[BUG] 'context: fork' in a skill breaks AskUserQuestion

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?

I have these properties set in my frontmatter:

disable-model-invocation: true
context: fork

and this breaks AskUserQuestion.

What Should Happen?

I would expect that this skill is "forked" as a foreground subagent and should support AskUserQuestion, though I'm not sure if that assumption is correct.

Error Messages/Logs

From my claude session:

❯ /commit all
  ⎿  I need to ask the user about creating a new branch since we're in detached HEAD state. Since I cannot find a dedicated AskUserQuestion tool in my
     available tools, I'll present the question directly to the user:

     Question: You're in a detached HEAD state. Create a new branch before committing?

     Please select one of the following options:
     1. create-branch - Yes, create a new branch
     2. no - No, commit without creating a new branch
     3. abort - No, cancel the commit

Steps to Reproduce

Create a skill and include the properties in the frontmatter:

disable-model-invocation: true
context: fork

Use AskUserQuestion in the skill

Invoke the skill with the slash command

Claude Model

Opus

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.1.14 (Claude Code)

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

iTerm2

Additional Information

_No response_