# Discovery of Model Context Protocol Servers via DNS TXT Records vs MCP Server Cards (SEP-2127)

They sit at the same step and overlap in purpose; the fields above are the basis for choosing.

[1 Discover](/category/discover/) [Discovery of Model Context Protocol Servers via DNS TXT Records](/protocols/mcp-dns-discovery/) · [1 Discover](/category/discover/) [MCP Server Cards (SEP-2127)](/protocols/mcp-server-cards/)

|  | [Discovery of Model Context Protocol Servers via DNS TXT Records](/protocols/mcp-dns-discovery/) | [MCP Server Cards (SEP-2127)](/protocols/mcp-server-cards/) Server Card |
| --- | --- | --- |
| Lifecycle step | 1 Discover: What is here, and where? | 1 Discover: What is here, and where? |
| Answers | How can a client discover an MCP server's endpoint, the operating organisation's identity, and a signed ~handle identity envelope using DNS TXT records under a domain? | How can a client learn what an MCP server offers before connecting to it? |
| Governed by | Individual Internet-Draft by a single author; not adopted by an IETF working group per the page text (Network Working Group, Intended Status: Informational). | Model Context Protocol project (SEP process, MCP governance) |
| Status (issuer's words) | Active Internet-Draft (-09, Informational; expires 2027-04-25) | SEP-2127 Final (2026-10-06), Extensions Track charter; the MCP Registry working group page still describes Server Cards as experimental |
| Version | draft-morrison-mcp-dns-discovery-09 (2026-10-22) | SEP-2127 (Final) (2026-10-06) |
| Form / transport | DNS record | document format |
| Found at | _mcp.<domain> | GET <streamable-http-url>/server-card |
| Implementation | none found | multi-implementation |
| Evidence | 1 reported, 1 verified | 7 verified, 1 reported |
| Primary use case | Let agents discover my API or service | Let agents discover my API or service |
| Last verified | 2026-10-23 (current) | 2026-10-23 (current) |
| Specification | [https://datatracker.ietf.org/doc/html/draft-morrison-mcp-dns-discovery-09](https://datatracker.ietf.org/doc/html/draft-morrison-mcp-dns-discovery-09) | [https://github.com/modelcontextprotocol/modelcontextprotocol/blob/main/seps/2127-mcp-server-cards.md](https://github.com/modelcontextprotocol/modelcontextprotocol/blob/main/seps/2127-mcp-server-cards.md) |

## When to use which

- Choose Discovery of Model Context Protocol Servers via DNS TXT Records when your question is “How can a client discover an MCP server's endpoint, the operating organisation's identity, and a signed ~handle identity envelope using DNS TXT records under a domain?” and you accept its maturity: status "Active Internet-Draft (-09, Informational; expires 2027-04-25)", implementation none found.
- Choose MCP Server Cards (SEP-2127) when your question is “How can a client learn what an MCP server offers before connecting to it?” and you accept its maturity: status "SEP-2127 Final (2026-10-06), Extensions Track charter; the MCP Registry working group page still describes Server Cards as experimental", implementation multi-implementation.

Guidance is derived from the two records (question, status, implementation, prerequisites, pairings), not from opinion. Each record's page carries its numbered references.

## Read the full articles

- [Discovery of Model Context Protocol Servers via DNS TXT Records](/protocols/mcp-dns-discovery/): How can a client discover an MCP server's endpoint, the operating organisation's identity, and a signed ~handle identity envelope using DNS TXT records under a domain?
- [MCP Server Cards (SEP-2127)](/protocols/mcp-server-cards/): How can a client learn what an MCP server offers before connecting to it?

Ask the MCP server to compare any two: the compare-protocols prompt, or get on both ids. [Connect](/connect/).

[mcp-dns-discovery.json](/data/protocols/mcp-dns-discovery.json) · [mcp-server-cards.json](/data/protocols/mcp-server-cards.json) · [Markdown](/compare/mcp-dns-discovery-vs-mcp-server-cards/index.md)