tag service replies with +draft/reply and +draft/channel-context

api/src/lib.rs

@@ -19,7 +19,10 @@ pub enum NetEvent {
     // idle half of a routed WHOIS (`WHOIS x x` / mIRC's double-click). Must be
     // answered or that WHOIS produces no output at all.
     Idle { requester: String, target: String },
-    Privmsg { from: String, to: String, text: String },
+    // `msgid` is the uplink's IRCv3 message-id tag on the incoming line, if any —
+    // threaded back onto our replies as `+draft/reply` so a client can group them
+    // under the command that triggered them.
+    Privmsg { from: String, to: String, text: String, msgid: Option<String> },
     UserConnect { uid: String, nick: String, host: String, ip: String },
     // The rest of a user's UID that UserConnect omits — ident, real host, and
     // real name (gecos). The ircd sends them in the same UID line; extban
@@ -132,6 +135,10 @@ pub enum NetAction {
     IntroduceUser { uid: String, nick: String, ident: String, host: String, gecos: String },
     Privmsg { from: String, to: String, text: String },
     Notice { from: String, to: String, text: String },
+    // Wrap another action with IRCv3 client-only message tags (keys begin with
+    // `+`, e.g. `+draft/reply`, `+draft/channel-context`). The serializer prepends
+    // them to each emitted line, or drops them if the uplink can't relay client tags.
+    Tagged { tags: Vec<(String, String)>, inner: Box<NetAction> },
     // An IRCv3 standard reply (FAIL/WARN/NOTE) from a service to a client. Not
     // routable over s2s directly, so it's encapsulated for the target's server
     // (m_services_stdrpl) to re-emit locally, cap-gated. `command`/`from` may be
@@ -591,6 +598,18 @@ macro_rules! plural {
     };
 }
 
+impl NetAction {
+    // The action inside a [`NetAction::Tagged`] wrapper, or this action itself.
+    // Lets an engine transform that rewrites a Notice/Privmsg/StandardReply reach
+    // the real action through any `+draft/…` reply tag it carries.
+    pub fn inner_mut(&mut self) -> &mut NetAction {
+        match self {
+            NetAction::Tagged { inner, .. } => inner,
+            other => other,
+        }
+    }
+}
+
 /// The intent sink a service writes to. A service never mutates the network or
 /// the store itself; it pushes normalized actions (via [`ServiceCtx::notice`]
 /// and friends) that the engine drains and applies.
@@ -614,6 +633,11 @@ pub struct ServiceCtx {
     // preference, else the network default). Set by the engine before dispatch;
     // empty means English. Read via [`ServiceCtx::lang`] / the `t!` macro.
     pub lang: String,
+    // The uid that sent the command being handled, and the IRCv3 msgid of that
+    // line (if the uplink tagged it). A reply going back to `sender_uid` is
+    // threaded with `+draft/reply=<reply_to>`; replies to anyone else are not.
+    pub sender_uid: String,
+    pub reply_to: Option<String>,
 }
 
 // A login-attempt outcome a module hands back for the auth audit feed.
@@ -642,7 +666,32 @@ impl ServiceCtx {
         // unchanged). Interpolated messages must use the `t!` macro so their template
         // — not the already-filled-in text — is the lookup key.
         let text = render(self.lang(), &text.into(), &[]);
-        self.actions.push(NetAction::Notice { from: from.to_string(), to: to.to_string(), text });
+        let inner = NetAction::Notice { from: from.to_string(), to: to.to_string(), text };
+        self.push_tagged(inner, to, Vec::new());
+    }
+
+    // Like [`notice`], but with extra IRCv3 client tags attached (e.g.
+    // `+draft/channel-context=#chan`). The reply-thread tag, if any, is merged in.
+    pub fn notice_tagged(&mut self, from: &str, to: &str, text: impl Into<String>, tags: Vec<(String, String)>) {
+        let text = render(self.lang(), &text.into(), &[]);
+        let inner = NetAction::Notice { from: from.to_string(), to: to.to_string(), text };
+        self.push_tagged(inner, to, tags);
+    }
+
+    // Queue an action, wrapping it in [`NetAction::Tagged`] when there are tags to
+    // carry. A reply to the command's own sender also gets `+draft/reply` so the
+    // client can thread it under the triggering line.
+    fn push_tagged(&mut self, inner: NetAction, to: &str, mut tags: Vec<(String, String)>) {
+        if to == self.sender_uid {
+            if let Some(id) = &self.reply_to {
+                tags.push(("+draft/reply".to_string(), id.clone()));
+            }
+        }
+        self.actions.push(if tags.is_empty() {
+            inner
+        } else {
+            NetAction::Tagged { tags, inner: Box::new(inner) }
+        });
     }
 
     // IRCv3 standard replies from a service (`from` uid) to a client (`to` uid).
@@ -664,14 +713,15 @@ impl ServiceCtx {
 
     fn standard_reply(&mut self, kind: ReplyKind, from: &str, to: &str, command: &str, code: &str, text: impl Into<String>) {
         let text = render(self.lang(), &text.into(), &[]); // auto-localize static replies (see `notice`)
-        self.actions.push(NetAction::StandardReply {
+        let inner = NetAction::StandardReply {
             kind,
             from: from.to_string(),
             to: to.to_string(),
             command: command.to_string(),
             code: code.to_string(),
             text,
-        });
+        };
+        self.push_tagged(inner, to, Vec::new());
     }
 
     // Record a stat counter bump (namespaced, e.g. "chanserv.register"). Folded
@@ -2499,8 +2549,14 @@ pub fn notify_or_memo(ctx: &mut ServiceCtx, net: &dyn NetView, store: &mut dyn S
     if online.is_empty() {
         let _ = store.memo_send(target, by, &text, false);
     } else {
+        // Tag the notice with the channel it's about (`+draft/channel-context`) so a
+        // client can file this "your access changed" line under that channel.
+        let tags: Vec<(String, String)> = args.iter()
+            .find(|(k, _)| *k == "chan")
+            .map(|(_, chan)| vec![("+draft/channel-context".to_string(), chan.clone())])
+            .unwrap_or_default();
         for uid in online {
-            ctx.notice(service, &uid, text.clone());
+            ctx.notice_tagged(service, &uid, text.clone(), tags.clone());
         }
     }
 }

modules/protocol/inspircd/src/lib.rs

@@ -21,11 +21,15 @@ pub struct InspIrcd {
     // consults this so a param-taking mode outside the static fallback table (e.g.
     // m_chanfilter's +g) doesn't desync the param cursor and mispair status/key args.
     chanmodes: std::collections::HashMap<char, echo_api::ChanModeCap>,
+    // Whether the uplink loaded m_ircv3_ctctags (learned from CAPAB MODULES). Only
+    // then can it relay the client-only `+` tags we attach to replies; otherwise we
+    // emit the reply untagged.
+    supports_ctctags: bool,
 }
 
 impl InspIrcd {
     pub fn new(name: String, description: String, sid: String, password: String, protocol: u32, ts: u64, service_modes: String) -> Self {
-        Self { sid, name, description, password, protocol, ts, service_modes, membid: 0, chanmodes: std::collections::HashMap::new() }
+        Self { sid, name, description, password, protocol, ts, service_modes, membid: 0, chanmodes: std::collections::HashMap::new(), supports_ctctags: false }
     }
 
     fn sourced(&self, cmd: String) -> String {
@@ -44,12 +48,14 @@ impl Protocol for InspIrcd {
     }
 
     fn parse(&mut self, line: &str) -> Vec<NetEvent> {
-        // Strip an optional IRCv3 message-tag prefix (@k=v;… ) — insp tags PRIVMSGs
-        // with time/msgid, and it sits before the :source.
-        let line = match line.strip_prefix('@') {
-            Some(rest) => rest.split_once(' ').map(|x| x.1).unwrap_or(""),
-            None => line,
+        // Split off an optional IRCv3 message-tag prefix (@k=v;… ) — insp tags
+        // PRIVMSGs with time/msgid, and it sits before the :source. We keep the
+        // msgid to thread onto our replies (+draft/reply); the rest is parsed as-is.
+        let (tag_prefix, line) = match line.strip_prefix('@') {
+            Some(rest) => rest.split_once(' ').unwrap_or((rest, "")),
+            None => ("", line),
         };
+        let msgid = tag_prefix.split(';').find_map(|kv| kv.strip_prefix("msgid=")).map(str::to_string);
         let (source, rest) = match line.strip_prefix(':') {
             Some(s) => {
                 let mut it = s.splitn(2, ' ');
@@ -119,6 +125,7 @@ impl Protocol for InspIrcd {
                     from: source.unwrap_or_default(),
                     to,
                     text: trailing(rest),
+                    msgid,
                 }]
             }
             // UID <uuid> <nickts> <nick> … — track who's online so services can
@@ -374,6 +381,9 @@ impl Protocol for InspIrcd {
                 // which echo verifies its dependencies against.
                 Some(s) if s.eq_ignore_ascii_case("MODULES") || s.eq_ignore_ascii_case("MODSUPPORT") => {
                     let modules: Vec<_> = trailing(rest).split_whitespace().map(module_name).collect();
+                    if modules.iter().any(|m| m == "ircv3_ctctags") {
+                        self.supports_ctctags = true;
+                    }
                     if modules.is_empty() {
                         vec![]
                     } else {
@@ -425,6 +435,20 @@ impl Protocol for InspIrcd {
             NetAction::Notice { from, to, text } => {
                 split_body(text).into_iter().map(|chunk| format!(":{} NOTICE {} :{}", from, to, chunk)).collect()
             }
+            // Prepend the client tags to each line of the wrapped action — but only
+            // if the uplink can relay them; otherwise emit the inner action untagged.
+            NetAction::Tagged { tags, inner } => {
+                let inner_lines = self.serialize(inner);
+                if !self.supports_ctctags || tags.is_empty() {
+                    inner_lines
+                } else {
+                    let prefix = tags.iter()
+                        .map(|(k, v)| format!("{}={}", k, escape_tag_value(v)))
+                        .collect::<Vec<_>>()
+                        .join(";");
+                    inner_lines.into_iter().map(|l| format!("@{} {}", prefix, l)).collect()
+                }
+            }
             // Standard reply: encapsulate for the target's server to re-emit locally
             // (FAIL/WARN/NOTE aren't s2s-routable). ENCAP * so only the server the
             // target is local to acts. "*" = no source service / no command.
@@ -683,6 +707,23 @@ fn trailing(rest: &str) -> String {
     }
 }
 
+// Escape a value for an IRCv3 message tag (the mandatory five substitutions), so
+// a channel name or msgid carrying a space/semicolon can't break the tag list.
+fn escape_tag_value(v: &str) -> String {
+    let mut out = String::with_capacity(v.len());
+    for c in v.chars() {
+        match c {
+            ';' => out.push_str("\\:"),
+            ' ' => out.push_str("\\s"),
+            '\\' => out.push_str("\\\\"),
+            '\r' => out.push_str("\\r"),
+            '\n' => out.push_str("\\n"),
+            _ => out.push(c),
+        }
+    }
+    out
+}
+
 // A free-text reason param (PART/KICK/QUIT), which the ircd always sends as a
 // `:`-prefixed trailing. Unlike `trailing()`, a MISSING reason yields "" rather
 // than the last preceding word — so `KICK #c target` (no reason) doesn't record
@@ -844,7 +885,7 @@ mod tests {
     fn squery_is_handled_like_privmsg() {
         let mut p = proto();
         assert!(matches!(p.parse(":0IRAAAAAB SQUERY 42SAAAAAB :HELP").as_slice(),
-            [NetEvent::Privmsg { from, to, text }] if from == "0IRAAAAAB" && to == "42SAAAAAB" && text == "HELP"));
+            [NetEvent::Privmsg { from, to, text, .. }] if from == "0IRAAAAAB" && to == "42SAAAAAB" && text == "HELP"));
     }
 
     // CAPAB CAPABILITIES surfaces CASEMAPPING (echo verifies it's ascii).
@@ -993,6 +1034,48 @@ mod tests {
         assert_eq!(without, vec![":42SAAAAAA REDACT alice xyz".to_string()], "no trailing when reason is empty");
     }
 
+    // A tagged reply carries its `+draft/…` tags only after the uplink advertises
+    // m_ircv3_ctctags; before that (or with no tags) it's emitted plain.
+    #[test]
+    fn serializes_tagged_notice_only_when_ctctags_loaded() {
+        let tagged = || NetAction::Tagged {
+            tags: vec![("+draft/reply".to_string(), "abc123".to_string())],
+            inner: Box::new(NetAction::Notice { from: "42SAAAAAA".into(), to: "0IRAAAAAB".into(), text: "hi".into() }),
+        };
+        // No ctctags module -> tags dropped, plain notice.
+        assert_eq!(proto().serialize(&tagged()), vec![":42SAAAAAA NOTICE 0IRAAAAAB :hi".to_string()]);
+        // After CAPAB MODULES lists it -> the tag is prepended.
+        let mut p = proto();
+        p.parse("CAPAB MODULES :account ircv3_ctctags");
+        assert_eq!(p.serialize(&tagged()), vec!["@+draft/reply=abc123 :42SAAAAAA NOTICE 0IRAAAAAB :hi".to_string()]);
+    }
+
+    // Tag values with reserved characters are escaped, and every split line of a
+    // multi-line inner action carries the tags.
+    #[test]
+    fn tagged_values_escaped_and_applied_per_line() {
+        let mut p = proto();
+        p.parse("CAPAB MODULES :ircv3_ctctags");
+        let out = p.serialize(&NetAction::Tagged {
+            tags: vec![("+draft/channel-context".to_string(), "#a b".to_string())],
+            inner: Box::new(NetAction::Notice { from: "42SAAAAAA".into(), to: "0IRAAAAAB".into(), text: "word ".repeat(200).trim().to_string() }),
+        });
+        assert!(out.len() >= 2, "long notice split into multiple lines");
+        assert!(out.iter().all(|l| l.starts_with("@+draft/channel-context=#a\\sb :")), "every line tagged + escaped: {out:?}");
+    }
+
+    // insp tags an incoming PRIVMSG with a msgid; we capture it so the reply can
+    // thread against it.
+    #[test]
+    fn parses_msgid_from_privmsg_tags() {
+        let ev = proto().parse("@msgid=xyz789;time=2026-01-01T00:00:00Z :0IRAAAAAB PRIVMSG 42SAAAAAB :HELP");
+        assert!(matches!(ev.as_slice(),
+            [NetEvent::Privmsg { msgid: Some(m), text, .. }] if m == "xyz789" && text == "HELP"));
+        // No tag prefix -> no msgid.
+        let ev = proto().parse(":0IRAAAAAB PRIVMSG 42SAAAAAB :HELP");
+        assert!(matches!(ev.as_slice(), [NetEvent::Privmsg { msgid: None, .. }]));
+    }
+
     #[test]
     fn serializes_svspart() {
         let lines = proto().serialize(&NetAction::ForcePart { uid: "0IRAAAAAB".into(), channel: "#chan".into(), reason: "bye".into() });

src/engine/dispatch.rs

@@ -36,14 +36,14 @@ impl Engine {
 
     // Route a PRIVMSG addressed to a service (by uid or nick) into that service,
     // handing it the sender's resolved nick, login state, and the account store.
-    pub(crate) fn dispatch(&mut self, from: &str, to: &str, text: &str) -> Vec<NetAction> {
+    pub(crate) fn dispatch(&mut self, from: &str, to: &str, text: &str, msgid: Option<String>) -> Vec<NetAction> {
         let nick = self.network.nick_of(from).unwrap_or(from).to_string();
         let account = self.network.account_of(from).map(str::to_string);
         let privs = account.as_deref().map(|a| self.oper_privs(a)).unwrap_or_default();
         // Render this command's replies in the sender's language: their account
         // preference if set, otherwise the network default.
         let lang = account.as_deref().and_then(|a| self.db.language_of(a)).unwrap_or_else(|| self.db.default_language());
-        let mut ctx = ServiceCtx { lang, ..Default::default() };
+        let mut ctx = ServiceCtx { lang, sender_uid: from.to_string(), reply_to: msgid, ..Default::default() };
         // Mark the log so we can tell exactly which events this command appends.
         let audit_mark = self.db.log_len();
         let sender = Sender { uid: from, nick: &nick, account: account.as_deref(), privs };
@@ -194,7 +194,7 @@ impl Engine {
     fn apply_msg_style(&self, out: &mut [NetAction]) {
         let mut named: std::collections::HashSet<(String, String)> = std::collections::HashSet::new();
         for a in out.iter_mut() {
-            let NetAction::Notice { from, to, text } = a else { continue };
+            let NetAction::Notice { from, to, text } = a.inner_mut() else { continue };
             let Some(account) = self.network.account_of(to) else { continue };
             if !self.db.account_wants_snotice(account) {
                 continue;
@@ -230,8 +230,9 @@ impl Engine {
             self.route_to(&dsuid, sender, &args, ctx);
             // Turn DiceServ's private notices into the bot speaking to the channel.
             for a in ctx.actions[mark..].iter_mut() {
-                if let NetAction::Notice { text, .. } = a {
-                    *a = NetAction::Privmsg { from: botuid.clone(), to: chan.to_string(), text: std::mem::take(text) };
+                let slot = a.inner_mut();
+                if let NetAction::Notice { text, .. } = slot {
+                    *slot = NetAction::Privmsg { from: botuid.clone(), to: chan.to_string(), text: std::mem::take(text) };
                 }
             }
             return;
@@ -265,11 +266,12 @@ impl Engine {
         // Fantasy is public: the bot speaks ChanServ's text replies into the channel,
         // and its actions (modes, kicks) are re-sourced from the bot.
         for a in ctx.actions[mark..].iter_mut() {
-            match a {
+            let slot = a.inner_mut();
+            match slot {
                 NetAction::Notice { text, .. } => {
-                    *a = NetAction::Privmsg { from: botuid.clone(), to: chan.to_string(), text: std::mem::take(text) };
+                    *slot = NetAction::Privmsg { from: botuid.clone(), to: chan.to_string(), text: std::mem::take(text) };
                 }
-                _ => resource_action(a, &csuid, &botuid),
+                _ => resource_action(slot, &csuid, &botuid),
             }
         }
     }

src/engine/mod.rs

@@ -1638,7 +1638,7 @@ impl Engine {
                 }
                 Vec::new()
             }
-            NetEvent::Privmsg { from, to, text } => self.dispatch(&from, &to, &text),
+            NetEvent::Privmsg { from, to, text, msgid } => self.dispatch(&from, &to, &text, msgid),
             NetEvent::AccountRequest { reqid, origin, kind, account, p2, p3 } => {
                 self.account_request(reqid, origin, kind, account, p2, p3)
             }
@@ -1688,13 +1688,14 @@ impl Engine {
     // (or `*** text` when there's no command), sourced from the same service.
     fn degrade_standard_replies(&self, actions: &mut [NetAction]) {
         for a in actions.iter_mut() {
-            if let NetAction::StandardReply { from, to, command, text, .. } = a {
+            let slot = a.inner_mut();
+            if let NetAction::StandardReply { from, to, command, text, .. } = slot {
                 let body = if command.is_empty() || command == "*" {
                     format!("*** {text}")
                 } else {
                     format!("*** {command}: {text}")
                 };
-                *a = NetAction::Notice { from: std::mem::take(from), to: std::mem::take(to), text: body };
+                *slot = NetAction::Notice { from: std::mem::take(from), to: std::mem::take(to), text: body };
             }
         }
     }
@@ -2073,7 +2074,7 @@ fn audit_summary(event: &db::Event) -> Option<String> {
 // Rewrite the source uid of an action from `old` to `new`, where the variant
 // carries a `from`. Used to make fantasy output appear to come from the bot.
 fn resource_action(a: &mut NetAction, old: &str, new: &str) {
-    let from = match a {
+    let from = match a.inner_mut() {
         NetAction::Notice { from, .. }
         | NetAction::Privmsg { from, .. }
         | NetAction::ChannelMode { from, .. }