MCP Server Registry Discovery: connect Codex to an enterprise MCP server catalog with a single command

We maintain an open-source MCP Gateway Registry that solves exactly what's being discussed in #22930 (tool discoverability) and #8925 (plugin marketplaces) from the enterprise angle. It's a centralized catalog of MCP servers, agents, and skills with OAuth/DCR-based access control, and it already works with Codex CLI today via Streamable HTTP transport. We'd like to propose a tighter integration path.

The problem:
Codex's MCP support is excellent for connecting to individual servers, but there is no built-in way to discover which servers are available across an organization. Today, teams share server URLs through wikis, Slack, or README files, and each developer manually runs codex mcp add for every server they need.

How it works today (zero changes needed on Codex side):

The MCP Gateway Registry already exposes itself as an MCP server. A Codex user can add it with one command:

codex mcp add ai-registry --transport streamable-http --url https://your-enterprise-registry/mcp

Once connected, the AI assistant gains a search_registry tool that lets it find and connect to any server in the catalog on the user's behalf. The registry supports:

• Semantic search across all registered MCP servers, agents, and skills
• OAuth/DCR integration with Keycloak and Microsoft Entra ID (so each developer authenticates individually, no shared tokens)
• Per-user authorization with scope-based access control
• CIMD support (Client ID Metadata Document, draft-parecki-oauth-client-id-metadata-document) for zero-touch client registration

What deeper integration could look like:

1. Registry-aware codex mcp add: A --registry <url> flag that searches a registry and presents matching servers for the user to pick from, instead of requiring the full endpoint URL upfront. The registry already implements a /.well-known/registry-card discovery endpoint that describes the registry instance and its capabilities.

1. Plugin marketplace source: Allow enterprises to point Codex at their registry as a private marketplace source, so servers appear in /plugins alongside the curated directory.

1. Auto-discovery via well-known URL: The registry already publishes a /.well-known/mcp-servers endpoint that returns JSON with all discoverable MCP servers. If Codex supported fetching this well-known URL from a configured registry, it could auto-populate available servers without the user needing to search manually.

Enterprise value:

• Developers on Codex get access to dozens of organization-approved MCP servers without manual configuration
• Security teams maintain centralized governance (who can access which servers, with audit trails)
• Onboarding goes from "here's a wiki page with 15 URLs" to "connect to the registry, search for what you need"

Demo:
A 4-minute walkthrough of Codex CLI connecting to the registry and discovering servers via DCR:
https://app.vidcast.io/share/25ed9141-b890-423c-b063-96da5cd9d533

!AI Gateway Registry Landing Page

Additional information

• MCP Gateway Registry repo: https://github.com/agentic-community/mcp-gateway-registry
• DCR/OAuth integration already tested end-to-end with Codex CLI (see Integration Guide)
• Related Codex issues: #22930 (tool discoverability), #8925 (plugin marketplaces), #20621 (private marketplace sources)
• The registry is open-source (Apache-2.0), self-hostable, and deploys on AWS ECS, EKS (Helm), or Docker Compose

This is not a PR submission. Happy to discuss the integration approach and provide technical details for the team to evaluate.