Claude-Code v2.1.51: Security fixes, performance improvements, and new remote control feature

What's new in Claude-Code v2.1.51

Anthropics has released Claude-Code v2.1.51 with security fixes, performance improvements, and new features for developers using AI coding agents.

Key changes and fixes

• New remote control feature: Added claude remote-control subcommand for external builds, enabling local environment serving for all users.
• Plugin marketplace improvements: Updated default git timeout from 30s to 120s and added CLAUDE_CODE_PLUGIN_GIT_TIMEOUT_MS environment variable for configuration. Added support for custom npm registries and specific version pinning when installing plugins from npm sources.
• BashTool performance: Now skips login shell (-l flag) by default when a shell snapshot is available, improving command execution performance. Previously required setting CLAUDE_BASH_NO_LOGIN=true.
• Security fixes: Fixed issue where statusLine and fileSuggestion hook commands could execute without workspace trust acceptance in interactive mode. Fixed HTTP hooks interpolating arbitrary environment variables from header values - env var interpolation now requires explicit allowedEnvVars list in hook configuration.
• Context management: Tool results larger than 50K characters are now persisted to disk (previously 100K), reducing context window usage and improving conversation longevity.
• API stability: Fixed bug where duplicate control_response messages (e.g., from WebSocket reconnects) could cause API 400 errors by pushing duplicate assistant messages into conversation.
• SDK improvements: Added CLAUDE_CODE_ACCOUNT_UUID, CLAUDE_CODE_USER_EMAIL, and CLAUDE_CODE_ORGANIZATION_UUID environment variables for SDK callers to provide account info synchronously, eliminating race condition where early telemetry events lacked account metadata.
• Plugin compatibility: Fixed slash command autocomplete crashing when a plugin's SKILL.md description is a YAML array or other non-string type.
• Network security: HTTP hooks now routed through sandbox network proxy when sandboxing is enabled, enforcing domain allowlist. HTTP hooks not supported for SessionStart/Setup events.
• UI improvements: The /model picker now shows human-readable labels (e.g., "Sonnet 4.5") instead of raw model IDs for pinned model versions, with upgrade hint when newer version available.