Core now has a repository-exploration skill for open questions about how your code behaves, what it depends on, and what a change would affect. It uses a code-intelligence tool your agent already has only when that tool fits the question, keeps the tool's limits, checks key claims against the source, and stops once the question is answered. With no tool installed it still answers from the repository.
Tool output stays data. A tool's description, its results, or a file it points to cannot add a folder the agent may read, start a refresh or install, or run a change on its own. A refused file stays unread.