Copilot Chat v0.43: MCP Insiders & Claude 4.6 Defaults

TL;DR

• MCP Insiders mode now configurable via githubMcpServer.channel setting
• Claude 4.6 now uses optimized Anthropic prompts by default
• New isSystemInitiated flag and fetchedValue concept for better session tracking

New

• MCP Insiders channel setting — githubMcpServer.channel lets you opt into MCP Insiders mode for early feature access
• System-initiated sessions — isSystemInitiated flag added to distinguish system-triggered interactions from user-initiated ones
• Fetched value concept — new abstraction for handling cached or retrieved data in chat sessions

Improved

• Claude 4.6 prompts — optimized Anthropic prompts are now the default for Claude 4.6 models, improving response quality
• Codebase index terminology — UI labels and terms aligned across the new codebase indexing system
• ChatSessionCustomizationProvider — implementation improvements for better session customization
• Context keys — sessions now properly update context keys for improved state management
• API updates — copilot-api updated to send event_content for better telemetry

Changed

• Documentation structure — docs/prompts.md moved to scoped .instructions.md file for better organization

Update via: code --install-extension GitHub.Copilot-Chat or check for updates in VS Code Extensions.

Source: Copilot Chat