Agents Quietly Cross the Vendor Line

Hermes can now run on your X Premium and Grok subscriptions, Microsoft Copilot Studio added MCP, and Singapore is building a national agent gateway. The single-vendor agent stack is quietly ending.

This week made the case that agents are no longer single-vendor products — they're orchestration layers borrowing capability from wherever the user already pays. xAI letting Grok subscribers run from inside Nous Research's Hermes Agent, Microsoft Copilot Studio adding native MCP support, and Singapore's government building a national MCP gateway all point the same direction: the integration plane, not the model, is the contested surface.

The xAI moves are the clearest signal. In a post on May 15, xAI confirmed paying Grok subscribers can now access their model from inside a competitor's agent — Hermes, built by Nous Research. The next day, xAI extended the partnership so Hermes can pull from X Premium content and search live X posts. A year ago, vendors guarded their subscription tiers as walled gardens. Treating them as bring-your-own credentials inside a third-party agent is a different posture entirely.

Microsoft and Mistral pull on the same thread from different ends. Microsoft Copilot Studio now ships native MCP support so any MCP server can register as a tool — meaning Copilot agents can call out to anything that speaks the protocol. Mistral's Medium 3.5 release on April 29, 2026 targets agentic and coding workflows explicitly, paired with a remote coding agent in their Vibe IDE. Even Codex has changed enough in 3 months that swyx described seeing agentic Excel on Mac as the new bar for what counts as a real agent.

For builders, the implication is that the lock-in question is moving up a layer. Your stickiness is no longer "which model do they use" — it's "which agent runtime owns the user's tool registry." For buyers procuring agents, the right diligence question is now what protocols the system speaks, not which model is under the hood. Singapore's national MCP gateway, sized for an estimated 1.3 billion agents inside 2 years, suggests at least one government already views this as critical infrastructure rather than vendor convenience.

The bottom line: Pick agent platforms by their interop surface, not their underlying model — the model will swap 3 times before next year, but protocol commitments compound.

Sources