For most of 2025, agent discovery meant one question — where do I find MCP servers? — and the ecosystem gave it a clean answer: a single, community-run official MCP registry. Neutral, singular, protocol-owned. The whole point was that there'd be one place to look, so nobody had to.
In the second quarter of 2026 the question moved up a level, from tools to the things that call tools. Where do I find agents? And this time the answer arrived three times — from AWS, Google, and Microsoft — in the same few weeks, from three companies that do not share a catalog. That's the story worth understanding, because the two kinds of registry look similar and do very different jobs.
What an agent registry actually is#
An MCP registry indexes exactly one resource type: MCP servers. You look up a server by name, read its package metadata, and connect — the model we walked through in the official MCP registry explained. That's the whole surface, and its minimalism is a feature.
An agent registry is a superset. Take AWS's Agent Registry, shipped in preview inside Bedrock AgentCore in April. It catalogs five record types — agents, tools, MCP servers, agent skills, and custom resources — as structured, governed entries. You find them with hybrid search: describe a use case in natural language ("payment processing") and semantic matching surfaces records tagged "billing" or "invoicing" that a keyword search would miss.
The bigger difference is governance, which MCP registries barely have. Every record moves through an approval workflow — draft → pending approval → discoverable — so nothing is callable until an admin signs off. Records carry versions, can be deprecated, and every access and admin action lands in CloudTrail. And in a neat recursion, the registry exposes itself as an MCP server: a coding agent in your IDE can query and invoke registered agents through the same protocol it uses for everything else.
An MCP registry answers "where are the tools?" An agent registry answers "which agents exist, are they approved, and who is allowed to call them?"
That governance framing is why this is an enterprise product, not a directory. The problem it names is agent sprawl — hundreds of half-forgotten agents nobody can inventory. The registry is the catalog plus the gate.
The part nobody's solving#
Here's the turn. The MCP registry defeated fragmentation by being one registry. The agent registry reintroduces fragmentation by being a cloud-vendor registry — and there are already at least three.
Google shipped an Agent Registry wired into Vertex AI Agent Builder and Apigee, centered on MCP and tool governance. Microsoft's Entra Agent ID adds a central directory of organizational agents, leaning on identity — Conditional Access, Identity Protection signals, prompt-injection detection at the auth layer. AWS pitches its own as cloud-agnostic. The scopes overlap, the centers of gravity differ, and — the load-bearing fact — none of them interoperate.
Play that forward for a real company. It runs agents on AWS, uses Copilot across Microsoft 365, and deploys custom agents on Google Cloud. That's three registries, three approval workflows, three audit trails, three answers to "which agents do we have." The sprawl the registries promised to eliminate doesn't disappear; it relocates one level up, from unmanaged agents to unmanaged registries of agents. Forbes called agent registries the new battleground for the cloud giants, which is exactly right and exactly the problem — a battleground is not an interoperable standard.
The tell is in the lineage. The MCP registry came from the protocol community and was designed to be singular because singular is the only shape that makes discovery free. The agent registries came from the platforms, and each is designed to be the center. If you're choosing one this year, choose on where your agents actually run and how badly you need the governance today — but choose knowing the neutral, cross-vendor agent registry that would make this a solved problem doesn't exist yet, and no vendor shipping one has an incentive to build it.
