Complete native tool objects arrive in chunks; arguments are NOT OpenAI
string deltas. All tools remain open until done:true, exact usage and EOF.
created_at is per chunk and may change; a local UUID labels the join scope,
never pretends to be a provider response ID and never enters request bytes.
Complete native tool objects arrive in chunks; arguments are NOT OpenAI string deltas. All tools remain open until done:true, exact usage and EOF. created_at is per chunk and may change; a local UUID labels the join scope, never pretends to be a provider response ID and never enters request bytes.