Function is_protected_read 

pub fn is_protected_read(name: &str) -> bool

Explicit file-read tools whose result is the file content the agent reads and edits against. They must always return that content inline — never a head/tail digest (firewall) nor a stored-reference stub (reference_results) — regardless of output size or config. This is the single source of truth for “an explicit read always returns content”; both the firewall and the reference-results path honour it so a ctx_read can never degrade to a preview the agent can’t edit.