MUSH Compatibility

UrsaMU is not a drop-in replacement for PennMUSH, TinyMUSH, or MUX2. It is a fresh platform with a different architecture — WebSocket-native, TypeScript, sandboxed scripts instead of MUSHcode.

If you are migrating from a traditional MUSH or hosting your first server, this page tells you exactly what works today and what is planned.

Updated for v2.6.0.

What Works Today

MUX Softcode Support

UrsaMU ships a TinyMUX 2.x compatible softcode evaluator
alongside the TypeScript sandbox. Builders: start with
the Softcode Guide (how-to, examples,
$/^, UDFs). This section is the parity inventory.

How it works

• TypeScript/JS attributes (default) — Deno Web Worker
  sandbox. See Attribute Scripts.
• Softcode attributes — dedicated softcode worker, 100ms
  wall-clock timeout.

&GREET/softcode me=[name(%#)] greets you!

The /softcode flag persists and routes eval through the
softcode engine. Omitting it uses TypeScript unless the
value is auto-detected as MUX softcode.

Supported functions (~250 total)

Substitutions

All standard TinyMUX substitutions are supported: %# (enactor dbref), %! (executor dbref), %@ (caller), %N/%n (name), %L (location), %s/%S/%o/%O/%p/%P/%a (pronouns), %0–%9 (args), %q0–%qz (registers), ## / #@ (iter variables), %VA–%VZ (object attributes), %r (newline), %t (tab), %b (space), %% (literal %), full ANSI color codes (%ch, %cr, %cg, %cb, %cy, %cw, %cc, %cn, %xN truecolor).

TinyMUX compatibility stubs

@tag / @ltag — Named Object Registry

UrsaMU ships a RhostMUSH-style named object registry. Instead of remembering dbrefs, you can assign human-readable names to objects.

@tag (global, wizard-only)

@tag citygate=here          Register current room as "citygate"
@tag vault=#142             Register #142 as "vault"
@tag                        (no args) list all tags
@tag/remove citygate        Remove the "citygate" global tag

Global tags are visible to everyone. Only wizards and admins may create or remove them. When a tagged object is destroyed, its tags are automatically removed.

@ltag (personal, any player)

@ltag home=here             Register current room as your "home"
@ltag/list                  List all your personal tags
@ltag/remove home           Remove your personal "home" tag

Personal tags are scoped to your character (max 50). They are visible only in your own softcode evaluations.

Softcode usage

[tag(citygate)]             → dbref of the citygate room
[istag(vault)]              → 1 if "vault" global tag exists
[tagmatch(here,citygate)]   → 1 if here is tagged "citygate"
[ltag(home)]                → dbref of your personal "home" tag
[name(#citygate)]           → name of the citygate object (shorthand)

The #tagname shorthand works anywhere an object reference is accepted in softcode (personal tags shadow global ones).

What’s Different from Traditional MUSH

Format-Attribute Pipeline

Eight engine-known format slots route through both softcode attributes on the
object and plugin-registered handlers (priority: softcode attr → plugin handler
→ fallback):

NAMEFORMAT, DESCFORMAT, CONFORMAT, EXITFORMAT, WHOFORMAT,
WHOROWFORMAT, PSFORMAT, PSROWFORMAT.

Plugins may also register arbitrary uppercase slot names (e.g. MAILFORMAT,
BBROWFORMAT) — FormatSlot is an open union as of v2.3.4.

// TS handler
registerFormatHandler("WHOROWFORMAT", (ctx) => `${ctx.name} - idle ${ctx.idle}`);

// Softcode template (v2.4.0)
registerFormatTemplate("WHOFORMAT", "[center(===,78,=)]%r[u(#1/HEADER)]");

Lock Expressions (v2.2.0+)

Locks support &&, ||, ! with () grouping plus the legacy &/|
operators. Built-in lockfuncs: flag(name), attr(name[, val]), type(name),
is(#id), holds(#id), perm(level). Custom lockfuncs register via
registerLockFunc(name, fn).

lock: "connected && (flag(wizard) || attr(tribe, glasswalker))"

Planned Enhancements

Connecting with a Traditional MU* Client

UrsaMU’s Telnet sidecar makes it compatible with any standard MU* client:

WebSocket-capable clients can connect directly to port 4202 (or 4203 for HTTP/WS).