[BUG] Skills with `context: fork` fail with "disable-model-invocation" when invoked via Skill tool (v2.1.113)

Environment

• Claude Code: v2.1.113
• Platform: Windows 11
• Session type: interactive CLI

Bug

Skills with context: fork in their SKILL.md frontmatter fail when invoked via the Skill tool:

Skill debug cannot be used with Skill tool due to disable-model-invocation

Repro

1. Create a skill with context: fork in frontmatter
2. In an active session, invoke it via the Skill tool: Skill("debug")
3. Error fires immediately — skill never executes

Key observation

Skills WITHOUT context: fork work fine in the same session (e.g. commit, implement).
Removing context: fork from the failing skills' frontmatter fixes the issue immediately.
This is specific to context: fork — the Skill tool itself is not broken.

Workaround

Remove context: fork from skill frontmatter. Skills run inline instead of forked.

Likely regression

v2.1.113 introduced native binary spawning. My guess: subagent spawning
for fork-context skills is broken in the native binary path.

Related: #47350 (context: fork using wrong model)