Player-session MUD protocol

MCP

MUD Client Protocol v1 and v2.1

Niche use Documented current use Legacy

A package-negotiation framework associated mainly with MOO and MUCK clients, including editor and application packages.

Protocol overview

First seen
1990s
Present-day status
Niche use
In use today?
Yes, with documented current use.
Legacy?
Yes. It may still matter for compatibility or historical systems.
Layer
Player-session MUD protocol
Transport
In-band 7-bit ASCII lines beginning with #$#
Research validated

Current use and fit

Still relevant inside its MOO/MUCK niche, but not a general replacement for GMCP.

Implementation essentials

  • Exchange MCP version ranges, a session key, and package capabilities.
  • Implement line quoting and package framing exactly.
  • Keep MCP packages behind application adapters.

Compatibility and safety notes

  • The session key prevents accidental framing collisions; it is not cryptographic authentication.
  • Outside the MU* ecosystem, current support is limited.

Original specifications and sources

Where an original site has disappeared, a preservation archive is linked and identified as such. MUDVerse does not claim authorship of the original protocol.