SIGNAL
Tracking the global AI frontier — labs · research · agents · policy
Frontier Signal
Agents

Claude Code v2.1.221

Claude Code v2.1.221
Primary source github.com ↗

Published August 4, 2026 · Category: AI Agents

Overview

What's changed

  • [VSCode] Added Focus view: a chat-menu toggle that hides tool activity behind an expandable per-turn summary with a live running-tool indicator, toggled with Ctrl+Alt+F or the "Claude Code: Toggle Focus view" command
  • Added mode: "mask" for sandbox credential files on Linux and WSL — sandboxed commands read a sentinel copy (the whole file, or just the spans captured by an extract regex) while the sandbox proxy substitutes the real value on egress; on macOS file masking falls back to deny
  • Added warnings to claude plugin validate when a marketplace or plugin name would be rejected by Claude Desktop's managed marketplace sync
  • Added a prompt-audit subcommand to the claude-api skill for auditing prompts and tool descriptions for patterns written for older models
  • Fixed a Bash tool permission-check bypass where zsh could execute hidden commands in [[ ]] regex conditionals; affected commands now prompt for permission
  • Fixed PowerShell permission checks mishandling paths containing quote characters on Windows; such paths now prompt for approval
  • Fixed the thinking toggle having no effect for the rest of a session that started with thinking off; disabling an MCP server mid-connect no longer silently reverts
  • Fixed MCP servers from --mcp-config not being connected before the first turn in print mode (-p), which made the model emit tool calls as literal text
  • Fixed @-mentioned files being silently dropped when pressing Esc to retract a prompt and resubmitting it
  • Fixed a crash when preparing API requests for SDK MCP tools named after built-in object properties such as constructor
  • Fixed WebSearch failing with a 400 error at effort xhigh/max when thinking is disabled
  • Fixed sandboxed large uploads failing with TLS errors through the sandbox proxy
  • Fixed Team and Enterprise spend-limit message incorrectly blaming the org's monthly limit instead of your individual spend limit
  • Fixed Bedrock authentication with AWS SSO named profiles failing in desktop-managed sessions on Windows machines that set a stray HOME environment variable
  • Fixed CLAUDE_CODE_RESUME_INTERRUPTED_TURN=0 not disabling interrupted-turn auto-resume; falsy values are now honored
  • Fixed a rare wake-from-sleep race where two Claude Code processes could both refresh the same MCP connector or WIF OAuth token at once, forcing re-authentication
  • Fixed renaming a session from Claude Code Desktop or claude.ai not updating the CLI's session name; session names from every rename surface are now sanitized
  • Fixed plugin- and org-delivered skills named after terminal-only built-ins (e.g. /help, /feedback) being un-invocable in non-interactive sessions
  • Fixed the "Plugins changed" notification lingering after plugins were reloaded instead of clearing
  • Fixed Vim mode: the yank register now survives dialogs, history search, and the transcript view instead of being silently emptied
  • Fixed Vim mode: undoing back to an empty prompt now arms the "press ← again" confirm before returning to the agent view
  • Improved tool search on Google Vertex AI: re-enabled for Claude 4.5-generation and newer models
  • Improved auto mode: permission checks for parallel tool calls are now cache-efficient, and switching modes while a check is pending reliably prompts instead of applying the stale result
  • Reduced prompt-cache costs for auto-mode permission checks by reusing the cached conversation prefix across decisions
  • Improved Stats panel to count cache tokens in its token totals, with a breakdown by input, output, cache read, and cache write
  • Improved /ultrareview error messages when a repo shares no history with its base: a checkout with no branches is now refused up front with advice to create one, and refusal hints no longer suggest git fetch --unshallow on clones that are already complete
  • Improved Windows startup: process creation times are now read via a native kernel32 call instead of spawning PowerShell, so endpoint security tools that gate powershell.exe no longer prompt
  • Changed background sessions to commit and push to preserve work, open a draft PR only when the task calls for one, follow your CLAUDE.md git instructions, and always end by reporting where the work lives
  • Changed /plugin install to refresh a stale marketplace catalog and retry before reporting a plugin not found
  • Changed plugins installed from /plugin to activate immediately when safe, instead of always requiring /reload-plugins
  • Changed plugins to accept "." as a skills path, and the root-level SKILL.md validation error now suggests using the plugin root
  • Changed /status to show the session kind: interactive, or a background job that is attached or unattended
  • Changed emoji autocomplete to accept common alternate shortcodes like :thumbsup:, :thumbsdown:, and :love:
  • Changed sessions forked with /fork to create a new worktree of their own instead of working in the original session's checkout
  • Changed Claude in Chrome to close the browser tabs it opens once it no longer needs them
  • Changed fast mode to report on the stream when usage credits run out mid-session, instead of failing silently
  • Changed Monitor: a watch that exits without producing any output now says so instead of reporting "stream ended"
  • Changed the Gateway model field validation: non-string values are rejected with a 400 instead of being forwarded
  • Removed the repeated "Permission mode changed while the auto-mode classifier call was queued" notice from approval prompts

Source

Originally published at github.com.

Related Articles

F
Frontier Signal Desk

Frontier Signal tracks the global AI frontier — labs, research, agents, creation tools and real-world practice — straight from primary sources. Tip the desk: editorial@news.tunx.ai

Email the desk →
From our network: explore the AI assistant platform behind this site. Visit tunx.ai →
Note: This story is aggregated and summarized from the primary source linked above; the original publisher retains all rights. Details may evolve after publication — always confirm against the source. Nothing here is professional, legal or investment advice.

Related Stories

More from Agents →