Psychograph
SpecificationMCP DNS Discovery · Draft v0

Draft convention · v0 · 2026-07-08

MCP DNS Discovery

A minimal DNS TXT convention for advertising a domain’s MCP endpoint, in the lineage of SPF/DKIM/DMARC-style service discovery. Authored and used in production by Psychograph MCP. Status: draft — versioned so records survive evolution; if the MCP ecosystem standardizes a different mechanism, this convention will track it and the version tag allows orderly migration.

The record

_mcp.<domain>.   TXT   "v=mcp1; endpoint=https://mcp.<domain>; manifest=/.well-known/mcp-manifest"

Fields

  • v — convention version. Current: mcp1.
  • endpoint — absolute HTTPS base URL of the MCP endpoint (Streamable HTTP).
  • manifest — path (relative to endpoint) of a JSON manifest describing tools, transport, and auth.

Resolution flow

  1. Agent holds a domain, e.g. client.com.
  2. Agent resolves TXT _mcp.client.com → endpoint + manifest path.
  3. Agent fetches the manifest, then speaks MCP to the endpoint.
  4. Fallback (record absent): probe https://mcp.<domain>/.well-known/mcp-manifest — the mcp. subdomain convention is the degraded path.

Live examples

  • curl https://mcp.psychogra.ph/.well-known/mcp.json
  • curl https://mcp.psychogra.ph/mcp/demo — demo business endpoint (POST JSON-RPC)

Feedback: [email protected]. Implementations welcome — this page is the canonical reference for v=mcp1.