Manifest and package

Package layout

A package is a zip file with the extension .mcplugin. mumcord-plugin build creates it.

File	Required	Notes
manifest.json	yes	At most 16 KiB. See below.
plugin.wasm	yes	A WebAssembly component for the world mumcord:plugin@1.0.0.
i18n/en.json	yes	English texts. Other languages are i18n/<tag>.json (BCP 47, for example de). At most 64 KiB each.

Translations. Third-party plugins only need i18n/en.json. Official plugins (published from the Mumcord plugins repository) must ship i18n/<tag>.json for all 24 Mumcord languages (bg cs da de el en es et fi fr ga hr hu it lt lv mt nl pl pt ro sk sl sv), each with exactly the keys of en.json. Plural keys may use different _zero/_one/_two/_few/_many variants per language, but _other is required everywhere. CI fails and lists missing languages and keys. | assets/** | no | Images for ui::image, the plugin icon. At most 512 KiB each. SVGs are sanitised on install. | | README.md, LICENSE | official plugins | Recommended for every plugin. |

Limits: the package is at most 5 MiB, unpacks to at most 8 MiB and holds at most 200 files. Official plugins may be larger because they can bundle a web app: at most 64 MiB packed, 96 MiB unpacked and 10,000 files, with each file under web/ at most 16 MiB. Files under web/ may be .html, .css, .js, .json, .wasm, .woff2, .png, .webp or .svg. Because SVGs are sanitised on install, the installed bytes can differ from the package bytes.

manifest.json

{
  "manifest": 1,
  "id": "my-plugin",
  "name": "My plugin",
  "description": "Wave at the channel.",
  "version": "0.1.0",
  "api": "^1.0",
  "authors": ["Your name"],
  "license": "Apache-2.0",
  "categories": ["fun"],
  "permissions": {
    "required": ["ui.panel"],
    "optional": [{ "id": "peers.messages", "suggested": true }]
  }
}

Field	Required	Meaning
manifest	yes	Format number. Currently 1.
id	yes	Unique, permanent id. Must match the registry folder name.
name, description	yes	Fallback texts. Translated by manifest.name and manifest.description in i18n/*.json (name at most 32 characters, description at most 140).
version	yes	Semantic version. A new release needs a higher version.
api	yes	Plugin API version range, for example ^1.0. The current API is 1.0.0.
mumcord	no	Version range of Mumcord the plugin needs.
authors	yes	List of names.
license	yes	SPDX identifier of an OSI-approved licence.
categories	yes	One or more of fun, games, chat, voice, accessibility, looks, tools.
permissions.required	yes	Permissions the user must accept to install.
permissions.optional	no	Permissions the user can switch off. suggested: true starts them switched on in the install prompt. The plugin must work without them.
commands	no	Slash commands: { "name", "description", "usage" }. Needs the commands permission.
triggers	no	Chat trigger words such as ["!poll"]. A channel message that starts with one arrives as a ChatTrigger event. Needs chat.triggers.
chat_patterns	no	At most 2 entries { "pattern", "description" }. A pattern is at most 256 characters and must start with ^ or \A. A channel message whose plain text matches arrives as a ChatMatch event. Needs chat.patterns. Translate the description with the key chat_patterns.<n>.description.
messaging.max_payload	no	Largest peer message the plugin sends, at most 997 bytes (default 997).
messaging.default_visibility	no	everyone, friends or nobody: preselected in the install prompt.
memory_mib	no	Memory limit, at most 32 MiB.
storage_quota_kib	no	Storage quota, default 256 KiB, at most 1024 KiB.
net	no	Only for official plugins with net.http.
icon	no	Path of an image in assets/.

Unknown fields and unknown permission ids are errors. Ids that start with mumcord- or core- are reserved.

Translations

Every user-visible string of the manifest is looked up in the active language and falls back to English. Keep keys stable between versions. Strings you draw with ui::text are yours to translate: Mumcord sends the current language (a BCP 47 tag such as de) as the language-changed event right after start and whenever it changes.