Claude Code 2.1.89 Ships Headless Hook System with Defer Permissions and Named Subagent Typeahead
GitHub / Anthropic·medium signal
Anthropic released Claude Code 2.1.89 on April 1 with significant agent infrastructure improvements: PreToolUse hooks can now return 'defer' to pause headless sessions mid-execution and resume with re-evaluation, a new PermissionDenied hook fires after auto-mode denials with retry capability, and named subagents appear in @-mention typeahead. MCP_CONNECTION_NONBLOCKING=true skips MCP wait entirely in pipeline mode, and server connections are bounded at 5s.