Claude Code v2.1.70 Released - API Error Fixes and Performance Improvements

Anthropic released Claude Code v2.1.70 on March 6, 2026. This version brings numerous bug fixes and improvements focused on API error corrections, Windows/WSL environment enhancements, and performance optimizations.

Key Changes

API and Communication Fixes

Third-Party Gateway Compatibility: Fixed API 400 errors when using the ANTHROPIC_BASE_URL environment variable with third-party gateways. Tool search now correctly detects proxy endpoints and disables tool_reference blocks.

Bedrock Inference Profile Support: Fixed “This model does not support the effort parameter” errors when using custom Bedrock inference profiles with non-standard Claude naming patterns.

Empty Response After ToolSearch: Fixed issue where empty model responses were returned immediately after ToolSearch. The server was rendering tool schemas with system-prompt-style tags at the prompt tail, causing models to stop early.

Windows/WSL Improvements

Clipboard Corruption Fix: Fixed clipboard corrupting non-ASCII text (CJK, emoji) on Windows/WSL by using PowerShell’s Set-Clipboard cmdlet with proper UTF-8 encoding.

SSH Enter Key Behavior: Fixed Enter inserting a newline instead of submitting when typing over slow SSH connections.

Voice Mode Windows Compatibility: Fixed Voice Mode failing on Windows native binary with “native audio module could not be loaded” error.

VS Code Startup Issue: Fixed extra VS Code windows opening at startup on Windows when running from the VS Code integrated terminal.

Performance Optimizations

Memory Reduction: Reduced startup memory by approximately 426KB for users without custom CA certificates.

Remote Control Polling Optimization: Reduced Remote Control polling rate from every 1-2 seconds to once per 10 minutes while connected, cutting server load by approximately 300x. Reconnection remains unaffected.

UI Re-render Reduction: Reduced prompt input re-renders during turns by approximately 74%, improving responsiveness.

VS Code Extension New Features

Session List in Activity Bar: Added spark icon in VS Code activity bar that lists all Claude Code sessions, with sessions opening as full editors.

Plan View Enhancement: Added full markdown document view for plans in VS Code with support for adding comments to provide feedback.

MCP Server Management Dialog: Added native MCP server management dialog - use /mcp in the chat panel to enable/disable servers, reconnect, and manage OAuth authentication without switching to the terminal.

Additional Fixes

• Fixed prompt-cache bust when an MCP server with instructions connects after the first turn
• Fixed push-to-talk not activating on session start
• Fixed markdown links containing #NNN incorrectly pointing to the current repository
• Fixed /security-review command failing with “unknown option merge-base” on older git versions
• Added ways to reset /color command back to default
• Fixed various plugin display issues

Summary

v2.1.70 is a robustness and performance-focused release. The update includes improved compatibility with third-party API gateways, various Windows/WSL environment fixes, and optimizations for memory and network usage that enhance the everyday development experience.