[BUG] forkContext: true in subagent frontmatter is silently ignored

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?

forkContext: true does not fork context

What Should Happen?

forkContext: true should fork context

Error Messages/Logs

Steps to Reproduce

in subagent frontmatter set forkContext: true
subagent doesn't see conversation text

Claude Model

None

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.1.19

Platform

Anthropic API

Operating System

Ubuntu/Debian Linux

Terminal/Shell

Other

Additional Information

The Bug

Location: Line 269341 in function $4Y() (agent file parser)

let $ = O === "true", // BUG: Compares to STRING "true"

But the YAML parser (m31 = u31.parse at line 210145) converts true in frontmatter to boolean true, not string "true".

The check true === "true" returns false, and forkContext is silently disabled!