Claude-Code v2.1.78: Plugin State, Streaming Responses, and Critical Fixes

What's New in Claude-Code v2.1.78

Anthropic released Claude-Code v2.1.78 with significant improvements to plugin management, response handling, and security. This update addresses several critical bugs and adds practical features for developers using AI coding agents.

Key Additions

• StopFailure hook event: Fires when a turn ends due to API errors like rate limits or authentication failures
• ${CLAUDE_PLUGIN_DATA} variable: Provides plugin persistent state that survives plugin updates; /plugin uninstall now prompts before deleting this data
• Frontmatter support for plugin-shipped agents: Added effort, maxTurns, and disallowedTools parameters
• Line-by-line response streaming: Response text now streams as it's generated
• Terminal notification improvements: iTerm2/Kitty/Ghostty popups and progress bars now reach the outer terminal when running inside tmux with set -g allow-passthrough on
• ANTHROPIC_CUSTOM_MODEL_OPTION environment variable: Adds a custom entry to the /model picker, with optional _NAME and _DESCRIPTION suffixed variables for display

Critical Fixes

• Fixed infinite loop: API errors triggering stop hooks no longer re-feed blocking errors to the model
• Fixed permission bypass: deny: ["mcp__servername"] permission rules now properly remove MCP server tools before sending to the model
• Fixed sandbox security: sandbox.enabled: true with missing dependencies now shows a visible startup warning instead of silently disabling
• Fixed protected directory writes: .git, .claude, and other protected directories are no longer writable without a prompt in bypassPermissions mode
• Fixed conversation history truncation: cc log and --resume no longer silently truncate large sessions (>5 MB) that used subagents

Other Improvements

• Fixed git issues: git log HEAD no longer fails with "ambiguous argument" inside sandboxed Bash on Linux, and stub files no longer pollute git status
• Fixed sandbox paths: sandbox.filesystem.allowWrite now works with absolute paths (previously required // prefix)
• Fixed platform-specific display: /sandbox Dependencies tab now shows macOS-specific info on macOS instead of Linux prerequisites
• Fixed keybindings: ctrl+u in normal mode now performs readline kill-line instead of scrolling (ctrl+u/ctrl+d half-page scroll moved to transcript mode only)
• Fixed voice mode: Modifier-combo push-to-talk keybindings (e.g., ctrl+k) now activate immediately instead of requiring a hold; WSL2 with WSLg (Windows 11) now works, while WSL1/Win10 users get a clear error
• Fixed environment variables: ANTHROPIC_BETAS is no longer silently ignored when using Haiku models
• Fixed prompt concatenation: Queued prompts no longer concatenate without a newline separator
• Improved performance: Better memory usage and startup time when resuming large sessions
• Fixed VS Code issues: Brief flash of login screen when opening sidebar while authenticated; model dropdown no longer offers 1M context Opus variant to subscribers with unknown plan tiers

This release primarily benefits developers who use Claude-Code plugins, work with large conversation histories, or need more reliable sandbox and permission controls.