Add MCP servers to Claude Desktop with one-click .mcpb extensions or by editing claude_desktop_config.json (Settings > Developer > Edit Config), then restart.
Claude.ai chat on paid plans gets a 1M token context window with Opus 5.5, Sonnet 5.5, Haiku 5.5, and Fable 5.1. Use Projects and memory to keep it focused.
Codex context window: GPT-6 Astra, GPT-6.1 Sol, and GPT-6 Luna list 1.05M tokens in the API. Check your Codex limit with /status and free space with /compact.
Custom instructions set rules for every chat, memory keeps facts about you, and Projects bundle chats, files, and instructions for one body of work.
