Seems this protocal is not in version 2. I also noticed an implimentation of it was never developed (got side tracked with some issue about what sort of 'window' should be used to edit things), even as a plugin. The specs for 2.1 are here:
http://www.belfry.com/fuzzball/trebuchet/mcp.html
The client 'trebuchet' seems to support a lot of what Mushclient does *and* MCP, which isn't a good thing if they have a choice between a superior client that "won't" support a protocol the server uses or a slightly less impressive one that does. Might be a good idea to take a second look at this.
I looked at MCP a while back, and wasn't all that impressed. It talks about "In-band lines", "Out-of-band lines", "Messages", "authentication keys" and so on. It seemed to me to be very complicated. What problem are they trying to solve exactly?
I found a while back that implementing MXP was a lot of work, and still many MUDs don't use it. I imagine the same thing applies to MCP.
Any text MUD that wants to maximize its chances with players will not use something (like MCP) that is only supported by a small number of clients.
The problem here is that MCP 'is' being used by muds. A lot of them us it to talk directly to things like special editors and the like. MXP is in many respects a bit more of a toy, which no one wants to play with. Frankly, it appears it 'may' be possible to impliment the basics in a plugin, just figured it might be a good idea to keep track of the trends going on. And the impression I got was that, at least in some circles, this is starting to become something common. This may especially be the case in mucks or the like, which allow the player to edit content or even for staff on some muds, again, because of the ability to call up an editor.
zMud for example recently added these MCP packages:
mcp (without the optional cords) - Basic MCP module
mcp-negotiate - MCP negotiation module
dns-org-mud-moo-simpleedit - Editor.
dns-com-awns-displayurl - Opens a browser to display a URL.
dns-com-awns-ping - Like the normal Ping command.
dns-com-vmoo-client - Client version & screen size.
and two related to MXP and MSP.
Some others that exist are listed here:
http://www.awns.com/tkMOO-light/plugins/
Though, one *huge* problem seems to be the lack of a true ActiveX version of TCL... The version you tried to add support for seems to be little more than a wrapper, which hasn't been worked on since 2000. All of the functions tend to be TCL files. Its becoming the standard 'plugin' system for a lot of clients.
In any case, it could prove to be a problem some point down the road for Mushclient to remain a valid competitor. Unfortunately since it relies a lot of TCL, solving the problem isn't likely to be easy... :(