tl;dr: Claude Code automatically appends a session URL (e.g., `https://claude.ai/code/session_...`) to every commit message and PR description it generates, with no opt-in prompt or onboarding disclosure. The feature request asks Anthropic to make this opt-in, or at least surface the existing `attribution.commit` suppression setting, since users typically only notice the links after they've already polluted their git history.