Claude Opus 5.5 arrives as the default Opus with expanded context; a sweeping stability pass hardens sessions, agents and plugins, while VS Code gains in-panel workflow controls.
claude-opus-5-5), now the default Opus model — 1M context, $4/$20 per Mtok with $0.20/Mtok cache reads/skills list, and a skill's state options in /plugin can be clickedCLAUDE_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 sessionhook_execution_complete OpenTelemetry event/status, showing the session's version, account, model and server details/sandbox/chrome/export, to copy or save the conversation as plain text/skills that opens it/plan that switches to plan mode, sends a first planning prompt, or shows the session's plan/permissions: focus returns to the rule list after viewing, adding or deleting a rule, and the delete-rule and remove-directory confirmations now default to No/permissions tab navigation: ←/→ and Tab pressed in a rule list now switch tabs without moving focus to the tab bar/cost cache-miss causes to name thinking mode and thinking display changes/install-github-app: the GitHub CLI check and repository selection steps now show "Esc to cancel"/artifacts and /workflows lists: a scrollbar at the right edge shows how much of a long list is hidden and where you are in it/plugin's Add Marketplace form in fullscreen: it no longer draws a box inside the pane, and its text and key hints line up with the rest of /plugin/workflows detail view in fullscreen: it no longer draws a second horizontal rule under the pane's divider/btw asked while a tool is still running: the side question now knows that call is in progress instead of reading it as a failed one@ file suggestions: a file whose name contains the query now ranks above one that only matches across its folder names/ultrareview uploads: renamed copies of key files, such as id_rsa copy or kubeconfig (1).yaml, now also stay on your machine--debug-file writes a debug log to a path you chooseacceptEdits, allow rules and auto mode no longer approve one landing outsidepath, file_text, file_content or a stray description instead of file_path and content/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 dialogn 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)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~/.claude/skills/ being moved to ~/.claude/skills/.trash/ when a manifest.json in that folder listed their names/workflows briefly showing a one-row list before opening the only run/model and /permissions) in fullscreen mode/plugin and /skills; off now shows a dim ◯/plugin, /skills and /mcp losing its right border in fullscreen mode/mcp showing △ in the server list but ⚠ in the detail view for the same server; the list, detail views and /plugin now all show ⚠/config settings list and in selection lists such as /model, /memory and permission prompts/skills menu wrapping past the first or last skill instead of stopping there/config list; it now does nothing there/compact when its saved history held a malformed notice about MCP tools that could not be loaded/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.jsonclaude --bg) being unable to run git, hooks, plugins and other helper programs when an environment variable handed to the session contained a NUL character! shell-mode prompt stashed with Ctrl+S coming back as a plain prompt when restored, and / listing file paths right after stashing oneclaude agents showing a blank, unresponsive screen instead of an error when the temp directory is full, not writable or owned by another userclaude mcp remove still showing as needing authentication instead of reconnectingclaude 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/ultrareview reporting a stopped cloud review as completed or as an error to retry, and waiting out the full timeout when its session was deleted or the signed-in account changed~/.claude/session-env, image-cache or another cleaned-up folder/effort became per-model to no longer apply to newly released models such as Opus 5.5; they start at their default until you pick a level/effort in -p or the Agent SDK, a project, managed or --settings effortLevel, or a per-model level/autocompact's footer hint to name ←/→, the keys that adjust other ordered values/fast's footer to name Space as the toggle keyPermissionRequest hooks: an agent-type hook no longer runs there, since its answer could never allow or deny the request; it now shows an error pointing to command or http hooksctrl+l / cmd+k in fullscreen mode clearing the transcript view (added in 2.1.260); they redraw the screen again--configure-git--retire-at release losing its finished signal; the runner now briefly waits for the turn to be reported before stopping the sessiongit:// remotes there now need GIT_ALLOW_PROTOCOLgh and GitHub API calls inside a cloud session on a GitHub Enterprise Server repository failing after about eight hours; the token now renews automatically