-01-16T19:14:00.150Z
Electron: 37.7.0
Chromium: 138.0.7204.251
Node.js: 22.20.0
V8: 13.8.258.32-electron.0
OS: Darwin arm64 24.6.0

Does this stop you from using Cursor

No - Cursor works, but with this issue

[deanrie]

Hey, thanks for the detailed investigation, it really helped.

You’re right, this is a bug. The docs do list sessionStart and sessionEnd as supported types, but the validation in Cursor Settings doesn’t recognize them.

I’ve passed this on to the team. I don’t have an exact ETA for a fix yet, but your report helps with prioritization.

Workaround: like you said, you can use beforeSubmitPrompt with an “already initialized?” check to emulate sessionStart.

I’ll post here if there’s any news on the fix.