Claude Code v2.1.310 Update: Monitor Tool and Multiple Fixes

Claude Code has released version v2.1.310. This update focuses on stability and cross-platform experience, with the newly introduced Monitor tool and plugin monitoring capabilities being the most noteworthy. Here is a breakdown of the core changes in this update.

Monitor Tool and Monitoring Capabilities Launch

This version adds the Monitor tool and plugin monitors, covering three deployment environments: Bedrock, Vertex, and Foundry. This capability remains available even when telemetry or non-essential traffic is disabled. At the same time, long foreground sleeps are also blocked in these environments, helping to reduce resource usage caused by unnecessary waiting.

Bedrock, Vertex, and Foundry are the managed access channels through which Claude is offered by the three major cloud providers: Amazon Bedrock (AWS), Vertex AI (Google Cloud), and Microsoft Foundry (formerly Azure AI Foundry). Enterprise customers typically call models through these platforms, so their network policies, telemetry toggles, and compliance restrictions are often stricter than those of a direct API connection. The article emphasizes that Monitor remains available when "telemetry or non-essential traffic is disabled," meaning the capability does not depend on sending data back to external endpoints, which is especially critical for regulated industries or network-isolated environments.

Telemetry refers to usage data and performance metrics automatically reported by the client for diagnostic and improvement purposes. Many enterprises disable telemetry in their configurations to meet data compliance requirements, but some features that strongly depend on the telemetry channel will fail as a result. Therefore, "available with telemetry disabled" is an important indicator of whether a monitoring capability can actually be deployed.

Plugin monitors can be understood as mounting monitoring logic into the Claude Code runtime pipeline in the form of plugins, used to observe signals such as tool calls, session state, or resource usage, providing an integration point for future observability capabilities (such as metric collection and anomaly alerting).

Gateway Compatibility and Request Retry Optimization

To address the issue where some gateways and compatible servers reject the effort-2025-11-24 beta value or mid-conversation system messages, Claude Code now automatically retries requests after removing these items, thereby reducing the request failure rate. This change is especially meaningful for users behind proxy gateways.

Beta values (such as effort-2025-11-24) are request header markers in the Anthropic API used to enable experimental features, typically sent with requests in the form of anthropic-beta. Enterprises often deploy proxy gateways in between for authentication, auditing, or traffic shaping, and such gateways often validate request headers against a whitelist, directly rejecting unrecognized beta values. "Mid-conversation system messages" refers to system-role messages inserted during an ongoing conversation, a form that some compatible servers do not support. Claude Code now retries after removing rejected content, which is a "degraded retry" strategy: sacrificing individual experimental features in exchange for request success, significantly reducing the failure rate for users behind gateways.

A Series of Bug Fixes

This update fixes several issues that affect daily use:

• An issue where background cleanup mistakenly deleted recent files (such as pasted images) when cleanupPeriodDays was set to an extremely large value.
• An issue where, when compacting after a "Prompt is too long" error, dense text (such as base64 or SVG) was retained in excessive amounts, causing the next request to still fail.
• An issue where file read permission prompts did not show the location a symbolic link points to.
• An issue where, after long editing sessions, closing the external editor caused the auto-continue timeout for questions to trigger immediately.
• On Windows, an issue where PreToolUse and PermissionRequest hooks allowed tool calls through when Git Bash was missing and the hook command was only a quoted string.

Symbolic links (symlinks) are special files that point to another path. When a permission prompt shows only the link itself and not its actual target, users cannot determine which file they are actually authorizing to read, creating a security risk of misauthorization; after the fix, the prompt displays the location the link points to, making auditing easier.

Git Bash and hooks on Windows: Claude Code's hooks (such as PreToolUse and PermissionRequest) essentially execute external commands. When Git Bash is missing on Windows, command parsing degrades, and if the hook command is only a quoted string, it may be misjudged as "no actual command" and the tool call allowed through directly — this is a permission bypass, making this fix particularly important.

Experience and Performance Improvements

• The auto-mode prompt before the first read of a file outside the working directory is clearer, explaining when blocking the read will cause shell commands to request permission.
• Improved memory usage during compaction of non-interactive sessions (-p, Agent SDK) when transcript files are very large.
• Fixed an issue where images displayed only alt text in tmux with allow-passthrough and focus-events enabled, as well as in full-screen rendering scenarios in kitty, Ghostty, and iTerm2 3.5+.
• On Linux, /sandbox and sandbox startup warnings now clearly point out Ubuntu's AppArmor restrictions on user namespaces and provide instructions on how to lift them.
• In non-interactive sessions, when an MCP tool call times out and the server elicitation goes unanswered, the error message now indicates that Claude did not receive a reply and advises against repeated calls.

Transcript files are record files in which Claude Code saves the complete conversation history, growing continuously as sessions get longer. Non-interactive sessions (-p parameter, Agent SDK) need to load the transcript into memory when compacting history, and very large files can cause memory spikes. This improvement reduces memory usage during compaction, lowering the risk of OOM in long sessions or batch processing scenarios.

Ubuntu's AppArmor restrictions: In recent years, Ubuntu has enabled AppArmor policies by default that restrict non-privileged users from creating user namespaces, a capability that sandboxes (such as bubblewrap) often rely on for isolation. This causes /sandbox startup to fail; the new version clearly indicates this restriction and how to lift it, turning an obscure failure into actionable guidance.

VSCode and Cloud Session Fixes

In the VSCode extension, fixed an issue where pressing Enter on "Send feedback and keep planning" in the plan review card instead approved the plan, and an issue where opening a cloud session from the Web tab of session history and then clicking "Switch branch & continue" produced "Something went wrong."

For cloud sessions, this update adds Claude Code cloud session and Remote Control permissions for Enterprise custom roles, making it easier for owners to control access by role; adds a "Choose file" button to load cloud environment setup scripts from a file; fixes issues where save and archive failures in the cloud environment edit dialog showed no error, and routine API token operation failures showed only a toast; the session startup checklist now displays setup script output in a scrollable box; enabling cloud sessions or Remote Control in admin settings now requires confirmation and lists custom roles that have the permission; and the cloud environment dialog now expands network access, setup scripts, and environment variables by row.

Other Module Fixes

Claude Tag fixed an issue where ! commands (such as !restart, !help) in bold, italic, or strikethrough formatting were treated as regular messages, as well as issues where background refresh failures of the bundle list caused the admin page to be replaced by a load error and the spending limit page incorrectly reported no matching channels while channel names were loading. The Code Review admin section fixed an issue where hidden repositories and toggles disappeared after a repository list refresh failure, and added a retry and a unified "Try again" banner when the initial load fails.

Overall, v2.1.310 is a maintenance update focused mainly on fixes and compatibility, and the addition of the Monitor tool lays the groundwork for future observability capabilities.

Image note: The original material did not provide screenshot information, so no images were inserted into the article.

One-line Summary

Claude Code v2.1.310 adds the Monitor tool and focuses on fixing stability and cross-platform issues.

Paragraph Summary

Claude Code has released v2.1.310, positioned as a maintenance update focused mainly on fixes and compatibility. The most noteworthy change is the addition of the Monitor tool and plugin monitors, covering three deployment environments — Bedrock, Vertex, and Foundry — and remaining available when telemetry is disabled, while also blocking long foreground sleeps. On gateway compatibility, the client now automatically retries after removing rejected effort-2025-11-24 beta values and mid-conversation system messages, reducing failure rates behind proxy gateways. Fixes cover background cleanup mistakenly deleting recent files, dense text still exceeding limits after compaction, symlink permission prompts, questions auto-continuing and timing out immediately after closing the external editor, and hooks allowing calls through when Git Bash is missing on Windows. It also improves memory usage when compacting very large transcripts, image rendering in tmux/kitty/Ghostty/iTerm2, Linux sandbox AppArmor prompts, and VSCode plan review and cloud session permissions and dialogs.