<h2>What's changed</h2> <ul> <li>Added Claude Opus 5.5 (<code>claude-opus-5-5</code>), now the default Opus model — 1M context, $4/$20 per Mtok with $0.20/Mtok cache reads</li> <li>Added mouse support to more lists in fullscreen mode: the wheel scrolls the <code>/skills</code> list, and a skill's state options in <code>/plugin</code> can be clicked</li> <li>Added <code>CLAUDE_CODE_MAX_MCP_DESCRIPTION_LENGTH</code> to change the 2,048-character cap on MCP tool descriptions and server instructions for every MCP server in the session</li> <li>Added hook output sizes and the number of oversized ou