According to Satya Nadella on X, Microsoft has added Grok 4.1 Fast to Copilot Studio’s multi‑model lineup to give builders more choice and flexibility for custom agents. According to Microsoft’s Copilot Studio product positioning, the platform already supports multi‑model orchestration for enterprise copilots, and adding Grok 4.1 Fast expands options for latency‑sensitive workflows such as conversational routing, rapid retrieval‑augmented generation, and agent tool use. As reported by Nadella’s post, this move strengthens Copilot Studio’s model marketplace approach, enabling organizations to match tasks to model strengths and optimize for speed, cost, and compliance in regulated deployments. According to Microsoft product documentation, multi‑model support can reduce vendor lock‑in and improve resilience by allowing fallback or model switching, creating opportunities for ISVs to package vertical copilots, for enterprises to A/B test prompts across models, and for developers to tune model selection by use case and region.