Claude Code v2.1.280 Release Notes — What's New

What's changed

Added Claude Opus 5.5 (claude-opus-5-5), now the default Opus model — 1M context, $4/$20 per Mtok with $0.20/Mtok cache reads
Added mouse support to more lists in fullscreen mode: the wheel scrolls the /skills list, and a skill's state options in /plugin can be clicked
Added CLAUDE_CODE_MAX_MCP_DESCRIPTION_LENGTH to change the 2,048-character cap on MCP tool descriptions and server instructions for every MCP server in the session
Added hook output sizes and the number of oversized outputs saved to a file to the hook_execution_complete OpenTelemetry event
Fixed writes through a symlinked path being judged by their in-tree spelling: the prompt names where the write lands, and acceptEdits, allow rules and auto mode no longer approve one landing outside
Fixed auto mode retrying an action over and over when a safety check declined to review it; the action is now denied once, noting that retrying won't help
Fixed auto mode denying actions over and over without pause when a safety check gave no answer; retries now back off, and the turn stops with a message after ten in a row
Fixed Write calls failing validation when a model sends path, file_text, file_content or a stray description instead of file_path and content
Fixed Ctrl+C or Ctrl+D pressed twice in most dialogs (/model, /effort, /config, /status, /usage, /plugin, /sandbox, /permissions, /artifacts, /mobile, /login, /upgrade, /usage-credits, /install-github-app, /setup-bedrock, /setup-vertex) quitting Claude Code instead of closing the dialog
Fixed a click that only brought the terminal window to the front also triggering the item under the pointer — in search pickers, tab bars, agent/workflow rows, slash-command links and suggestion dropdowns
Fixed a stray n closing dialogs and a stray y confirming them; Enter and Esc accept and cancel (bind y/n to confirm:yes/confirm:no in keybindings.json to restore)
Fixed text fields in dialogs losing a typed letter, digit or Space to a keybinding on that key
Fixed the prompt line staying scrambled on Windows terminals after invisible characters were removed on Enter; the screen is now repainted so you review the exact text that will be sent
Fixed the invisible-character cleanup removing the zero-width non-joiner that Persian and Arabic text uses to attach a suffix to a Latin word or number, such as the plural of "PDF"
Fixed voice dictation not stopping on Ctrl+C (the prompt cleared but the microphone kept recording), Esc not cancelling while a transcript was processing, and held Space starting dictation from the transcript view and vim NORMAL mode
Fixed a model switch made from a host app (Claude Desktop, VS Code, SDK) while Claude is working causing a prompt-cache miss on the next prompt
Fixed resumed fork subagents rebuilding their tool list instead of re-sending the one they first used, which broke prompt caching for that agent
Fixed subagent hand-back messages showing an internal provenance preamble when expanded outside verbose mode
Fixed installed_plugins.json keeping the install-time commit after updating a plugin from a GitHub repository or git URL that tracks a branch or tag
Fixed skills in ~/.claude/skills/ being moved to ~/.claude/skills/.trash/ when a manifest.json in that folder listed their names
Fixed the session feedback survey showing no hover highlight on light and ANSI themes
Fixed /workflows briefly showing a one-row list before opening the only run
Fixed the mouse wheel not scrolling selection lists with hidden options (such as /model and /permissions) in fullscreen mode
Fixed a skill you switched off showing the same red ✘ as a plugin that failed to load in /plugin and /skills; off now shows a dim ◯
Fixed multi-select option descriptions being indented under the option number instead of under the label
Fixed the search box in /plugin, /skills and /mcp losing its right border in fullscreen mode
Fixed /mcp showing △ in the server list but ⚠ in the detail view for the same server; the list, detail views and /plugin now all show ⚠
Fixed Home and End doing nothing in the /config settings list and in selection lists such as /model, /memory and permission prompts
Fixed PgUp/PgDn in the /skills menu wrapping past the first or last skill instead of stopping there
Fixed Tab silently changing the selected setting's value in the /config list; it now does nothing there
Fixed conversations failing on every turn with a "role 'system' must precede an 'assistant' message" API error
Fixed conversations with the advisor on failing every turn with API Error 400 "Input tag 'advisor_20260301'" behind a proxy or gateway that doesn't support it; the request now retries without it
Fixed a session failing on every turn and /compact when its saved history held a malformed notice about MCP tools that could not be loaded
Fixed a crash when resuming a session whose saved transcript holds a malformed system message or a memory-saved notice without its file list
Fixed one cause of long-running fullscreen sessions exiting with "Claude Code exited after an unrecoverable interface error": a damaged cached message list is now rebuilt
Fixed Claude Code hanging when a settings file, or a file it re-reads after an edit, is replaced by a named pipe mid-read
Fixed /config crashing and some on/off preferences being misread when a preference that has moved to settings.json still holds a value like null or "false" in ~/.claude.json
Fixed resuming a session with unfinished background agents, shells or workflows starting a model turn on its own before you typed anything
Fixed messages sent to a background subagent being silently lost in headless and SDK sessions when the subagent was finishing its turn
Fixed a finished subagent's report being lost when the conversation that launched it was compacted before the report was read
Fixed background subagents being unable to use the LSP tool when an LSP plugin is active
Fixed background shell tasks reporting benign non-zero exits (e.g. grep with no matches) as failures
Fixed background sessions (claude --bg) being unable to run git, hooks, plugins and other helper programs when an environment variable handed to the session contained a NUL character
Fixed Ctrl+C needing three or four presses to exit while background subagents are running; two presses now exit
Fixed IDE selection being dropped when a sent prompt comes back into the input, such as pressing Esc to edit it, rewinding to it, or pressing Esc while startup hooks run
Fixed a ! shell-mode prompt stashed with Ctrl+S coming back as a plain prompt when restored, and / listing file paths right after stashing one
Fixed claude agents showing a blank, unresponsive screen instead of an error when the temp directory is full, not writable or owned by another user
Fixed an MCP server re-added under the same name after claude mcp remove still showing as needing authentication instead of reconnecting
Fixed background plugin marketplace auto-update ignoring git credential helpers, so private-repo marketplaces were re-cloned every run or never updated
Fixed claude plugin update clearing a plugin's recorded commit and moving it to version "unknown" when the official marketplace's snapshot file is a link or too large
Fixed the Artifact tool silently disappearing when your organization's policy can't be loaded (for example behind a web proxy); Claude now says what's blocking it
Fixed artifact republishes silently resetting stored database access rules or dropping the viewer profile scope when that capability was re-sent without them; they are now refused
Fixed /ultrareview

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