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DisclaimerUnofficial, and not affiliated with Anthropic. Nearly all of this is read straight out of what ships: npm bundles, captured prompts, published docs. Anthropic's own notes go in verbatim, marked as theirs. The rest is my reading, and every entry carries the strings behind it. If one looks wrong, vote it down and say why.

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Claude Code v2.1.41

19 entries read diff v2.1.40 → v2.1.41 Markdown

This release introduces comprehensive memory guidance (rolling out via feature flag), MCP session recovery with automatic tool retries, and improved device file handling in the Read tool. WebSocket connections now handle permanent close codes and include Bun-specific ping support. The admin eligibility API for extra usage requests was also added.

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13 entries

Changesopen

Enhanced Memory System Guidance [Gradual Rollout]#

What

Detailed instructions for Claude on when and how to use the persistent memory directory.

Details

The new guidance includes:

  • When to access memories: When memories are relevant, user refers to prior work, or explicitly asks to recall
  • When to save memories: Project context, user preferences, debugging insights, architectural decisions
  • What to save: Patterns, conventions, user workflow preferences, recurring problem solutions
  • What NOT to save: Ephemeral task details, duplicate information contradicting CLAUDE.md
  • Memory hygiene: Remove outdated info, organize by topic not chronologically, use separate topic files
Status

Controlled by tengu_mulberry_fog feature flag (defaults to disabled)

Evidence

Memory guidance system (search for "You MUST access memories when")

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

Related

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

MCP Session Recovery with Automatic Retry#

What

When an MCP server session expires, Claude Code now automatically reconnects and retries the failed tool call.

Details
  • Detects session expiration via 404 status with error code -32001 or connection close
  • Clears connection cache and triggers re-initialization
  • Automatically retries the tool call that failed due to session expiration
  • New McpSessionExpiredError error type for proper error handling
Evidence

MCP session recovery (search for "MCP session expired during tool call" and "Retrying tool")

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

Device File Read Blocking#

What

The Read tool now blocks attempts to read device files that would block or produce infinite output.

Details

Blocked device files include:

  • /dev/zero, /dev/random, /dev/urandom, /dev/full
  • /dev/stdin, /dev/tty, /dev/console
  • /dev/stdout, /dev/stderr, /dev/fd/0, /dev/fd/1, /dev/fd/2

Error message: "Cannot read '[path]': this device file would block or produce infinite output."

Evidence

Device file blocklist (search for "device file would block")

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

AWS Authentication Permission Type#

What

New permission category for AWS authentication operations displayed in the permission UI.

Evidence

AWS Auth permission (search for "AWS Authentication")

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

StopTaskError for Task Termination#

What

New error type for cleanly stopping running tasks with proper error code handling.

Evidence

Task stop error (search for "StopTaskError")

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

Related

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

FileTooLargeError for Read Tool#

What

New error type thrown when attempting to read files exceeding the maximum size limit.

Evidence

File size error (search for "FileTooLargeError")

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

Related

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

Admin Eligibility API for Extra Usage#

What

New API endpoint to check eligibility for extra usage requests in team/enterprise contexts.

Evidence

Admin eligibility endpoint (search for "admin_requests/eligibility")

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

WebSocket Connection Handling#

  • Permanent close detection: WebSocket connections now recognize permanent close codes and avoid unnecessary reconnection attempts
  • Bun ping support: Added specific ping handling for Bun runtime WebSocket connections
  • Sessions WebSocket: Similar permanent close handling for session WebSocket connections
Evidence

WebSocket improvements (search for "WebSocketTransport: Permanent close code" and "Sent ping (Bun)")

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

Related

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

Image Dimension Error Handling#

Added specific error handling for images exceeding the 2000px dimension limit in many-image requests. The error message now provides actionable guidance:

  • In interactive mode: "Run /compact to remove old images from context, or start a new session"
  • In non-interactive mode: "Start a new session with fewer images"
Evidence

Image dimension handling (search for "image dimensions exceed")

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

Related

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

Shell Snapshot Recovery#

Added automatic recreation of shell snapshots when the snapshot file goes missing, improving resilience of the shell execution environment.

Evidence

Shell snapshot recovery (search for "Failed to recreate shell snapshot")

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

Pre-flight Check Message Generalization#

The pre-flight check warning now uses a generic tool name placeholder instead of hardcoded "[BashTool]", making it applicable to multiple tool types. The emoji prefix was also removed for cleaner output.

Evidence

Pre-flight message (search for "Pre-flight check is taking longer")

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

Streaming Fallback Error Logging#

Added explicit error logging when streaming fails and non-streaming fallback is disabled, controlled by tengu_disable_streaming_to_non_streaming_fallback feature flag.

Evidence

Streaming fallback (search for "non-streaming fallback disabled")

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

Error Message Terminology Update#

  • Changed "Failed to read bash history" to "Failed to read shell history" (more accurate for multi-shell support)

Related

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

1 entry

Bug Fixesopen

#

  • Removed obsolete ignorePatterns migration code and related error handling (search for "Failed to migrate ignorePatterns" in v2.1.40 - absent in v2.1.41)
  • Removed "No editor available" error path - editor handling appears to have been restructured
  • Removed task stop status error message ("is not running, so cannot be stopped") - logic was revised
1 entry

Internal Changes (Not User-Facing)open

#

  • Removed "Layout engine: yoga" debug logging
  • Code path changes for task stopping don't affect user behavior
  • Minor text adjustments in Plan agent phase descriptions
Verbatim
Official · Anthropic

Anthropic’s official release notes

Published verbatim by Anthropic for v2.1.41. 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.

  • Added guard against launching Claude Code inside another Claude Code session
  • Fixed Agent Teams using wrong model identifier for Bedrock, Vertex, and Foundry customers
  • Fixed a crash when MCP tools return image content during streaming
  • Fixed /resume session previews showing raw XML tags instead of readable command names
  • Improved model error messages for Bedrock/Vertex/Foundry users with fallback suggestions
  • Fixed plugin browse showing misleading "Space to Toggle" hint for already-installed plugins
  • Fixed hook blocking errors (exit code 2) not showing stderr to the user
  • Added speed attribute to OTel events and trace spans for fast mode visibility
  • Added claude auth login, claude auth status, and claude auth logout CLI subcommands
  • Added Windows ARM64 (win32-arm64) native binary support
  • Improved /rename to auto-generate session name from conversation context when called without arguments
  • Improved narrow terminal layout for prompt footer
  • Fixed file resolution failing for @-mentions with anchor fragments (e.g., @README.md#installation)
  • Fixed FileReadTool blocking the process on FIFOs, /dev/stdin, and large files
  • Fixed background task notifications not being delivered in streaming Agent SDK mode
  • Fixed cursor jumping to end on each keystroke in classifier rule input
  • Fixed markdown link display text being dropped for raw URL
  • Fixed auto-compact failure error notifications being shown to users
  • Fixed permission wait time being included in subagent elapsed time display
  • Fixed proactive ticks firing while in plan mode
  • Fixed clear stale permission rules when settings change on disk
  • Fixed hook blocking errors showing stderr content in UI
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