Claude Code 2.1.271

September 14, 2026

This release introduces a new fast mode for remote sessions, allowing quicker interaction where permitted by your organization. Enhanced sandboxing for Bash, PowerShell, and Monitor commands now offers per-command host access for improved security and control. Other additions include mouse support in the configuration panel and flexible agent settings. Significant stability improvements address issues with organization policy refreshing, git command failures in sandboxed environments, and tool list updates. Users will also notice faster terminal rendering, more informative spinner statuses, and robust handling of dynamic workflows and artifact management across the platform.

Added

Added fast mode in Claude Code Remote sessions (cloud and self-hosted runners): the host's fast-mode setting or `/fast` typed in the session applies where your organization allows it
Added mouse support to the `/config` panel in fullscreen mode: the wheel scrolls the settings list, a click on a setting's value changes it, and the row under the pointer is highlighted
Added `claude self-hosted-runner --drain-marker-file <path>`: when that file exists at a SIGTERM drain, the runner reports its exit to the server as a host drain (telemetry only)
Added per-command `allowed_domains` to Bash, PowerShell and Monitor in auto mode with sandboxing: the hosts a command needs are reviewed with it and opened for it alone; other hosts are refused
Added `omitClaudeMd` to agent frontmatter and `--agents` JSON, letting custom and plugin subagents run without user, project and local CLAUDE.md files; managed policy files still load
Added `--accept-command <sha256>` to `claude plugin install` and `claude plugin update` to accept exactly the command a previous `--json` run displayed, instead of `-y`
Added support for a `multiplier` above 1, up to 10, in the `modelPricing` managed setting and the Claude apps gateway `pricing` block, for marked-up internal chargeback rates
Added a spinner tip pointing Bedrock, Vertex AI, Foundry and LLM gateway users to the Claude desktop app; the claude.ai desktop app tip now suggests `/desktop`, which offers to download the app
Added an Attach Open File setting that, when turned off, stops the open file from being added to messages; selected text is still attached

Improved

Improved terminal rendering performance: large diffs and long transcripts render faster, with fewer slow frames
Improved startup time slightly by skipping a redundant validation of built-in model data on every launch
Improved hook feedback: while a SessionStart, UserPromptSubmit, PreToolUse or SessionEnd hook runs, the spinner says so with elapsed time, and Esc cancels a prompt waiting on a SessionStart hook
Improved the spinner status during long thinking: it now reads "deep in thought" after 45s, and shows "picking the thought back up" while recovering from the output-token limit
Improved dynamic workflows to pause when you hit your usage limit and continue automatically when it resets, instead of dropping the affected agents
Improved Remote Control to leave fewer empty sessions on claude.ai when setup fails on a flaky network
Improved the Claude in Chrome message in cloud sessions when the browser can't be reached: it now says the computer may be asleep before it suggests an install
Improved `claude mcp serve`: a running tool call now sends a progress update every 30 seconds, so clients show it is still running and idle timeouts don't abort a long command that prints nothing
Improved Foundry and Claude Platform on AWS sessions: an `alwaysLoad` MCP server that finishes connecting mid-conversation is usable on the next turn without a tool-search round trip
Improved Markdown files published as artifacts: they now render as styled document pages (title header, document typography, syntax-highlighted code)
Improved Artifact tool publish errors: a publish with no file now says to write the page to a file first, and an unsupported file type is reported before a missing favicon
Improved the Artifact tool's error when a page declares a capability its contract version lacks: it now lists every supported capability and notes when a newer contract version has it
Improved artifact watching: a session can now watch up to 10 published artifacts at once for republishes made elsewhere, up from 5
Improved PDF @-mentions to say "page count unknown" instead of a page count guessed from the file size when pdfinfo cannot count the pages
Improved `/mobile` to show a single QR code for claude.ai/mobile, which opens the right app store for your phone
Improved the Hooks dialog: a save refused because of the settings file itself now opens a popup with an "Open settings file" button and the reason behind "Copy error"

Changed

Changed auto mode so that a skill's or slash command's inline `!` shell commands follow default-mode permission rules instead of the classifier; a command no rule decides runs as a reviewed tool call
Changed auto mode so a subagent reports back to its caller through a dedicated hand-back call that the safety classifier reviews, instead of its last message being reviewed after the fact
Changed Monitor watches to always have a deadline (at most 30 minutes; 10 in single-prompt `-p` runs) and notify Claude to re-arm, replacing the no-timeout `persistent` option
Changed the IDE selection indicator in the prompt to a `[⧉ …]` pill that wraps with the text instead of squeezing multi-line prompts; delete it with Backspace to leave the selection out
Changed the default dynamic workflow size to small on Pro plans and lowered the medium size guideline from 15 to 10 agents
Changed Claude apps gateway, Bedrock, Vertex AI, and Foundry sessions so that they no longer refresh a leftover claude.ai login that the session does not use
Updated the bundled `claude-api` skill to enable `eager_input_streaming` on streaming custom tools, and to start deliverable-shaped Managed Agents work with `user.define_outcome`
Changed the on state of toggle switches from Claude orange to the editor theme's button color
[Claude Code on the web] Changed the Routines page on claude.ai/code to a new layout with Yours and Templates tabs and two-column routine cards that show run status, and removed its calendar view
[Claude Code on the web] Added a Custom network access option to the Cloud environments editor in admin settings, with the same allowed-domains list the environment dialog on claude.ai/code offers
[Claude Code on the web] Improved the Cloud environments admin page: it shows the default environment for Claude Tag and Claude Code, with a link to change it, and marks the recommended kind to create
[Claude Tag] Improved the Environment picker in Claude Tag admin settings: options are labeled Anthropic-hosted or self-hosted, with links to edit that environment or create one

Fixed

Fixed a cached organization policy being reused after switching accounts, organizations, or API keys, and the policy not refreshing until the hourly check when the credential changes mid-session
Fixed the tool and command lists not updating when the organization policy finishes loading after startup or changes mid-session
Fixed an enterprise `managed-mcp.json` that can't be read or parsed being ignored: it now keeps exclusive MCP control (user, project and plugin servers don't load) and warns at startup
Fixed org policy being fetched through, and rejected by, third-party local proxies set via `ANTHROPIC_UNIX_SOCKET`; they are again treated like other custom gateways, including for Remote Control
Fixed cloud sessions rejecting every subagent tool call ("updatedInput … failed schema validation") when a workflow or agent approval was applied after the session's worker restarted
Fixed `/fast off` answering "Fast mode unavailable" instead of turning fast mode off when the organization has fast mode disabled
Fixed sessions started with `CLAUDE_CODE_SKIP_FAST_MODE_ORG_CHECK` re-sending fast requests every turn after the API rejected fast mode; the rejection now stands and its reason is shown
Fixed fast mode under `CLAUDE_CODE_RETRY_WATCHDOG` failing the turn on a usage-credits limit, or retrying an overload at fast speed, instead of falling back to standard speed
Fixed Bash permission checks missing the file that `fmt`, `column` and similar commands read when it follows an option the checker doesn't recognize
Fixed Bash permission checks skipping files a wildcard expands to when the wildcard sits in a command's pattern or option value (for example `grep -v dir/* file`)
Fixed Bash permission checks so that shell variable declaration flags cannot misrepresent the command being run
Fixed Bash commands with two directory changes, a subshell, or a `cd`+`git` chain skipping the prompt under `permissions.blockReadsOutsideWorkingDirectories` in bypass and auto mode
Fixed a stale `.git/config.lock` breaking `git checkout -b`, `git push -u` and `git config` for the rest of a session after a sandboxed command failed to start (Linux)
Fixed settings file changes made outside the session going unnoticed on macOS machines whose system file-event service is saturated; the watcher now falls back to polling
Fixed resumed `claude -p` sessions whose tools all come from MCP servers failing with "At least one tool must have defer_loading=false"
Fixed turns failing with "API returned an empty or malformed response" when an LLM gateway returns the non-streaming reply as `text/plain`
Fixed sustained high CPU usage and repeated tool-list requests when an MCP server sends `list_changed` notifications in a tight loop
Fixed MCP OAuth mishandling client registrations: denying consent forced a new one, one for another redirect URI was reused, and a concurrent write could delete a valid one or keep a mismatched one
Fixed tool search returning no match when Claude selects an MCP tool by its bare name instead of its full `mcp__server__tool` name
Fixed Ctrl+O cancelling pending MCP server reconnects, and `/mcp` sent from Remote Control failing while the transcript view is open
Fixed the Claude in Chrome prompt telling the model to load tools through ToolSearch when ToolSearch is unavailable
Fixed cross-session messages held by the receiving session's permission-mode policy leaving no trace: headless senders now get a delivery notice, and `SendMessage` results no longer imply it was read
Fixed Claude starting a second copy of a background command (such as a watch task or dev server) that was still running after the conversation was compacted
Fixed `/model` warning about losing the conversation cache when switching back to the model the conversation actually ran on
Fixed `/reload-skills` reporting a skill count that disagreed with the slash menu after `/cd`
Fixed `/resume` and `/continue` showing only 1-2 sessions in fullscreen mode on short terminals
Fixed `/resume` and `/teleport` keeping the previous conversation's file-read tracking, so Claude could edit files the resumed conversation had never read
Fixed `--resume` dropping the 1M context window (`[1m]`) when the resumed session's model family differs from the configured default model
Fixed artifacts attached with `/artifacts` disappearing from the session after `--resume`
Fixed background sessions (`claude --bg`, `claude agents`) not watching the artifacts they publish for republishes made elsewhere
Fixed custom agents, slash commands and output styles beyond the first not loading from a virtual drive that reports inode 0, such as an encrypted vault mounted as a Windows drive
Fixed self-hosted runner sessions silently losing all host config (settings, skills, plugins, MCP servers) when the host config directory exceeds 64 MiB; added `--host-config-snapshot disk|memory`
Fixed skills synced from claude.ai staying on disk indefinitely after signing out; copies not refreshed within `cleanupPeriodDays` now move to the recoverable trash at the next launch
Fixed spinner tips suggesting commands that aren't available for your account type or are disabled in your session
Fixed the `/add-dir` path input: the left and right arrow keys now move the cursor, and Enter adds only the typed path instead of also adding the highlighted completion
Fixed text fields outside the main prompt moving a leading `!` to the end of what you typed (`!foo` came out as `foo!`)
Fixed the interactive `/hooks` menu crashing when a hook matcher is named after an inherited object property such as `__proto__` or `constructor`
Fixed a fullscreen rendering glitch where text kept a stale background color after the box around it lost its background
Fixed Delete in st and Alt+arrow keys in rxvt-unicode not working in attached background sessions
Fixed the terminal's replies to capability queries (`^[[?1;2c`) appearing at the shell prompt or in an editor when Claude Code exits, is suspended, or opens an editor right after starting
Fixed the Hooks and Permission rules dialogs reporting a save that landed as failed, and the Hooks dialog going blank under a plugin-only policy lock or showing color codes in save errors
Fixed Hooks dialog saves: no duplicate hook on replace, a header name retyped in other capitals keeps its secret, and settings.local.json is gitignored before the save returns
Fixed session history showing only the current session when the workspace is on a Windows mapped network drive or SUBST drive
Fixed the session list's Active filter hiding open idle sessions when Open is also checked in the filter menu
Fixed a new chat switching back to the previous chat when the session list refreshed
Fixed open tabs and the side bar keeping the old config folder until a window reload after `CLAUDE_CONFIG_DIR` changed in the `environmentVariables` setting
Fixed console windows flashing on Windows when the extension runs background commands such as git, ripgrep, and the sign-in status check
Fixed the prompt cache clock's hover text appearing only after a delay, and the auto-compact icon showing the browser's own tooltip beside its popup
[Claude Code on the web] Fixed a cloud session sometimes taking about ten minutes to respond after its process exited while the session still looked live; sending a message now restarts it right away
[Claude Tag] Fixed Claude in a channel where it stays active losing its working context about once an hour when the conversation is mostly in threads; thread activity now keeps it from being reset
[Claude Tag] Fixed a thread that asked Claude to watch a pull request no longer hearing about CI failures, comments and reviews after Claude was restarted in that thread
[Claude Tag] Fixed deleting the first message of a thread Claude had already replied in not ending Claude's work there; it now stops, as it did when a message with no replies was deleted
[Claude Tag] Fixed Claude holding back a post because of an earlier instruction addressed to a different bot or assistant; only instructions addressed to Claude bind it, and it asks when unsure
[Claude Tag] Fixed the reply-mode card Claude posts on joining a busy channel saying it "sees a lot of automated posts" when the channel is only chatty or large; the card now names the real reason
[Code Review] Fixed a pull request in a repository reviewed once per PR sometimes getting no review when a commit arrived while its review was waiting to start; it now reviews the requested commit
[Code Review] Fixed Code Review occasionally posting the same findings two or three times when GitHub reported an error for a review it had in fact created
[Code Review] Fixed follow-up reviews re-posting a security finding a person had already resolved when a later push moved the lines it was anchored to
[Code Review] Fixed reopening a finished /ultrareview cloud session in the Claude app starting the whole review over again unprompted
Windows: Fixed PowerShell commands failing with "Exit code 1" and no output when the session's temp output path reaches 260 characters