Function cmd_context_subagent 

pub fn cmd_context_subagent(
    root: &Path,
    goal: &str,
    files: &[String],
    symbols: &[String],
    budget: Option<usize>,
    json: bool,
) -> Result<()>

Subagent context policy (SCC-107, docs/API_AND_INTEGRATIONS.md §5): a narrower, tighter-budget task pack with explicit scope boundaries so delegated agents start from the same system model without re-deriving it.