[Release] anthropics/claude-code v2.1.86: v2.1.86

Claude Code v2.1.86 is a maintenance release focused on stability, performance, and bug fixes. Key improvements include session tracking via headers, VCS exclusion enhancements, fixes for file operations outside project root, memory/performance optimizations, and corrections to UI interactions and plugin handling. The release also improves token efficiency through prompt caching and reduced overhead in file mentions.

Key Points

• •Added `X-Claude-Code-Session-Id` header for proxy session aggregation without body parsing
• •Extended VCS exclusion lists to include `.jj` (Jujutsu) and `.sl` (Sapling) metadata directories
• •Fixed `--resume` failures on pre-v2.1.85 sessions with tool_use/tool_result block mismatches
• •Resolved Write/Edit/Read operations failing on files outside project root when conditional skills/rules are active
• •Eliminated unnecessary config disk writes on every skill invocation to prevent performance degradation and Windows corruption
• •Fixed out-of-memory crashes when using `/feedback` on long sessions with large transcripts
• •Corrected `--bare` mode dropping MCP tools and silently discarding mid-turn messages
• •Improved token efficiency by removing JSON-escaping from raw file content and deduplicating unchanged re-reads
• •Enhanced prompt cache hit rates for Bedrock/Vertex/Foundry by removing dynamic content from tool descriptions
• •Fixed multiple UI/UX issues: OAuth URL copying, masked input leaking, scroll following, plugin uninstall dialogs, and statusline model display

Workflow Diagram

Concepts