[BUG] UserPromptSubmit hook does not anymore trigger with an initial prompt as argument

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

Before v2.0.77, until v2.0.76, the UserPromptSubmit used to trigger when starting claude with a prompt interactively.

Hook

{
  "hooks": {
    "UserPromptSubmit": [
      {
        "hooks": [
          {
            "type": "command",
            "command": "exit 1"
          }
        ]
      }
    ]
  }
}

% claude 'test'

 ▐▛███▜▌   Claude Code v2.1.3
▝▜█████▛▘  Opus 4.5 · Claude Max
  ▘▘ ▝▝    ~/code/workmux

❯ test
  ⎿  Interrupted · What should Claude do instead?

Hook does not trigger anymore.

What Should Happen?

% claude 'test'

 * ▐▛███▜▌ *   Claude Code v2.0.76
* ▝▜█████▛▘ *  Opus 4.5 · Claude Max

> test
  ⎿  UserPromptSubmit hook error
  ⎿  Interrupted · What should Claude do instead?

Hook triggers correctly

Steps to Reproduce

Use a hook like this:

{
  "hooks": {
    "UserPromptSubmit": [
      {
        "hooks": [
          {
            "type": "command",
            "command": "exit 1"
          }
        ]
      }
    ]
  }
}

Start claude with claude 'test', and notice how there is no output from the hook.

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

2.0.76

Claude Code Version

2.1.3

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

My tool, workmux, relied on this behavior to detect new started agents from this hook firing, and calling workmux set-window-status working. https://github.com/raine/workmux/blob/main/.claude-plugin/plugin.json#L12-L21

Would appreciate if it's fixed 🙏