Use when work should be led as a multi-model orchestration — delegating to model-pinned subagents and a cross-vendor peer instead of doing everything in the main context. Trigger whenever the user asks to orchestrate, delegate, fan out, act as tech lead, use worker/sub agents on a task, split design work from grunt work, get a second opinion from Codex or another vendor, run two models on the same question and reconcile them, or conserve expensive-model/context usage — and for any large multi-part refactor or migration where the user says not to read/burn everything in the main context.
Run a multi-model orchestration workflow with Fable 5 as the lead. Delegate reasoning-heavy work (architecture, debugging, algorithm design) to a deep-reasoner subagent (Opus), mechanical work (boilerplate, tests, formatting, bulk edits) to a fast-worker subagent (Sonnet), and fresh-perspective or high-stakes problems to Codex, a different-vendor GPT-5 peer. Use to orchestrate, delegate, fan out, get a second opinion from Codex, run Opus and Codex in parallel and synthesize, or act as tech lead.