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Claude Code v2.1.63: HTTP Hooks and a Massive Memory Leak Cleanup

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2026年2月28日

#Claude Code #Anthropic #release-notes #HTTP Hooks #memory-leak

Anthropic ships Claude Code v2.1.63 with HTTP hooks for external integrations, new slash commands, and fixes for over a dozen memory leaks that plagued long-running sessions.

Anthropic has released Claude Code v2.1.63, and this one’s worth paying attention to. Alongside a handful of new features — HTTP hooks, bundled slash commands, and cross-worktree config sharing — the release tackles a staggering number of memory leaks that had been quietly eating RAM during long coding sessions.

HTTP Hooks: Webhooks for Claude Code

The headline feature is HTTP hooks. Until now, Claude Code’s hook system was limited to running shell commands. With v2.1.63, hooks can POST JSON to a URL and receive JSON back, opening the door to direct integration with external web services and APIs without the overhead of spawning shell processes.

New Slash Commands: /simplify and /batch

Two new bundled slash commands join the lineup. /simplify does what you’d expect — asks Claude to reduce complexity in selected code. /batch enables grouping multiple operations into a single command, useful for repetitive refactoring tasks.

For developers who work across multiple git worktrees of the same repository, project configs and auto-memory are now shared automatically. No more duplicating .claude/ settings across worktrees.

The Memory Leak Reckoning

The real story of this release is the sheer volume of memory leak fixes. Anthropic’s team clearly went on a hunt, and they found problems everywhere:

Bridge polling loop listener leak
MCP OAuth flow cleanup leak
Hooks configuration menu navigation leak
Interactive permission handler listener leak during auto-approvals
Bash command prefix cache unbounded growth
MCP tool/resource cache leak on server reconnect
WebSocket transport listener leak on reconnect
Git root detection cache unbounded growth in long sessions
JSON parsing cache unbounded growth over time
Teammates retaining all messages after conversation compaction
MCP server fetch caches not cleared on disconnect
Subagent progress payloads retained during context compaction

For anyone running extended Claude Code sessions — and especially those using MCP servers with frequent reconnections or heavy subagent workflows — this release should deliver noticeable improvements in memory consumption.

Other Improvements

MCP OAuth fallback: Manual URL paste when localhost redirect fails
ENABLE_CLAUDEAI_MCP_SERVERS=false: New env var to opt out of claude.ai MCP servers
/model command: Now shows the currently active model in the menu
/copy command: Added “Always copy full response” option
/clear fix: Cached skills are now properly reset
VS Code: Remote sessions appear in conversation history; session rename/remove added
REPL bridge: Fixed race condition causing message ordering issues during initial connection

How to Update

npm install -g @anthropic-ai/claude-code

After v2.1.59’s auto-memory feature and several stability patches, v2.1.63 represents a significant quality-of-life release. The memory leak fixes alone make it a must-upgrade for power users running long sessions.

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