[Release] anthropics/claude-code v2.1.81: v2.1.81

Claude Code v2.1.81 introduces the `--bare` flag for scripted calls, adds `--channels` permission relay for mobile approval forwarding, and fixes critical issues with OAuth re-authentication, voice mode reliability, and WebSocket connection handling. The release also improves MCP tool collapsing, plugin freshness tracking, and Remote Control session management while addressing numerous edge cases and race conditions across authentication, terminal UI, and bash command execution.

Key Points

• •Added `--bare` flag for scripted `-p` calls that disables hooks, LSP, plugin sync, and auto-memory; requires explicit API key configuration (OAuth/keychain disabled)
• •Implemented `--channels` permission relay allowing channel servers to forward tool approval prompts to mobile devices for Team/Enterprise orgs
• •Fixed concurrent Claude Code sessions requiring repeated OAuth re-authentication when one session refreshes its token
• •Resolved voice mode failures: fixed silent retry swallowing, improved error messaging, and added WebSocket reconnection recovery
• •Fixed `CLAUDE_CODE_DISABLE_EXPERIMENTAL_BETAS` not suppressing structured-outputs beta header, preventing 400 errors on proxy gateways
• •Improved MCP read/search tool calls to collapse into single summary lines (expandable with Ctrl+O) for cleaner output
• •Enhanced plugin freshness by re-cloning ref-tracked plugins on every load to pick up upstream changes
• •Fixed multiple race conditions: background agent task output hanging, fast Cmd+Tab with paste under tmux, and permission prompts for dashed bash strings
• •Updated MCP OAuth to support Client ID Metadata Document (CIMD/SEP-991) for servers without Dynamic Client Registration
• •Disabled line-by-line response streaming on Windows/WSL due to rendering issues; improved bash mode discoverability with `!` suggestions

Workflow Diagram

Concepts

Artifacts (2)

# Key Configuration Changes

## New Flags
- `--bare`: Scripted calls without hooks, LSP, plugin sync; requires ANTHROPIC_API_KEY or apiKeyHelper
- `--channels`: Permission relay for mobile device approval forwarding
- `--settings`: Pass settings including apiKeyHelper for bare mode

## Environment Variables
- `ANTHROPIC_API_KEY`: Required for --bare flag when OAuth/keychain disabled
- `CLAUDE_CODE_DISABLE_EXPERIMENTAL_BETAS`: Now properly suppresses structured-outputs beta header

## Settings
- `showClearContextOnPlanAccept`: Set to true to restore clear context option in plan mode (hidden by default)

## Platform-Specific
- Windows/WSL: Line-by-line response streaming disabled
- Git Bash: Fixed PATH inheritance for Bash tool

## Critical Fixes
1. OAuth Re-authentication: Multiple concurrent sessions no longer require repeated auth
2. Voice Mode WebSocket: Auto-recovery when server silently drops connection
3. Voice Mode Errors: Actual error messages shown instead of generic network warnings
4. Proxy Gateway Compatibility: EXPERIMENTAL_BETAS flag now properly suppresses beta headers

## Race Conditions Resolved
- Background agent task output hanging between polling intervals
- Fast Cmd+Tab + paste beating clipboard copy under tmux
- Plugin hooks blocking prompt submission when directory deleted mid-session

## UI/UX Improvements
- Terminal tab titles auto-update with session descriptions
- Remote Control sessions show derived titles instead of generic labels
- Session titles refresh after third message
- Invisible hook attachments no longer inflate message counts

## MCP & Plugin Enhancements
- Read/search tool calls collapse into single summary lines
- Ref-tracked plugins re-clone on every load for upstream changes
- MCP OAuth now supports CIMD/SEP-991 for servers without Dynamic Client Registration