--- title: "Remote MCP auth patterns compared | Agent MCP Directory" description: "Remote MCP auth patterns compared. Pick between an open server, an API key and OAuth with or without client registration." canonical: https://agentmcpdirectory.com/guides/remote-mcp-auth-patterns site: "Agent MCP Directory" last_updated: 2026-11-05 section: "Guides" --- # Remote MCP auth patterns compared | Agent MCP Directory > Remote MCP auth patterns compared. Pick between an open server, an API key and OAuth with or without client registration. Source: https://agentmcpdirectory.com/guides/remote-mcp-auth-patterns Site: Agent MCP Directory Last reviewed: 2026-11-05 # Remote MCP auth patterns compared Pick between an open server, an API key and OAuth with or without client registration, and see what each looks like to an agent and in this directory. Of 817 reachable endpoints, 263 need no credentials and 533 publish OAuth metadata. ## Steps 1. Decide who the server is for: a public docs server can stay open, a product server acts for a signed-in user. 2. Open: list tools to any client and keep anything sensitive out of reach. 3. API key: answer 401 with a message a person can act on; an agent cannot register itself for a key. 4. OAuth: publish protected resource metadata so a client finds the flow without a person wiring it. 5. Test the 401 challenge, the metadata documents and PKCE with S256 before launch. ## What the sources say - Ora's catalog grades auth by fit: docs MCP servers should be public and product MCP servers should require OAuth. ([ora.ai](https://ora.ai/api/checks?utm_source=agentmcpdirectory.com&utm_medium=referral&utm_campaign=guide), read 5 November 2026) - Ora checks OAuth metadata under RFC 8414 as a way for agents to discover the sign-in flow automatically. ([ora.ai](https://ora.ai/api/checks?utm_source=agentmcpdirectory.com&utm_medium=referral&utm_campaign=guide), read 5 November 2026) - Ora checks that the OAuth flow supports PKCE with the S256 method. ([ora.ai](https://ora.ai/api/checks?utm_source=agentmcpdirectory.com&utm_medium=referral&utm_campaign=guide), read 5 November 2026) - The 2026-07-28 MCP specification requires servers to implement OAuth 2.0 Protected Resource Metadata (RFC 9728). ([modelcontextprotocol.io](https://modelcontextprotocol.io/specification/2026-07-28/basic/authorization), read 4 November 2026) - Clients obtain a client ID through Client ID Metadata Documents, pre-registration or Dynamic Client Registration; the specification marks CIMD as SHOULD and DCR as MAY and deprecated. ([modelcontextprotocol.io](https://modelcontextprotocol.io/specification/2026-07-28/basic/authorization), read 4 November 2026) - Ora says that when an MCP server requires authentication, a scan returns MCP\_AUTH\_REQUIRED with no score or grade. ([ora.ai](https://ora.ai/llms.txt?utm_source=agentmcpdirectory.com&utm_medium=referral&utm_campaign=guide), read 5 November 2026) ## The four patterns in the directory Reachable endpoints by the auth type the connector saw on 4 November 2026. The table has the same counts, what a client sees and four of the most visited examples. | Pattern | Endpoints | Tools listed | What a client sees | Examples | | --- | --- | --- | --- | --- | | No authentication | 263 | 263 | The server listed its tools to a client that sent no credentials. | Google, Cloudflare, Google Cloud, Microsoft | | API key | 19 | 0 | The server answered 401 or 403 and asks for a key or bearer token with no OAuth metadata for an agent to follow. | StackOverflow, Appcircle, Bitculator, Cavyro | | OAuth with client registration | 517 | 0 | The server publishes OAuth metadata and a registration endpoint, so a client can register itself without a human filling in a form first. | Sentry, PayPal, Stripe, Amplitude | | OAuth without client registration | 16 | 0 | The server publishes OAuth metadata but no registration endpoint, so a client must be registered by hand or identified by a client ID metadata document. | GitHub, Microsoft 365, Zoom, HubSpot | ## What a scanner expects Ora's catalog grades the match between a server's auth and its job: docs servers should be public and product servers should require OAuth, and its check asks whether the auth matches what the server does. A server that requires sign-in cannot be scored from outside at all; Ora returns `MCP_AUTH_REQUIRED` with no score or grade. [How Ora tests an MCP server](https://agentmcpdirectory.com/test-your-mcp-server/) and [the OAuth checks](https://agentmcpdirectory.com/mcp-checks/#servers). The OAuth route itself, with client ID metadata documents and dynamic registration, is in [the OAuth guide](https://agentmcpdirectory.com/guides/oauth-for-mcp-cimd-dcr/). ## Testing your own MCP server Ora scans an MCP server URL and runs 28 of its 132 public checks on it, with check sets that differ for a docs server and a product server. It is the check this directory recommends; it reads public URLs only and publishes no repeat-scan data. [The reasons, the limits and the alternatives](https://agentmcpdirectory.com/test-your-mcp-server/). Edition 4 November 2026 Method [How rows are verified](https://agentmcpdirectory.com/method/) Data [CSV and JSON](https://agentmcpdirectory.com/data/) Markdown [This page as markdown](https://agentmcpdirectory.com/guides/remote-mcp-auth-patterns/index.md) ## Sources - [Remote MCP auth patterns compared](https://modelcontextprotocol.io/specification/2026-07-28/basic/authorization), read 4 November 2026 - [ora.ai/api/checks](https://ora.ai/api/checks?utm_source=agentmcpdirectory.com&utm_medium=referral&utm_campaign=guide), read 5 November 2026 - [ora.ai/llms.txt](https://ora.ai/llms.txt?utm_source=agentmcpdirectory.com&utm_medium=referral&utm_campaign=guide), read 5 November 2026 Last reviewed 5 November 2026