Spellcast was built with GPT-6 Astra.
I used Astra heavily to design and ship the desktop stage: passive bubbles for side thoughts, an editable Canvas for results, and completion notices when a turn ends. That burned through my Astra Pro 20x before launch day.
Runtime target today: Codex on Windows (MCP + hooks). Local-first, open source, EN/中文 UI. The clip shows one host path; the core idea is the desktop stage around the agent.
