Claude Code 2.1.238 adds Concise output, idle notices, and safer session messaging

Anthropic’s latest Claude Code release adds a built-in Concise output style and continues a week of improvements to cross-session work, Remote Control, self-hosted runners, and permission feedback. The changelog labels the August 20 update 2.1.238.

Concise output style

Claude Code now includes a Concise output style. Anthropic describes it as leading with the result, skipping preamble and narration, and still doing the work thoroughly. Users can select it under Output style in /config.

The option is useful for terminal workflows where the developer wants the same underlying task execution with less explanatory framing in the visible response. It is a presentation setting, not a separate model or a promise that tool work will be reduced.

One-shot idle notices for cross-session work

The August 19 changelog entry adds notify_when_idle to cross-session SendMessage. A Claude Code session can ask another session on the same machine to send one notice the next time it becomes idle. Anthropic describes the behavior as opt-in, one-shot, and not based on polling; the entry lists macOS and Linux support.

The same week’s fixes improve feedback when cross-session delivery is refused or an inbox drops a message because of a rate limit or a full queue. Instead of reporting silent success, the sending session can now learn that the message was refused or dropped.

Model defaults and Remote Control reliability

Claude Code adds ANTHROPIC_DEFAULT_MODEL for choosing the model new sessions start with. A /model selection can still override it and persist across restarts, unlike ANTHROPIC_MODEL.

The release also improves Remote Control behavior: server-mode sessions apply the same enterprise-gateway availability check as interactive startup, and brief HTTP 403 responses from a network edge, VPN, or proxy can be tolerated for up to three minutes before a persistent block is reported. Remote sessions can also be reused after a crashed process instead of requiring a full claude remote-control restart.

Self-hosted runner and MCP changes

The August 20 entry adds a self-hosted-runner option to defer shutdown for a configured number of minutes, allowing attached sessions to keep serving before the runner parks remaining work and exits. It also adds proxy-authorization command and file options for egress proxies that need a freshly issued header on each connection.

MCP marketplace and helper changes add clearer approval boundaries. Header helpers run only in the documented install or update flow after the command is shown, and project-scoped helpers require the folder’s trust dialog to be accepted. The changelog also notes fixes for long-session memory growth and output styles drifting back to the default voice.

Sources

• Claude Code Docs — official changelog, August 20, 2026 / version 2.1.238: https://code.claude.com/docs/en/changelog
• Claude Code Docs — cross-session messaging: https://code.claude.com/docs/en/cross-session-messaging
• ClaudeDevs on X — official Concise output announcement: https://x.com/ClaudeDevs/status/2090245922685063634