Literal strings that begin a tool call. Used to hold markup back while streaming.
Extracts every tool call from text, returning them with the text that
remains. A block that can't be parsed, or that contains a call accept
rejects, must be left in text untouched.
Optionalaccept: (toolName: string) => boolean
Recognizes one text-based tool-call format that some models emit in place of native tool calls.