Claude Code's October release run tightened the blast radius: workspace trust, sandboxed writes, and a fast-mode sunset

Three releases in nine days — v2.1.309, v2.1.314, v2.1.316 — added an explicit trust gate on ultrareview, a setting that refuses file writes outside the working directory in every permission mode, idle-compaction for long-running sessions, and a deprecation notice for Opus 4.8 fast mode. None of it is a new feature; all of it is about what the tool is and isn't allowed to touch.