Claude Code v2.1.108 / Changelog

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22 entries

Changesopen

JavaScript REPL Tool #

What

A new built-in tool that lets Claude execute JavaScript code in a persistent VM context with programmatic access to Claude Code tools (Read, Write, Edit, Glob, Grep, Bash).

Usage: Claude can now run JavaScript directly to perform file operations, chain tool calls, and compute results. Variables persist across multiple REPL invocations within the same conversation.

Details

Supports top-level await for async operations
State persists across calls — variables defined in one REPL call remain accessible in subsequent calls
Provides registerTool(), unregisterTool(), listTools(), and getTool() for dynamic tool management
Includes a haiku(prompt, schema?) function for lightweight model sampling
Includes shQuote(s) for safe shell string quoting
import/require are not available (VM context is sealed); use the built-in tool functions for file and shell operations
REPL VM state is cleared on /compact — a notification informs you: "Your REPL VM state has been cleared as part of this compaction"
Includes a replay mechanism for validating REPL execution determinism across compaction boundaries

Evidence

REPL tool registration with "Execute JavaScript code with access to Claude Code tools" description (search for "Execute JavaScript")

Strings lifted out of the shipped bundle, so the claim above can be checked against them.

REPL Replay and Drift Detection #

What

Infrastructure for replaying REPL code blocks after compaction to validate that execution produces consistent results.

Details

Extracts code blocks and tool calls from conversation history for replay
Caches tool call results to replay against
Detects nondeterminism: "likely nondeterminism (Date.now, Math.random) took a different branch"
Throws ReplayCacheExhausted when replayed code makes more tool calls than the original
Reports replay status: "N blocks replayed cleanly"

Evidence

Replay infrastructure (search for "REPL replay" and "ReplayCacheExhausted")

Strings lifted out of the shipped bundle, so the claim above can be checked against them.

Other releases about the same thing. Found by shared names or similar wording; neither means one caused the other.

v2.1.248 Clearer error when a replayed REPL run outruns its cached tool calls

Usage Analysis Dashboard (Birch Compass) [Gradual Rollout]#

Feature flag

tengu_birch_compass On for this account, and not off by default

The flag server returned on for the one account this site reads, and nothing in this release compiles it off by default. The compiled default is shown below, and says which it is when we cannot read one: a fifth of gates compile in a string or a number rather than on or off, and most published releases have no gate table behind them at all. No client can see what the server returns for your account.

This account: on · anonymous baseline: off · compiled default in v2.1.108: no gate table built for this version

These values were read against a different version of Claude Code, so treat them as the nearest reading available instead of one taken on this release.

Read once, for one account on one subscription tier, against v2.1.108. It isn't a statement about your account. What a flag value here can and cannot tell you

What

A new settings panel that analyzes your local sessions and shows what's contributing to your rate limit usage, with actionable recommendations.

Details

Available to Pro and Max subscribers
Shows approximate usage breakdown based on local sessions (does not include other devices or claude.ai)
Tracks five cost behavior categories:
Cache misses: "X% of your usage hit a >100k-token cache miss" — recommendation: /compact before stepping away
Long context: "X% of your usage was at >150k context" — recommendation: /compact mid-task, /clear when switching
Subagent-heavy sessions: "X% of your usage came from subagent-heavy sessions" — recommendation: configure cheaper models for simpler subagents
High parallelism: "X% of your usage was while 4+ sessions ran in parallel" — recommendation: queue sessions for more even usage
Long-running sessions: "X% of your usage came from sessions active for 8+ hours" — recommendation: ensure continuous usage is intentional
Toggle between 24-hour and 7-day views with d and w keyboard shortcuts
Notes: "these are independent characteristics of your usage, not a breakdown"
Warns about oversized session files (>200MB) that would skew analysis

Evidence

Feature gated by tengu_birch_compass flag (search for "tengu_birch_compass" and "What's contributing to your limits usage")

Strings lifted out of the shipped bundle, so the claim above can be checked against them.

Model Switch Confirmation Dialog #

What

A new confirmation dialog warns you when switching models mid-conversation that the cache will be invalidated.

Details

Dialog title: "Switch model?"
Message: "This conversation is cached for the current model. Switching to [model] means the full history gets re-read on your next message."
Subtitle: "Your next response will be slower and use more tokens"
Options: "Yes, switch to [model]" or "No, go back"
Only shown when the conversation has cached content for the current model

Evidence

Model switch confirmation (search for "Switch model?" and "This conversation is cached")

Strings lifted out of the shipped bundle, so the claim above can be checked against them.

Fuzzy "Did You Mean?" Suggestions #

What

When you mistype a slash command or skill name, Claude Code now suggests the closest match.

Details

For slash commands: Unknown command: /stauts. Did you mean /status?
For skills: Unknown skill: comit. Did you mean commit?
Uses fuzzy string matching to find the best candidate from available commands and skills
Tracks suggestion availability for analytics

Evidence

Fuzzy matcher for commands and skills (search for "Did you mean /" and "Did you mean ")

Strings lifted out of the shipped bundle, so the claim above can be checked against them.

Other releases about the same thing. Found by shared names or similar wording; neither means one caused the other.

Command vs Skill Disambiguation #

What

When the model tries to invoke a built-in CLI command as a skill, it now receives a clear error explaining the distinction.

Details

Error message: "[name] is a [type] command, not a skill. Ask the user to run /[name] themselves — it cannot be invoked via the [tool] tool."
Prevents confusion between built-in slash commands and skill invocations

Evidence

Disambiguation error message (search for "command, not a skill")

Strings lifted out of the shipped bundle, so the claim above can be checked against them.

MCP Server Auto-Reconnection with Backoff #

What

Failed remote MCP servers now automatically reconnect using exponential backoff instead of staying disconnected.

Details

Logs: [MCP] Retry: N failed remote server(s) after Xms backoff
Stops retrying when all servers reconnect: [MCP] Retry: all remote servers connected, stopping
Reports persistent failures: remote server(s) still failed after all retries:

Evidence

MCP reconnection logic (search for "[MCP] Retry" and "failed remote server")

Strings lifted out of the shipped bundle, so the claim above can be checked against them.

Permission Rule Wildcard Syntax Changed from `:` to #

The wildcard syntax for permission rules has changed from colon-asterisk to space-asterisk. For example:

Old: Bash(git:), Bash(npm run:)
New: Bash(git ), Bash(npm run )

This affects settings files, autocomplete suggestions, onboarding examples, and documentation. The old : syntax continues to be recognized alongside the new syntax for backward compatibility.

Evidence

Permission rule syntax change (search for "Bash(git )" and "Bash(npm )")

Strings lifted out of the shipped bundle, so the claim above can be checked against them.

`/clear` Command Description Updated #

The /clear command description has been updated from "Clear conversation history and free up context" to "Start fresh: discard the current conversation and context" for clearer communication.

Evidence

Clear command description (search for "Start fresh: discard the current conversation and context")

Strings lifted out of the shipped bundle, so the claim above can be checked against them.

Other releases about the same thing. Found by shared names or similar wording; neither means one caused the other.

v2.1.111 /clear Command Description Clarified

`/rewind` Gains `undo` Alias #

The /rewind command (also aliased as /checkpoint) now also responds to /undo, making it more discoverable.

Evidence

Undo alias addition (search for "undo" near "checkpoint")

Strings lifted out of the shipped bundle, so the claim above can be checked against them.

Other releases about the same thing. Found by shared names or similar wording; neither means one caused the other.

v2.1.105 /proactive Alias for /loop

Improved Language Orthographic Correctness #

When Claude responds in non-English languages, it now receives explicit instructions to maintain full orthographic correctness, including all required diacritical marks, accents, and special characters. For example, it will no longer substitute "nao" for "não" or "fur" for "für".

Evidence

Orthographic instruction (search for "orthographic" and "diacritical marks")

Strings lifted out of the shipped bundle, so the claim above can be checked against them.

Enhanced Rate Limit and Server Error Messages #

Rate limit and server error messages now include dynamic status information and direct users to the updated status page at status.claude.com (changed from status.anthropic.com).

Details

429 errors now show: "Request rejected (429)" with "Server is temporarily limiting requests (not your usage limit)"
Status URL changed to status.claude.com
Error guidance suggests: "this may be a temporary capacity issue — check status.claude.com"

Evidence

Status URL change (search for "status.claude.com")

Strings lifted out of the shipped bundle, so the claim above can be checked against them.

Improved Sleep/Blocking Guidance #

The guidance for sleep commands and blocking behavior has been substantially rewritten to emphasize Monitor as the preferred alternative.

Details

Old: sleep N as first command with N ≥ 2 is blocked with brief explanation
New: "Long leading sleep commands are blocked. To poll until a condition is met, use Monitor with an until-loop (e.g. until <check>; do sleep 2; done)"
Additional guidance: "Do not chain shorter sleeps to work around the block"
General sleep advice simplified from "keep the duration short (1-5 seconds)" to "keep the duration short"

Evidence

Blocking guidance improvements (search for "Long leading" and "until-loop")

Strings lifted out of the shipped bundle, so the claim above can be checked against them.

Paste Line Break Normalization #

Multiline paste operations now normalize Windows (CRLF) and classic Mac (CR) line endings to Unix (LF) format, preventing issues with mixed line endings in pasted content.

Evidence

Paste normalization (search for "\\r\\n|\\r" in paste handler)

Strings lifted out of the shipped bundle, so the claim above can be checked against them.

Enhanced BOM Handling in File Reads #

File reading now properly handles UTF-8 Byte Order Marks with improved byte count accounting and comprehensive line ending normalization after BOM removal.

Evidence

BOM detection (search for "65279")

Strings lifted out of the shipped bundle, so the claim above can be checked against them.

Unified Status Icon Component #

Success checkmarks (✓), warning icons, and error indicators throughout the CLI have been replaced with a consistent component-based icon system (N4 component), improving visual consistency across status messages, plugin marketplace results, GitHub Actions workflow confirmations, and iTerm2 setup output.

Evidence

45+ instances of the new component replacing text-based icons (search for status: "success" near N4)

Strings lifted out of the shipped bundle, so the claim above can be checked against them.

Plugin Version Resolution Tracking #

Plugin installations now track a resolvedVersion field that records the tag-derived semver version resolved during installation. This improves version verification and deduplication, especially when upstream plugins forget to bump their plugin.json version.

Details

Description: "Tag-derived semver this install resolved to (when fetched via a version constraint). Used by verifyAndDemote in preference to manifest.version"
Plugin cache is invalidated when resolved version changes

Evidence

Plugin version tracking (search for "resolvedVersion")

Strings lifted out of the shipped bundle, so the claim above can be checked against them.

ExitWorktree and EnterWorktree Subagent Validation #

Both ExitWorktree and EnterWorktree now validate that they are not being called from a subagent with a cwd override (e.g., isolation: "worktree" or explicit cwd). This prevents subagents from mutating the parent session's working directory.

Details

Error: "ExitWorktree cannot be called from a subagent with a cwd override — it would mutate the parent session's process-wide working directory."
Directs subagents to use Bash with cd for directory changes

Evidence

Worktree validation (search for "ExitWorktree cannot be called from a subagent")

Strings lifted out of the shipped bundle, so the claim above can be checked against them.

Ultrareview Cloud Launch Flow #

Ultrareview has been updated with a clearer cloud launch confirmation flow.

Details

Now prompts: "Run ultrareview in the cloud?" with estimated time "~10–20 min"
Requires Claude.ai authentication: "Ultrareview requires a Claude.ai account. Run /login to authenticate."
Unavailable during essential-traffic-only mode
Description updated: "Finds and verifies bugs in your branch using a multi-agent review fleet"
REPL tool execution is blocked during ultrareview with access validation

Evidence

Ultrareview flow (search for "Run ultrareview in the cloud?" and "ultrareview-launch")

Strings lifted out of the shipped bundle, so the claim above can be checked against them.

Settings Schema Refactored to Feature Gates #

The monolithic settings schema has been refactored into a modular feature gate system. Features like autoMode, deepLink, voice, assistant, and briefView are now individually defined with their own buildGate(), shape(), and permissionsShape() methods, making the settings system more maintainable and enabling conditional feature compilation.

Evidence

Feature gate definitions (search for "autoMode" near "buildGate")

Strings lifted out of the shipped bundle, so the claim above can be checked against them.

Headless Plugin Installation Progress Callbacks #

Plugin installations via the SDK now support progress callbacks, enabling SDK consumers to track installation stages (started, completed, per-marketplace installed/failed).

Evidence

Progress callback (search for "Headless plugin installation progress")

Strings lifted out of the shipped bundle, so the claim above can be checked against them.

REPL Blocked by PreToolUse Hook #

REPL tool execution now respects PreToolUse hooks, showing a clear "Blocked by PreToolUse hook" message when execution is blocked by a hook.

Evidence

Hook blocking message (search for "Blocked by PreToolUse hook")

Strings lifted out of the shipped bundle, so the claim above can be checked against them.

4 entries

Bug Fixesopen

#

Fixed paste handling to normalize CRLF and CR line endings to LF in multiline mode, preventing mixed line endings from confusing editors (search for "\\r\\n|\\r/g")
Fixed attribution snapshot handling to clear the map before storing new snapshots, preventing stale data accumulation (search for "D.clear()")
Fixed dependency version resolution to check both resolvedVersion and manifest version for more accurate plugin deduplication (search for "resolvedVersion")
Fixed ANSI escape sequence parsing to correctly handle CSI sequences, OSC sequences, and other terminal control codes (search for "Tq4")
Fixed a variable reference bug in a slice operation where the wrong variable was being used (search for "O6.slice(1)")
Improved validation of at-mentions to require content presence alongside title checks, preventing empty mentions from being processed (search for "contentLength")
Fixed React component state management by correcting dependency arrays and initial state values (search for "lzA")
Improved skill source filtering logic to correctly include builtin sources instead of excluding them (search for "q.source !== 'builtin'")

Birch Compass Session Dashboard [Gradual Rollout]#

Feature flag

tengu_birch_compass On for this account, and not off by default

This account: on · anonymous baseline: off · compiled default in v2.1.108: no gate table built for this version

These values were read against a different version of Claude Code, so treat them as the nearest reading available instead of one taken on this release.

Read once, for one account on one subscription tier, against v2.1.108. It isn't a statement about your account. What a flag value here can and cannot tell you

What

While the dashboard infrastructure is fully built, it is gated behind the tengu_birch_compass feature flag with a default of false, meaning it is not yet available to all users.

Status

Feature-flagged with tengu_birch_compass (default: disabled)

Details

Full UI, cost analysis engine, and 5 behavior categories are implemented
Requires Pro or Max subscription even when enabled
Keyboard shortcuts (d/w) for period switching are wired up
Session scanning and file size validation are complete

Evidence

Feature gated with default false (search for tengu_birch_compass — b8("tengu_birch_compass", !1))

Strings lifted out of the shipped bundle, so the claim above can be checked against them.

Coach Mode [In Development]#

What

A new coachMode configuration option has been added to the settings schema and tracked configuration attributes, but its behavioral implementation is not yet visible.

Status

Infrastructure only — configuration plumbing exists but no observable behavioral changes

Details

Added to tracked configuration attributes alongside existing settings
No user-facing documentation or tips found for this feature yet

Evidence

Configuration property (search for "coachMode")

Strings lifted out of the shipped bundle, so the claim above can be checked against them.

Assistant Feature Gate [In Development]#

What

The feature gate system includes an assistant feature with buildGate: () => !1 (always false), indicating planned but disabled functionality.

Status

Disabled — build gate returns false, shape returns empty object

Details

Included in the feature gate list alongside autoMode, deepLink, voice, and briefView
Shape returns Md5 (an empty object), indicating the settings schema is not yet defined

Evidence

Assistant gate disabled (search for assistant near buildGate — returns !1)

Strings lifted out of the shipped bundle, so the claim above can be checked against them.

1 entry

Notesopen

#

The permission rule wildcard syntax change from : to is the most impactful change for existing users. If you have custom permission rules in your settings files using the old syntax (e.g., Bash(git:)), the old format continues to work but new autocomplete suggestions and documentation now use the space-asterisk format (e.g., Bash(git )). Consider updating your rules to the new syntax for consistency.

The removal of the bundled Chalk template library and HTML5 tokenizer (parse5) from the CLI reduces the package size. These were replaced by lighter-weight alternatives or removed where unused.

Claude Code v2.1.108

Changesopen

JavaScript REPL Tool #

REPL Replay and Drift Detection #

Related

Usage Analysis Dashboard (Birch Compass) [Gradual Rollout]#

Model Switch Confirmation Dialog #

Fuzzy "Did You Mean?" Suggestions #

Related

Command vs Skill Disambiguation #

MCP Server Auto-Reconnection with Backoff #

Permission Rule Wildcard Syntax Changed from `:` to #

`/clear` Command Description Updated #

Related

`/rewind` Gains `undo` Alias #

Related

Improved Language Orthographic Correctness #

Enhanced Rate Limit and Server Error Messages #

Improved Sleep/Blocking Guidance #

Paste Line Break Normalization #

Enhanced BOM Handling in File Reads #

Unified Status Icon Component #

Plugin Version Resolution Tracking #

ExitWorktree and EnterWorktree Subagent Validation #

Ultrareview Cloud Launch Flow #

Settings Schema Refactored to Feature Gates #

Headless Plugin Installation Progress Callbacks #

REPL Blocked by PreToolUse Hook #

Bug Fixesopen

#

Birch Compass Session Dashboard [Gradual Rollout]#

Coach Mode [In Development]#

Assistant Feature Gate [In Development]#

Notesopen

#

Anthropic’s official release notes