Release archive

Claude Code v2.1.219: Claude Opus 5 Becomes the Default Opus Model, Nested Subagents, and a Strict Sandbox Allowlist

Claude Code v2.1.219 adds Claude Opus 5 as the default Opus model, lets subagents nest up to depth 3, adds a strict sandbox network allowlist and a DirectoryAdded hook, and defaults workflows to a medium size.

• 10 min read • By ClaudeWorld

Claude Code v2.1.219 adds Claude Opus 5 (claude-opus-5) and makes it the default Opus model. The release also lets subagents spawn nested subagents by default, adds new settings and a hook for sandbox networking, working directories, and dynamic workflow sizing, and improves MCP connection diagnostics. Fixes cover headless output, the /model picker, Remote Control, Windows, and screen-reader mode.

What’s New

Claude Opus 5 Is the Default Opus Model

Claude Opus 5 (claude-opus-5) is added and is now the default Opus model, with 1M context and fast mode at $10/$50 per Mtok. Opus 4.7 has been removed from fast mode, so /fast now applies to Opus 5 and Opus 4.8. The claude-api skill also defaults to Claude Opus 5, with a migration path from Opus 4.8.

Nested Subagents up to Depth 3

Subagents can now spawn nested subagents up to depth 3 by default (previously 1); set CLAUDE_CODE_MAX_SUBAGENT_SPAWN_DEPTH=1 to disable nesting. In stream-json output, subagents spawned at depth 2 or deeper now appear when --forward-subagent-text is set, keyed by the tool_use id of the Agent call that spawned them.

Strict Network Allowlist for the Sandbox

The new sandbox.network.strictAllowlist setting denies non-allowlisted hosts for sandboxed commands without prompting.

New DirectoryAdded Hook

A DirectoryAdded hook now fires after /add-dir or the SDK register_repo_root control request registers a new working directory mid-session.

Dynamic Workflow Size Guideline

Dynamic workflows now default to a medium size guideline (aim for fewer than 15 agents); you can pick another size, or unrestricted, with Dynamic workflow size in /config. The new workflowSizeGuideline settings key lets you set this advisory guideline from any settings file, and the /config row is hidden while one does. The running-workflow status line now shows the current default workflow size, with a pointer to /config for changing it.

Clearer MCP Connection Diagnostics

When a server fails to connect, claude mcp list and /mcp now show the HTTP status and error text, and Claude Code warns about MCP config values with hidden leading or trailing whitespace. The headless stream-json init event also gains mcp_server_errors, which lists --mcp-config entries skipped by config validation, and terminal runs print a startup warning.

Fixes and Improvements

Headless

  • claude -p text output no longer drops the answer already produced when a turn dies on a mid-stream API error.

Model picker

  • The /model picker now shows the merged Opus row as “Opus (1M context)” instead of plain “Opus”.
  • The /model picker now highlights only the newest model’s name, so the highlight marks the new release rather than an arbitrary subset of the list.
  • The Fable model row no longer shows “Requires usage credits” for plans that include it when a stale cache had baked the label in.

Remote Control

  • Remote Control clients no longer keep a stale fast-mode status after a model switch, reconnect, or failed org check.
  • The “Remote Control is only available via api.anthropic.com” error now names the specific setting that caused it.

MCP

  • Managed MCP allowlist/denylist ${VAR} entries now resolve from the startup environment and managed-settings env instead of settings-file env.

Windows

  • A CLAUDE_CODE_GIT_BASH_PATH that isn’t a bash/sh binary no longer causes an exit or gets used as bash; it’s now ignored with a warning.

Terminal and input

  • Copy-on-select inside GNU screen now copies the selection instead of printing base64 into the terminal.
  • In Vim mode, pressing ← on an empty prompt now returns to the agent view from NORMAL mode, not just INSERT.
  • Screen-reader mode now echoes only the typed character instead of rewriting the entire input line on every keystroke.

Teleport

  • claude --teleport now shows which repo your current checkout points at when it doesn’t match the session’s repo.

How to Update

  1. Check your installed version: claude --version
  2. Update in place: claude update
  3. Subagents can now spawn nested subagents up to depth 3 by default; set CLAUDE_CODE_MAX_SUBAGENT_SPAWN_DEPTH=1 if you want to disable nesting.