Claude Code v2.1.280 adds Opus 5.5 as default model, mouse support, and multiple interface fixes

Anthropic released version 2.1.280 of Claude Code, marking the first update since the launch of Opus 5.5. The company set Opus 5.5 as the new default model in this release, replacing the prior default. Opus 5.5 provides a 1 million token context window and is priced at $4 per million tokens for input and $20 per million tokens for output, with an additional $0.20 per million tokens for cache reads.

The update adds mouse support to additional fullscreen interfaces. Users can now scroll the /skills list using the mouse wheel and click skill state options within the /plugin interface. A new environment variable, CLAUDE_CODE_MAX_MCP_DESCRIPTION_LENGTH, was introduced to override the 2,048-character cap on MCP tool descriptions and server instructions for the session.

Several interface stability issues were resolved. Dialogs that previously closed unintentionally when pressing Ctrl+C or Ctrl+D now behave as expected, and stray keystrokes no longer trigger unintended actions. Text input fields in dialogs no longer lose typed characters due to conflicting keybindings. Terminal rendering on Windows was fixed to prevent scrambled prompt lines after invisible characters were removed, and support for zero-width non-joiner characters in Persian and Arabic text was restored.

Voice dictation reliability was improved. The microphone now stops correctly when pressing Ctrl+C, Esc cancels dictation during transcript processing, and held Space no longer starts dictation from unintended views or modes. Session recovery and caching were also addressed. Switching models from a host app no longer causes prompt-cache misses, and resumed fork subagents now retain their original tool lists, preserving prompt caching for those agents.

Additional fixes include corrected display states for disabled skills in /plugin and /skills, restored Home and End key functionality in settings and selection lists, and corrected behavior for PgUp/PgDn in the /skills menu to prevent wrapping past the first or last item. The release also resolves a crash scenario triggered by corrupted cached message lists during long-running fullscreen sessions.