Everyone built a tool directory
Between November 2024 and mid-2026, four organizations that don't coordinate with each other shipped the same object: a registry of callable capabilities with credentials attached and a log underneath. Anthropic's MCP registry. OpenAI's Connector Registry. Kong's enterprise MCP gateways. The Linux Foundation's A2A agent cards. Different vendors, different politics, one shape. When independent teams under different incentives converge on one structure, the structure is probably load-bearing. This page plots the convergence.
The timeline, compressed
MCP was open-sourced in November 2024. Spec v2 and OpenAI's adoption landed March 2025. The official MCP Registry launched in preview September 2025 — "a community driven registry service for Model Context Protocol servers," an app store for tool servers, with namespace verification and an API freeze so clients could integrate against it. Anthropic donated the whole protocol to the Linux Foundation in December 2025. By March 2026 the registry held nearly 2,000 server entries and the SDKs were pulling roughly 97 million downloads a month.
Nineteen months from side project to Linux Foundation standard. For an infrastructure protocol that is close to record pace — and the registry, not the wire format, is the part everyone copied.
OpenAI built the same thing wearing a suit
AgentKit's Connector Registry, launched October 6, 2025, is "a unified administrative panel" that "consolidates data source access across ChatGPT and the OpenAI API" — prebuilt connectors, MCP support for third-party tools, centralized credential management, role-based access, audit logging.
Strip the enterprise wording and read the parts list: a table of callable things, credentials held centrally, calls logged. When OpenAI later announced Agent Builder's shutdown for November 30, 2026, the Connector Registry was explicitly kept. The canvas was disposable. The registry wasn't.
The agent-to-agent layer converged on the same answer
A2A — Google's protocol, transferred to the Linux Foundation in June 2025 — crossed "more than 150 organizations supporting the standard" by April 2026, with production deployments on Google Cloud, Azure AI Foundry, and Amazon Bedrock. Its discovery mechanism is the agent card: a published, structured description of what an agent can do and how to reach it.
An agent card is a directory row. Discovery-by-registry won at the agent layer too, which means the same object now sits at both layers of the stack: tools below, agents above.
Where this build sits on the plot
The miscsubjects kernel has run this shape since before the registry layer had a name: 887 directory rows behind one dispatch ingress, each row carrying its own documentation, auth tier, and examples; every invocation written to a ledger; external MCP servers absorbed as rows and the whole directory re-exported as an MCP server. When the ecosystem grew a registry protocol, plugging in took one import tool and one export route, because the internal shape already matched.
That is the comparative point, stated carefully: not "this build invented the pattern" — Unix had a syscall table, Stripe had an API index, the pattern is old. The point is that the 2024–26 agent ecosystem rediscovered it under competitive pressure, four times, in public.
What the convergence predicts
Two components appear in every independent version: the registry and the log. Two components appear in none of the mainstream versions yet: enforcement of what a caller may do (beyond OAuth scopes), and a tamper-evident record chain rather than an operational trace. Kong's 2026 enterprise registries are adding approval workflows and security scanning — governance bolted onto discovery. The next convergence, if the pattern holds, is authority that travels with the call: scoped, expiring, attenuating tokens instead of long-lived API keys. That layer is where this build already lives, and where the ecosystem's papers — not yet its products — are pointed. The follow-up page walks that gap.
Key evidence
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