Claude Code v2.1.219: Claude Opus 5 Is Now the Default Opus, with a 1M Context Window!

Hi, it's Shiichan! There's a new Claude Code release, and this time there's a genuinely big headline, so I'm excited to share it with you!

Claude Code Release github.com

What was announced?

Claude Code Release published the latest version of the Claude Code CLI, v2.1.219. The biggest news this time is that a new model, Claude Opus 5 (claude-opus-5), has been added and is now the default Opus model! It supports a 1M context window, and fast mode is priced at $10/$50 per Mtok. This is the release where the Opus generation finally turns over.

The story so far

Until now, Claude Code defaulted to Opus 4.7 or Opus 4.8 as its Opus model. In the /model picker, the row that merged the different Opus versions just showed "Opus" plainly, making it hard to tell at a glance whether 1M context was supported. Fast mode also covered Opus 4.7 at the time.

What changes

With Claude Opus 5 as the default, you can now use the latest Opus model right away without any special configuration. The 1M context window makes it easier to work through large codebases and long conversations in one go, and the fast mode pricing of $10/$50 per Mtok is spelled out clearly, so you can reason about cost as you choose between modes.

The /model picker display was also cleaned up: the merged Opus row now reads "Opus (1M context)". Fast mode eligibility was revisited too — Opus 4.7 was removed from fast mode, and /fast now applies to Opus 5 and Opus 4.8.

Dive Deep

Beyond the model change, this release brings a lot of developer-experience, security, and reliability improvements. Here's a rundown.

Security and permissions

• Added sandbox.network.strictAllowlist, which denies non-allowlisted hosts for sandboxed commands without prompting
• Fixed a permission you approved while a self-hosted runner was restarting being dropped when the session resumed, so the approved action now actually runs
• Added structured failure categories to self-hosted runner spawn and session failures, so hook errors, runner crashes, and config errors can be told apart

Developer workflow

• Added a DirectoryAdded hook that fires after /add-dir or the SDK register_repo_root control request registers a new working directory mid-session
• Added mcp_server_errors to the headless stream-json init event, listing --mcp-config entries skipped by config validation; terminal runs now print a startup warning too
• Added the workflowSizeGuideline settings key, so the advisory Dynamic workflow size guideline can be set from any settings file (the /config row hides while one is set)
• Changed dynamic workflows to default to a medium size guideline (aim for fewer than 15 agents); you can pick another size, or unrestricted, via Dynamic workflow size in /config
• Added nested subagent forwarding in stream-json: with --forward-subagent-text set, subagents spawned at depth-2+ now appear, keyed by their spawning Agent's tool_use id
• 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

Bug fixes and other improvements

• Fixed claude -p text output dropping the answer already produced when a turn dies on a mid-stream API error
• Added HTTP status and error text to claude mcp list and /mcp when a server fails to connect, plus a warning for MCP config values with hidden leading or trailing whitespace
• Fixed the Fable model row showing "Requires usage credits" for plans that include it, caused by a stale cache baking in the label
• Fixed a SIGTERM arriving while a self-hosted runner was starting up leaving a stale active row until the lease expired; it now deregisters cleanly
• Fixed copy-on-select inside GNU screen printing base64 into the terminal instead of copying the selection
• Fixed Remote Control clients keeping a stale fast-mode status after a model switch, reconnect, or failed org check
• Fixed CLAUDE_CODE_GIT_BASH_PATH on Windows exiting or being used as bash when the path isn't a bash/sh binary; it's now ignored with a warning
• Fixed Vim mode: pressing ← on an empty prompt in NORMAL mode now returns to the agent view, not just from INSERT mode
• Fixed screen-reader mode rewriting the entire input line on every keystroke instead of echoing only the typed character

Wrap-up

• The headline of Claude Code v2.1.219 is Claude Opus 5 becoming the default Opus model, with a 1M context window and fast mode priced at $10/$50 per Mtok
• The /model picker display was cleaned up, and fast mode eligibility was revisited (Opus 4.7 dropped, Opus 5 and Opus 4.8 now covered)
• Sandbox and security settings got stronger too, with the new sandbox.network.strictAllowlist option
• Plenty of small workflow features landed, like the DirectoryAdded hook and deeper nested subagent spawning/forwarding
• Numerous quality-of-life bug fixes shipped too, including the claude -p answer-loss fix and clearer MCP connection errors
• If you've been waiting to try the latest Opus model, or you work with large codebases in Claude Code, this is an update worth checking out!