website/content/docs/ircv3.md

IRCv3 capabilities

Clients negotiate capabilities with CAP LS / CAP REQ. echoIRCd advertises the following. draft/multiline, sasl, and draft/account-registration carry =-value parameters (limits, the SASL mechanism list, enabled sub-features) to CAP-302 clients.

Ratified

Capability	Meaning
sasl	SASL authentication (mechanism list attached for CAP 302)
server-time	A time= tag with each message's server timestamp
message-tags	Generic message-tag support, including relaying client + tags
multi-prefix	Show all of a member's status prefixes in NAMES/WHO
away-notify	Real-time AWAY / back notifications
account-notify	Notify when a user logs in/out of an account
extended-join	JOIN carries the account name and realname
chghost	Real-time host/ident change notifications
userhost-in-names	Full nick!user@host in NAMES
echo-message	Echo the sender's own PRIVMSG/NOTICE back
invite-notify	Notify channel ops when a user is invited
setname	Real-time realname change notifications
extended-monitor	MONITOR reflects extended state changes
account-tag	An account= tag identifying the sender's account
standard-replies	Structured FAIL / WARN / NOTE replies
labeled-response	Correlate a command with its response via label
batch	Group related messages into a BATCH
cap-notify	Tell the client when caps are added/removed

Draft & vendor

Capability	Meaning
draft/chathistory	Request replay of past channel/DM messages
draft/event-playback	Include channel events (JOIN/PART/QUIT/NICK/MODE/TOPIC/KICK) in history
draft/message-redaction	REDACT a previously-sent message
draft/pre-away	Set AWAY during registration
draft/metadata-2	Per-user/channel arbitrary metadata
draft/multiline	Send one logical message across multiple lines
draft/account-registration	In-band account REGISTER / VERIFY
draft/json-log	Structured JSON tag on server notices (opers)
draft/extended-isupport	Re-request ISUPPORT (005) tokens on demand
draft/relaymsg	Send channel messages under a spoofed relay nick (bridges)
draft/channel-rename	Rename a channel in place (RENAME)
draft/read-marker	Per-conversation read-marker sync across devices
draft/webpush	Web Push subscription for backgrounded/away notifications
draft/filehost	Advertise an external file-host + signed upload links
no-implicit-names	Suppress the automatic NAMES burst on JOIN

Notable capabilities

A few of these do more than the one-line table can show.

Channel rename

The draft/channel-rename capability lets a channel operator rename a channel in place, keeping its membership, modes, topic, bans and timestamp:

RENAME <#old> <#new> [<reason>]

Members whose client negotiated the capability get a single RENAME message and stay in the channel seamlessly. Members without it are moved with an automatic PART + JOIN (topic and names preserved), so their client follows the channel too. A change that only alters the case of the name needs no move at all.

The server enforces a few rules:

• you must be a channel operator (or an IRC operator);
• the channel prefix can't change (#foo → &foo is refused);
• the new name must be valid and not already in use, and can't be CBAN'd (operators bypass that);
• a registered (+r) channel is owned by services — a client can't rename it; ask ChanServ (/msg ChanServ RENAME <#channel> <#newname>), which does it over the server link. Operators may rename registered channels directly.

Failures come back as standard replies, e.g. FAIL RENAME CANNOT_RENAME … or FAIL RENAME CHANNEL_NAME_IN_USE ….

Message history

draft/chathistory replays a channel's or DM's recent messages from the server's per-conversation store (the CHATHISTORY command). With draft/event-playback the replay also carries JOIN/PART/QUIT/NICK/MODE/TOPIC/KICK events, so a reconnecting client rebuilds the whole picture.

Multiline messages

draft/multiline sends a message that spans several lines as one logical message, wrapped in a BATCH; the advertised max-bytes / max-lines limits are configurable.

Web Push

draft/webpush registers an RFC 8291 / 8292 subscription (the WEBPUSH command) so a highlight or private message reaches a client whose tab is backgrounded or away — even when it isn't connected.

STS

sts advertises a strict-transport-security policy on the plaintext port so capable clients upgrade to TLS and pin it for a configured duration.

For SASL mechanisms, see Accounts & SASL.