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Claude Code 2.1.63 adds slash commands and HTTP hooks; ships memory leak fixes
Claude Code · releasefeaturebugfixperformance · github.com ↗

New Features

Claude Code 2.1.63 adds two new bundled slash commands: /simplify for streamlining code or logic, and /batch for handling batch operations. The release also introduces HTTP hooks, enabling developers to POST JSON to external URLs and receive JSON responses, extending Claude Code's integration capabilities beyond traditional shell commands.

The /copy command now includes an "Always copy full response" option to skip the code block picker on subsequent commands, improving workflow efficiency. The /model command has been enhanced to display the currently active model in the slash command menu for better visibility.

Stability and Performance Improvements

This release is primarily focused on stability, addressing 12+ memory leaks that accumulated across long-running sessions. Key fixes include:

  • Session management leaks: Git root detection caches that grew unbounded, JSON parsing caches with unreleased memory, and message retention in long-running subagent sessions
  • MCP integration leaks: WebSocket listener leaks on transport reconnect, MCP tool/resource cache leaks on server reconnect, and fetch cache clearing on disconnect
  • Infrastructure improvements: Fixed IDE host IP detection cache incorrectly sharing results across ports, listener leaks in bridge polling and OAuth flows, and race conditions in the REPL bridge message ordering

Memory usage has been optimized in multi-agent sessions by stripping heavy progress message payloads during context compaction.

Configuration and Integration

  • Added ENABLE_CLAUDEAI_MCP_SERVERS=false environment variable to opt out from making claude.ai MCP servers available
  • Project configs and auto memory are now shared across git worktrees of the same repository
  • VSCode: Added session rename and remove actions to the sessions list; fixed remote sessions not appearing in conversation history
  • Fixed a critical bug where long sessions could accumulate stale cached skills that persisted across /clear commands

Other Improvements

  • Local slash command output (like /cost) now appears as system messages instead of user-sent messages in the UI
  • Manual URL paste fallback added during MCP OAuth authentication when automatic localhost redirect doesn't work
  • Fixed file count cache to respect glob ignore patterns