Claude Code v2.1.280 Release — Adds Claude Opus 5.5 and enhanced usability improvements

By the editors ／ Model: gemma-4-26b-a4b-it-qat-6bitAs of: 2026-09-23 / Updated: 2026-09-24

Claude Code v2.1.280 has been released, introducing several key functional updates and addressing a wide range of stability issues.

New Features and Improvements

Model Update: Added Claude Opus 5.5 (claude-opus-5-5) as the default Opus model for Pro and Team Standard plans, featuring a 1M context window.
MCP Configuration: Introduced CLAUDE_CODE_MAX_MCP_DESCRIPTION_LENGTH to allow users to adjust the 2,048-character limit on MCP tool descriptions and server instructions.
VS Code Enhancements: Added new dialogs for Status, Sandbox, Claude in Chrome, and conversation exports, alongside improved prompt and text handling.
Slack Integration: Added native working indicators, stop buttons, and thread titles to Claude's threads within Slack channels.
UI/UX Improvements: Added mouse scroll support for fullscreen lists, improved workflow progress indicators, and enhanced file suggestions via the @ symbol.

Bug Fixes

Stability: Resolved issues where Claude Code would hang or exit during specific background tasks, file operations, or when handling malformed session data.
Terminal & UI: Fixed various dialog issues involving keyboard shortcuts (Ctrl+C/Ctrl+D), screen repainting on Windows, and improper scrolling in fullscreen mode.
API & Connectivity: Fixed errors related to API request retries in proxy environments and resolved authentication issues in cloud-based sessions.
Model & Tooling: Corrected validation failures for model write calls and addressed issues where subagents were incorrectly rebuilding tool lists.

Sources