Spotify open-sources 'shunt' Claude Code plugins cutting token usage ~90% via cheap worker delegation

Spotify's Sep 3 engineering post describes Portal AiKA Modes — declarative agents on ephemeral runtimes — with a Claude Code plugin 'shunt' (github.com/spotify/portal-ai-plugins) whose PreToolUse hooks route bulk file reads and boilerplate generation to a cheap worker (e.g. Gemini 2.5 Flash), returning only summaries to Claude. Measured ~90% mean token savings on bulk reads across four Java-monorepo scenarios, at the cost of 10-30s delegation latency and no support for edits or deep reasoning.