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Claude Code v2.1.288

latestnext 425 entries read Grouped into 350 v2.1.287 → v2.1.288 Mods API: +3 added · 0 removed · 1 changed · 7 docs only Markdown JSON Follow Unofficial

You can now hold project settings changes made from a cloud session until you approve them, by running claude apply-project-settings in that folder. This applies when your computer serves the cloud session. Admins can force unattended serving off through managed settings with unattended_serving_off. Resumed sessions no longer keep the prompt cache warm unless the new resumeTouches setting is on. Claude Code's own stand-in for gh, added last release, can now reach any GitHub Enterprise host when ghesHosts is set to "any". Host apps can block file writes in chosen folders, except inside one declared worktree.

A /restart command that keeps your session is in this build but not switched on yet. It also answers to /update and offers newer versions. A shortcut that answers some artifact edit requests with direct file edits is also off for now. Cloud sessions can hand finished file writes to the next turn's worker, but only once that is switched on remotely. A setup guide feature is wired into the prompt box but does nothing yet.

An oversized reply from an MCP server over HTTP now fails only that request and keeps the connection open. Language server requests now time out instead of waiting forever. Reads and rewrites of a session transcript now wait for each other, so compaction and resume cannot clash. Resumed teammates no longer bring back an agent type that a rule or plugin now blocks. The Read tool instructions no longer include the guidance on PDF page ranges.

Written by our agent from the shipped bundle, not by Anthropic.

Five to try today

Picked from 23 you can use now
  1. claude mcp serve lists agent types and blocks background agents in restricted mode

    claude mcp serve now offers custom subagent types, and new switches can block background-agent launch and remote isolation, used in its http mode

    Sessions & agents
  2. Cloud sessions served by your computer take settings more cautiously

    When your computer serves a cloud session, changed project settings are held back until claude apply-project-settings, and user settings can only tighten

    Sessions & agents
  3. Host apps can fence off folders so file tools write only to a worktree

    Two new environment variables let an embedding app block file writes inside chosen paths, except inside one declared worktree

    Elsewhere
  4. Plugin runtime adds ui.selection and ties network and audio access to a plugin id

    Plugins get a new ui.selection operation, and http.fetch and URL audio playback now use a plugin storage id, with $.audio.play refusing URLs without one

    Extensions
  5. CLAUDE_CODE_DISABLE_STRUCTURED_OUTPUTS turns off structured outputs

    Setting CLAUDE_CODE_DISABLE_STRUCTURED_OUTPUTS stops Claude Code from asking the model for replies in a fixed format

    Elsewhere

Want the reasoning? Read walks the 31 entries that probably matter to you, each one opening to what changed and why.

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29 entries here

What probably matters to you

Anything you can use today, anything that visibly changes, and anything worth poking at. One line each, open for detail.

◌In dev
Nothing to try yet
Useful3 Signal4
Group of 2 Cloud Sessions unclear

Turn handoffs to cloud workers can now carry over pending file writes#

A turn handoff can now carry answered Write calls to a cloud worker, which writes those files into the home folder before the turn continues

Unclear It is not clear how the new worker learns about and receives the carried writes from end to end.

Details 0 0 Feedback
◌In dev
Nothing to try yet
Useful3 Signal4
Group of 2 Compaction unclear

Precomputed compaction summaries are checked for coverage and fit before reuse#

Before reusing a summary prepared in advance, auto-compact now checks it still covers the conversation and fits, and refuses it with a named reason if not

Unclear It is not clear whether preparing summaries in advance runs for anyone, since its setting is only shown when a server-side switch allows it.

Details 0 0 Feedback
+New
Use it now
Useful5 Signal4
Worktrees Notable no docs found unclear

Host apps can fence off folders so file tools write only to a worktree#

Two new environment variables let an embedding app block file writes inside chosen paths, except inside one declared worktree

Unclear Which host application sets these variables is not shown.

Details 0 0 Feedback
CLAUDE_CODE_HOST_WORKTREECLAUDE_CODE_HOST_WORKTREE_FENCE
◌In dev
Nothing to try yet
Useful3 Signal5
Permissions unclear

New hidden switch tied to an "arbiter" permission mode#

Claude Code has a new remotely controlled switch, off unless turned on, with a check for an "arbiter" permission mode beside it

Unclear It is not clear what the switch controls, where the arbiter check is used, or what "arbiter" mode is.

Details 0 0 Feedback
+New
Use it now
Useful4 Signal2
Group of 2 Background Tasks unclear

Fleet view gets find, group jumping and rebindable keys#

The agents fleet view adds find and jump-between-groups actions, and its keys, including rename and set group, can now be rebound

Unclear The default key for agents:setGroup is not listed, so it may no longer be ctrl+e.

Details 0 0 Feedback
+New
Use it now
Useful4 Signal3
Prompt Cache no docs found unclear

New resumeTouches option, off by default#

The activity keep-alive settings now include a resumeTouches option, which is off unless set otherwise

Unclear It is not clear what turning this option on does or where it is set.

Details 0 0 Feedback
resumeTouchestouchIntervalSecondsactivityWindowMinutes
+New
Use it now
Useful5 Signal2
Accessibility Notable no docs found unclear

New settings to hold and rewrite screen-reader announcements#

Two environment variables control holding screen-reader announcements, for up to 10 seconds, and rewriting held ones, which is off by default

Unclear Where these announcements are held, and whether another setting must also be on, is not shown.

Details 0 0 Feedback
CLAUDE_AX_ANNOUNCEMENT_HOLD_MSCLAUDE_AX_REWRITE_HELD_ANNOUNCEMENT
↑Improved
Use it now
Useful3 Signal3
Permissions no docs found unclear

Starting permission mode can now be adopted outside remote sessions#

A session can now take on a starting permission mode it was handed even when it is not a remote session, if an option asks for it

Unclear It is not clear what sets this option or whether a reader can set it.

Details 0 0 Feedback
adoptSeedPermissionMode
+New
Use it now
Useful4 Signal2
Terminal UI unclear

Keyboard shortcut actions to raise or lower effort#

Two new keyboard shortcut actions, chat:increaseEffort and chat:decreaseEffort, step the effort level up or down

Unclear It is not clear whether these actions have keys assigned by default or are held back behind a switch.

Details 0 0 Feedback
+New
Use it now
Useful4 Signal1
Group of 2 Language Servers Notable unclear

Language server requests now time out, with a configurable requestTimeout#

Requests to LSP language servers now give up after 60000 ms by default, which an LSP server's requestTimeout setting can change

Unclear Whether requests already waited 60000 milliseconds before this change, so that the default is unchanged, is not established.

Details 0 0 Feedback
requestTimeout
·Internal
Use it now
Useful3 Signal2
Telemetry no docs found unclear

Diagnostic logs sent to Datadog can be compressed, with a fallback#

Log batches sent to Datadog can now be gzip-compressed, falling back to uncompressed if Datadog refuses one

Unclear Whether compression is on by default when the environment variable is not set is not established.

Details 0 0 Feedback
CLAUDE_CODE_GZIP_DATADOG_LOGS
↑Improved
Use it now
Useful3 Signal1
CLI Commands

claude project purge is now claude purge#

The purge command moved from claude project purge to claude purge; the old name still works but prints a deprecation notice

Details 0 0 Feedback
claude purge
↑Improved
Use it now
Useful3 Signal1
Themes no docs found unclear

New shimmer colour for the auto-accept indicator#

A new light purple theme colour for an auto-accept shimmer effect sits next to the existing auto-accept colour

Unclear It is not clear where the new colour is shown.

Details 0 0 Feedback
autoAcceptShimmer
Were these the right ones to put at the top? 0 answered
Below the fold

Everything else

Smaller changes and internals, grouped as the pipeline found them. Nothing is dropped, it is only further down.

1 entry here

New Featuresopen

15 more of these are in What probably matters to you, above.

+New
You'll notice
Useful3 Signal3
Memory unclear

New confirmation dialog for saving account memory everywhere#

Claude Code now has a confirmation dialog for writing account memory everywhere, alongside its existing account memory permission prompt

Unclear It is not clear when this dialog appears or whether it is switched off unless enabled remotely.

Details 0 0 Feedback
156 entries here

Improvementsopen

8 more of these are in What probably matters to you, above.

↑Improved
You'll notice
Useful3 Signal3
Group of 4 Auth unclear

Login reports when credentials could not be saved and can be skipped#

Login now warns when your credentials could not be saved instead of claiming success, names the storage used, and can let you continue without logging in

Unclear It is not clear where this message appears.

Details 0 0 Feedback
↑Improved
You'll notice
Useful2 Signal3
Group of 4 Background Agents unclear

Background subagents wake more reliably, with results-only wakes#

Idle background subagents now wake for more queued items, can wake only to deliver results, and are dropped after repeated failed resumes

Unclear Part of the new wake-up path may not run yet, and it is not clear what decides the extra cases that trigger a check.

Details 0 0 Feedback
↑Improved
You'll notice
Useful2 Signal3
Group of 2 Models unclear

Model catalog can require a minimum Claude Code version#

The hosted model catalog can now name a minimum Claude Code version that older builds skip, and failed first cloud messages now give a clearer reason

Unclear Whether any model list currently sets a minimum version is not established.

Details 0 0 Feedback
↑Improved
You'll notice
Useful3 Signal3
Artifacts unclear

Claude is told when to publish pages to claude.ai, including unprompted#

The tool that publishes HTML pages to claude.ai now tells Claude to publish when a page beats text or work is for others, even unasked

Unclear It is not clear whether the publishing tool is available to everyone or switched on only for some accounts.

Details 0 0 Feedback
↑Improved
You'll notice
Useful3 Signal2
Group of 2 Prompt Cache no docs found unclear

Prompt cache keepalive for resumed sessions#

Resumed sessions can keep the 1-hour prompt cache warm on a timer, but only when server config sets resumeTouches

Unclear It is not clear where resumeTouches is set or whether you can change it yourself.

Details 0 0 Feedback
resumeTouches
↑Improved
You'll notice
Useful3 Signal3
Artifacts unclear

Small edits to a single-page artifact can be made in one quick step#

Claude Code can now edit an HTML artifact you own in one quick request, and hands the job back when the page is shared, too large or would prompt

Unclear It is not clear what starts this quick edit or whether it is switched on for everyone.

Details 0 0 Feedback
↑Improved
You'll notice
Useful3 Signal3
Memory unclear

Warning when your CLAUDE.md instruction files grow too large#

Claude Code can warn you when the combined size of your CLAUDE.md instruction files goes over the limit, showing the size and the limit

Unclear What the further environment check looks at is not known.

Details 0 0 Feedback
CLAUDE.md
↑Improved
You'll notice
Useful3 Signal3
Auto Update no docs found unclear

Update notice can offer a restart, with its wording set remotely#

The auto-update notice can now show restart wording such as "/restart to apply" or "Restart to update", fetched from a remote configuration

Unclear It is not clear whether /restart exists as a command you can run, or what condition chooses between the two wordings.

Details 0 0 Feedback
/restart
↑Improved
You'll notice
Useful2 Signal3
Input Box unclear

Pasted team setup guides are shown as a placeholder like pasted text#

A pasted team setup guide now appears as a short placeholder, the same way long pasted text does

Unclear Whether the team setup guide feature is available yet, and what triggers it, is not clear.

Details 0 0 Feedback
↑Improved
Under the hood
Useful2 Signal3
Cloud Sessions unclear

Local file attachments are refused in diskless sessions#

In a diskless session, Claude Code now refuses to attach or upload local files and reports an error instead

Unclear It is not clear which sessions count as diskless.

Details 0 0 Feedback
↑Improved
You'll notice
Useful2 Signal3
Database Tools no docs found unclear

Database write results now include warnings and embedded data#

Results from the database write tool now report warnings and embedded data after the usage figures, for single and batch writes

Unclear It is not clear what the embedded part contains, or whether the change is available to everyone.

Details 0 0 Feedback
↑Improved
You'll notice
Useful2 Signal2
Group of 2 Elsewhere unclear

Frontmatter from MCP, memory stores and plugins is read as untrusted#

Skills from MCP servers and memory stores, and plugin agents, now have their frontmatter read with limits and are skipped or refused if it can't be read

Unclear It is not clear what reading a header as untrusted changes beyond skipping skills whose header fails.

Details 0 0 Feedback
↑Improved
Under the hood
Useful2 Signal2
Group of 5 Sessions no docs found unclear

Environment info now covers the GitHub CLI and its stand-in#

Claude's environment details gain a githubCli entry, the model is told when built-in gh goes away, and the gh stand-in can reach any GitHub host

Unclear It is not clear what sets ghesHosts to "any".

Details 0 0 Feedback
ghesHosts
↑Improved
You'll notice
Useful2 Signal2
Group of 2 Structured Outputs unclear

Side queries retry without structured output when a model rejects it#

Side queries now retry without the structured-output format when the API rejects output_config.format, and new helpers recognise PDF and format errors

Unclear It is not clear what check now decides whether the format is requested at first.

Details 0 0 Feedback
output_config.format
↑Improved
You'll notice
Useful2 Signal2
Group of 2 MCP unclear

Headless startup changes how it waits for deferred MCP servers#

Headless sessions can skip waiting for MCP servers the conversation doesn't need, and no longer defer servers added after the first request

Unclear It is not clear which mode or setting turns this skipping on.

Details 0 0 Feedback
↑Improved
You'll notice
Useful2 Signal2
Group of 2 MCP unclear

MCP browser requests now let you confirm when you are done#

When an MCP server asks you to finish something in a browser, the dialog now offers Open in browser, I'm done, continue and Decline

Unclear It is not clear which MCP requests use the new layout and which still use the old two-button one.

Details 0 0 Feedback
↑Improved
You'll notice
Useful2 Signal2
Group of 2 Remote Control unclear

Remote Control bridge tracks environment secret expiry and can renew it ahead of time#

The Remote Control bridge now records when its environment secret expires and can re-register early to renew it; stop messages are reworked

Unclear What starts an early re-registration, and what sets the separate check-in interval, is not established.

Details 0 0 Feedback
↑Improved
You'll notice
Useful3 Signal2
Auto Mode unclear

Auto mode can shorten a long conversation instead of repeatedly blocking actions#

When a conversation is too long for auto mode's safety check, Claude Code can now compact it and tell Claude to retry the action afterwards

Unclear What decides whether Claude Code asks for compaction, rather than only blocking, is not settled.

Details 0 0 Feedback
↑Improved
You'll notice
Useful3 Signal2
Memory unclear

Claude Desktop warns when CLAUDE.md and rules files are too large#

The Code tab in Claude Desktop now gets a warning when your CLAUDE.md and rules files together exceed the recommended size

Unclear The recommended size limit itself is not stated.

Details 0 0 Feedback
CLAUDE.md
↑Improved
You'll notice
Useful3 Signal2
Code Review unclear

Code review can keep every finding or report through a tool#

The code review prompt can now keep every finding with no limit, or have results reported through a tool call

Unclear It is not clear what decides which version or which limit a review uses.

Details 0 0 Feedback
↑Improved
You'll notice
Useful3 Signal2
MCP unclear

MCP step-up sign-in dialog now defaults to on#

The dialog for MCP servers that ask you to sign in again with extra permissions now falls back to on when the server sends no setting

Unclear It is not clear what the second remote switch, now read where the old one was, controls.

Details 0 0 Feedback
↑Improved
You'll notice
Useful3 Signal1
Group of 4 Elsewhere unclear

Updates now detect a missing native binary instead of reporting success#

The updater now checks the installed claude runs, fails with native_binary_missing if it is only a stub, and shows clearer failure hints

Unclear Where this failure category is shown to the person installing is not stated.

Details 0 0 Feedback
↑Improved
You'll notice
Useful3 Signal1
Group of 2 Input Box unclear

Text cleared with Ctrl+C can be brought back with Up#

Clearing the prompt box with Ctrl+C now keeps the text, and pressing Up while the box is empty restores it

Unclear The exact situations in which Ctrl+C keeps the text, and how long it is kept, are not known.

Details 0 0 Feedback
↑Improved
You'll notice
Useful2 Signal2
MCP unclear

Dialogs where an MCP server asks you for input can ask you to confirm you are done#

The dialog an MCP server uses to ask you for input can now be told you will confirm when you are done, and can check whether an answer would be taken

Unclear It is not established whether this dialog is linked to the step-up sign-in setting for MCP servers whose default changed.

Details 0 0 Feedback
↑Improved
You'll notice
Useful2 Signal2
MCP unclear

MCP sign-in now notices when a server asks for more permission#

Claude Code now checks each MCP server sign-in response for a missing-permission answer and returns the server's real response

Unclear It is not shown where the step-up dialog switch is read, so the link between this change and that dialog is unconfirmed.

Details 0 0 Feedback
↑Improved
You'll notice
Useful2 Signal2
Sessions unclear

Remote sessions explain withdrawn permission requests#

Remote sessions can now say a permission request was withdrawn because nobody answered it in time, and a --any-host flag appears

Unclear It is not clear which commands accept --any-host or --gh-standin, or what they do.

Details 0 0 Feedback
↑Improved
You'll notice
Useful2 Signal2
Tool Search unclear

More tools may be held back until Claude searches for them#

Claude Code now defers a second set of tools, keeping their details out until tool search finds them

Unclear It is not clear which tools are on the new list.

Details 0 0 Feedback
↑Improved
You'll notice
Useful2 Signal2
Hooks unclear

Project hooks that changed after approval now ask again in remote sessions#

In remote sessions, a project hook that changed after you approved it is now held until you give permission again

Unclear The exact wording you see when asked again, and whether this is switched on for everyone, is not clear.

Details 0 0 Feedback
↑Improved
You'll notice
Useful2 Signal2
Sessions unclear

Remotely served tool calls now stop when the session stops being served#

Tool calls served to a remote session are cancelled when that session is no longer served, and broken project hooks are tracked

Unclear It is not clear what switches this behaviour on or what its defaults are.

Details 0 0 Feedback
↑Improved
You'll notice
Useful2 Signal2
Plugins no docs found unclear

Plugins lose network access in confined sessions#

Plugins are now refused network access when CLAUDE_CODE_EVAL_CONFINED is set, and a message says the session's credential is withheld

Unclear Which sessions count as being in the mode that gets the credential-withheld message is not known.

Details 0 0 Feedback
CLAUDE_CODE_EVAL_CONFINED
↑Improved
You'll notice
Useful2 Signal2
Compaction unclear

Compaction can reuse a summary it already made#

Claude Code can decide to reuse an earlier compaction summary, and refuses when, for example, the result would not fit

Unclear What triggers this reuse, and whether it is switched on, is not stated.

Details 0 0 Feedback
↑Improved
You'll notice
Useful2 Signal2
Sessions unclear

Resuming a session now checks the saved model before switching to it#

Resuming a session now checks the saved model before using it, and a saved "default" resolves to the current default model

Unclear It is unclear where the logic for restoring a model after a refused launch model is used, so its effect is unknown.

Details 0 0 Feedback
↑Improved
You'll notice
Useful2 Signal2
Subagents unclear

Subagents lose the Agent tool once the nesting limit is reached#

When subagents are nested as deep as allowed, the Agent tool is taken away from the next one, even if its definition asks for it

Unclear The depth limit is not stated, and it is not clear where the record that the tool was withheld shows up.

Details 0 0 Feedback
↑Improved
You'll notice
Useful2 Signal2
Auto Mode no docs found unclear

Auto mode's classifier floor applies even when the classifier cannot run#

Auto mode's classifier floor can now take effect even when the automatic checker cannot run, which it could not before

Unclear It is not clear what the classifier floor does to a tool call when the classifier cannot run.

Details 0 0 Feedback
chromeClassifierFloorEnabled
↑Improved
You'll notice
Useful2 Signal2
Remote Control unclear

Remote Control handles two machines trying to attach to one session#

When two machines try to host the same Remote Control session, one can now follow the newer one or step down

Unclear It is unclear what decides which of these paths runs, or whether this tracking is active.

Details 0 0 Feedback
↑Improved
You'll notice
Useful3 Signal1
Plugins unclear

Plugin detail menu now offers Update now and Uninstall#

The menu for a single plugin now lists Update now and a red Uninstall option, so you can manage the plugin from there

Unclear Some kinds of plugin may not show these options.

Details 0 0 Feedback
↑Improved
You'll notice
Useful3 Signal1
Remote Control unclear

Remote Control renews this computer's credential before it expires#

Remote Control now renews this computer's credential before it expires, instead of only after a connection is rejected

Unclear Renewal depends on an expiry time from the server, and what sets it is not known.

Details 0 0 Feedback
↑Improved
You'll notice
Useful3 Signal1
Plan Mode unclear

Approving a plan now switches Claude Code back to default mode#

Approving Claude's plan to leave plan mode now switches the session to default permission mode, and the mode indicator shows an "on" hint

Unclear It is not clear what the busy state for slash commands changes for you in practice.

Details 0 0 Feedback
↑Improved
You'll notice
Useful2 Signal1
Group of 3 API Errors unclear

API timeouts get their own timedOut cause and are retried#

API timeout errors are now classified as timedOut instead of serverError, and are retried or sent to a fallback model rather than failing

Unclear It is not clear what this handling actually does, for example whether it retries the request or skips a fallback.

Details 0 0 Feedback
↑Improved
You'll notice
Useful2 Signal1
Group of 2 Remote Control unclear

Remote Control placeholder clean-up checks the server before archiving#

Cleanup of unused Remote Control placeholder sessions now keeps connected sessions and checks title, use and server state before archiving

Unclear It is unclear what records that a placeholder session was used.

Details 0 0 Feedback
↑Improved
You'll notice
Useful1 Signal2
Background Tasks unclear

Stopping an unknown task can now name the host tool it needs#

When Claude Code can't find a task you ask it to stop, the error may now name the host tool that owns it

Unclear It is not clear when the host-tool lookup is on or what the "needs" part of the message names.

Details 0 0 Feedback

Continues on page 2 →

Verbatim
Official · Anthropic

Anthropic’s official release notes

Published verbatim by Anthropic for v2.1.288. Text is unmodified from the upstream changelog. Everything else on this page came out of the bundle instead, which is why the two lists don't match.

Of these 89 bullets, 18 name something an entry on this page also names, 29 name something no entry here does, and 42 name nothing specific enough to line up either way. The pairings are made on names both sides wrote down, a flag or a setting or a slash command, so read one as probably the same thing rather than as a fact, and read the middle number as candidates rather than as a miss count.

A model matched these bullets to the GitHub issues they fix, so a link can be wrong.

System prompt

2 of 27 tool descriptions changed. 1 of 25 tool schemas changed. The appended system-reminder blocks moved: 1 line added, 1 line removed.

Claude Code, interactive mode

2 prompt changes in this release could not be quoted from the build, so no entry on this page describes them.

Documentation

What the docs did around this release

725 documentation changes were recorded within 24 hours either side of this release, nearest first. The closest 12 are below. They're here because they happened near this release in time. That's not a claim that this release caused the edit, or that the page documents anything in it.

Switches

Every name in this release

The 63 literal strings found in the bundle, with the number of entries that name each one. Picking one searches for it. A name is here because this build's code mentions it, which is not the same as it working or being finished.

Slash commands

CLI flags

Environment variables

Settings and names in the code

Feedback