hive-matrix-mcp: an edited message shows once, edited in place, and is not a second unread

docs/2-handbook/tools/matrix.md

@@ -27,7 +27,10 @@ is what an agent reads at call time. They fall into four groups:
 - **Reading:** `read_room`, `download_file`, `list_rooms` and
   `list_room_members`. `read_room` shows media as `[file: …]`, `[image: …]`,
   `[audio: …]` or `[video: …]` markers, and the event id of one goes to
-  `download_file`.
+  `download_file`. An edited message shows once, with its latest text and
+  `edited: true`. The edit event doesn't appear as a second message and doesn't
+  count as unread. When the original is outside the window read, the edit stays
+  as its own event, and its `replaces_event_id` names the message it replaces.
 - **Room membership:** `invite_user`, `list_invites`, `resolve_invite` and
   `join_room`. `resolve_invite` accepts or rejects a pending invite and is the
   path for invites; `join_room` is for a public room the agent wasn't invited to.

hive-matrix-mcp/src/handlers.rs

@@ -77,6 +77,73 @@ pub struct TimelineEvent {
     /// carries. `None` for top-level (non-reply) messages.
     #[serde(skip_serializing_if = "Option::is_none")]
     pub in_reply_to_event_id: Option<String>,
+    /// Set on a message that was edited: `body` then holds the latest
+    /// edited text, not the text first posted.
+    #[serde(skip_serializing_if = "std::ops::Not::not")]
+    pub edited: bool,
+    /// Set on an edit (`m.replace`) event whose original is outside the
+    /// window read: the id of the message it replaces, with `body` holding
+    /// the new text. Edits whose original is in the window are folded into
+    /// it by `collapse_edits` and never appear on their own.
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub replaces_event_id: Option<String>,
+}
+
+/// The `(replaced event id, new body)` an edit (`m.replace`) event
+/// carries, or `None` for any other event. The top-level `body` of an edit
+/// is a `* `-prefixed fallback for clients that cannot render edits; the
+/// text to show is in `m.new_content`.
+fn replacement_of(
+    event: &matrix_sdk::ruma::events::AnySyncTimelineEvent,
+) -> Option<(String, String)> {
+    use matrix_sdk::ruma::events::room::message::Relation;
+    use matrix_sdk::ruma::events::{AnySyncMessageLikeEvent, AnySyncTimelineEvent};
+    let AnySyncTimelineEvent::MessageLike(AnySyncMessageLikeEvent::RoomMessage(ev)) = event else {
+        return None;
+    };
+    match ev.as_original()?.content.relates_to.as_ref()? {
+        Relation::Replacement(r) => Some((
+            r.event_id.to_string(),
+            attachment_marker(&r.new_content.msgtype),
+        )),
+        _ => None,
+    }
+}
+
+/// Fold each edit into the message it replaces, so a reader sees the
+/// edited text once instead of the original plus a `* ` duplicate.
+/// `events` is newest first, so the first edit met for a message is its
+/// latest. An edit only counts when its sender also sent the original
+/// (the spec's rule); one whose original is outside the window stays as an
+/// event of its own with `replaces_event_id` set.
+fn collapse_edits(events: Vec<TimelineEvent>) -> Vec<TimelineEvent> {
+    let mut latest: std::collections::HashMap<String, String> = std::collections::HashMap::new();
+    let mut folded: std::collections::HashSet<String> = std::collections::HashSet::new();
+    for edit in &events {
+        let Some(target) = &edit.replaces_event_id else {
+            continue;
+        };
+        let original_by_same_sender = events
+            .iter()
+            .any(|e| &e.event_id == target && e.sender == edit.sender);
+        if original_by_same_sender {
+            folded.insert(edit.event_id.clone());
+            latest
+                .entry(target.clone())
+                .or_insert_with(|| edit.body.clone());
+        }
+    }
+    events
+        .into_iter()
+        .filter(|e| !folded.contains(&e.event_id))
+        .map(|mut e| {
+            if let Some(body) = latest.remove(&e.event_id) {
+                e.body = body;
+                e.edited = true;
+            }
+            e
+        })
+        .collect()
 }
 
 /// Resolve a room reference (id `!abc:server` OR alias `#name:server`)
@@ -231,18 +298,21 @@ async fn recent_events(
 /// (of every msgtype, not just `m.room.message`'s common ones),
 /// reactions, state changes (join/leave/topic/name/etc. are all real
 /// activity an agent should see, mara: don't lump them in with
-/// housekeeping noise). The one deliberate exception is `m.space.child`:
+/// housekeeping noise). The deliberate exceptions are `m.space.child`:
 /// a periodic re-apply of an *unchanged* value still appends a timeline
 /// event (see [`room_unread_state`]'s doc comment), and that specific
-/// redundant re-emit is the one thing this function exists to filter —
+/// redundant re-emit is the thing this function exists to filter —
 /// an earlier version of this filter over-corrected by excluding whole
-/// event categories instead of just that one type; narrower is right.
+/// event categories instead of just that one type; narrower is right —
+/// and an edit (`m.replace`), which restates a message already counted.
 fn is_intentional(event: &matrix_sdk::ruma::events::AnySyncTimelineEvent) -> bool {
     use matrix_sdk::ruma::events::{AnySyncStateEvent, AnySyncTimelineEvent};
+    // An edit (`m.replace`) is the same message again, not a new one: it
+    // must not count as a second unread (which would also hold up sends).
     !matches!(
         event,
         AnySyncTimelineEvent::State(AnySyncStateEvent::SpaceChild(_))
-    )
+    ) && replacement_of(event).is_none()
 }
 
 /// Whether `room` carries content the agent hasn't caught up on.
@@ -890,8 +960,11 @@ fn to_timeline_event(
     is_encrypted: bool,
 ) -> Option<TimelineEvent> {
     let parsed = ev.raw().deserialize().ok()?;
+    let replacement = replacement_of(&parsed);
     let body = if is_encrypted && ev.kind.is_utd() {
         "[unable to decrypt]".to_owned()
+    } else if let Some((_, new_body)) = &replacement {
+        new_body.clone()
     } else {
         extract_body_sync(&parsed)
     };
@@ -902,6 +975,8 @@ fn to_timeline_event(
         event_type: parsed.event_type().to_string(),
         body,
         in_reply_to_event_id: extract_in_reply_to(&parsed),
+        edited: false,
+        replaces_event_id: replacement.map(|(target, _)| target),
     })
 }
 
@@ -1028,7 +1103,7 @@ pub async fn read_room(
             .filter_map(|ev| to_timeline_event(ev, is_encrypted))
             .collect()
     };
-    DaemonResponse::ok(&events)
+    DaemonResponse::ok(&collapse_edits(events))
 }
 
 /// Download the media attachment carried by `event_id` in `room` and
@@ -1222,8 +1297,8 @@ mod utd_body_tests {
 #[cfg(test)]
 mod unread_tests {
     use super::{
-        ParsedEvent, attachment_marker, extract_body_sync, extract_in_reply_to, is_intentional,
+        ParsedEvent, TimelineEvent, attachment_marker, collapse_edits, extract_body_sync,
-        unread_verdict,
+        extract_in_reply_to, is_intentional, replacement_of, unread_verdict,
     };
     use matrix_sdk::ruma::events::AnySyncTimelineEvent;
     use matrix_sdk::ruma::events::room::message::MessageType;
@@ -1311,6 +1386,153 @@ mod unread_tests {
         assert_eq!(verdict(None, &events), None);
     }
 
+    fn edit(id: &str, sender: &str, target: &str, new_body: &str) -> AnySyncTimelineEvent {
+        parse(json!({
+            "type": "m.room.message",
+            "event_id": id,
+            "sender": sender,
+            "origin_server_ts": 2,
+            "content": {
+                "msgtype": "m.text",
+                "body": format!("* {new_body}"),
+                "m.new_content": {"msgtype": "m.text", "body": new_body},
+                "m.relates_to": {"rel_type": "m.replace", "event_id": target},
+            },
+        }))
+    }
+
+    fn timeline(id: &str, sender: &str, body: &str, replaces: Option<&str>) -> TimelineEvent {
+        TimelineEvent {
+            event_id: id.into(),
+            sender: sender.into(),
+            origin_server_ts: 1,
+            event_type: "m.room.message".into(),
+            body: body.into(),
+            in_reply_to_event_id: None,
+            edited: false,
+            replaces_event_id: replaces.map(Into::into),
+        }
+    }
+
+    #[test]
+    fn an_edit_carries_the_new_text_and_the_id_it_replaces() {
+        let ev = edit(
+            "$e:example.org",
+            "@bob:example.org",
+            "$o:example.org",
+            "fixed",
+        );
+        assert_eq!(
+            replacement_of(&ev),
+            Some(("$o:example.org".into(), "fixed".into()))
+        );
+        assert_eq!(
+            replacement_of(&message("$m:example.org", "@bob:example.org", "plain")),
+            None
+        );
+    }
+
+    #[test]
+    fn an_edit_is_not_a_second_unread_message() {
+        assert!(!is_intentional(&edit(
+            "$e:example.org",
+            "@bob:example.org",
+            "$o:example.org",
+            "fixed"
+        )));
+        // The edit sits newest; the walk skips it and lands on the
+        // original, so the room reports one unread message, not two.
+        let events = [
+            Some(live(edit(
+                "$e:example.org",
+                "@bob:example.org",
+                "$o:example.org",
+                "fixed",
+            ))),
+            Some(live(message("$o:example.org", "@bob:example.org", "typo"))),
+        ];
+        assert_eq!(
+            verdict(None, &events).map(|(id, _, _)| id),
+            Some("$o:example.org".into())
+        );
+    }
+
+    #[test]
+    fn an_edit_folds_into_its_original_and_the_duplicate_disappears() {
+        let got = collapse_edits(vec![
+            timeline(
+                "$e:example.org",
+                "@bob:example.org",
+                "fixed",
+                Some("$o:example.org"),
+            ),
+            timeline("$other:example.org", "@amy:example.org", "unrelated", None),
+            timeline("$o:example.org", "@bob:example.org", "typo", None),
+        ]);
+        let ids: Vec<&str> = got.iter().map(|e| e.event_id.as_str()).collect();
+        assert_eq!(ids, ["$other:example.org", "$o:example.org"]);
+        assert_eq!(got[1].body, "fixed");
+        assert!(got[1].edited);
+        assert!(!got[0].edited);
+    }
+
+    #[test]
+    fn the_latest_of_several_edits_wins() {
+        let got = collapse_edits(vec![
+            timeline(
+                "$e2:example.org",
+                "@bob:example.org",
+                "third",
+                Some("$o:example.org"),
+            ),
+            timeline(
+                "$e1:example.org",
+                "@bob:example.org",
+                "second",
+                Some("$o:example.org"),
+            ),
+            timeline("$o:example.org", "@bob:example.org", "first", None),
+        ]);
+        assert_eq!(got.len(), 1);
+        assert_eq!(got[0].body, "third");
+    }
+
+    #[test]
+    fn someone_elses_edit_does_not_rewrite_a_message() {
+        let got = collapse_edits(vec![
+            timeline(
+                "$e:example.org",
+                "@mallory:example.org",
+                "forged",
+                Some("$o:example.org"),
+            ),
+            timeline("$o:example.org", "@bob:example.org", "real", None),
+        ]);
+        assert_eq!(
+            got.len(),
+            2,
+            "the forged edit stays visible as its own event"
+        );
+        assert_eq!(got[1].body, "real");
+        assert!(!got[1].edited);
+    }
+
+    #[test]
+    fn an_edit_whose_original_is_out_of_the_window_stays_and_says_what_it_replaces() {
+        let got = collapse_edits(vec![timeline(
+            "$e:example.org",
+            "@bob:example.org",
+            "fixed",
+            Some("$old:example.org"),
+        )]);
+        assert_eq!(got.len(), 1);
+        assert_eq!(
+            got[0].replaces_event_id.as_deref(),
+            Some("$old:example.org")
+        );
+        assert_eq!(got[0].body, "fixed");
+    }
+
     #[test]
     fn a_space_child_re_emit_is_skipped_to_reach_the_real_message() {
         let events = [

hive-matrix-mcp/src/mcp.rs

@@ -462,7 +462,10 @@ impl MatrixMcp {
     #[tool(description = "Read events from a matrix room (default 50, max 200), \
             newest first. Returns each event's id, sender, timestamp, type, \
             best-effort plain-text body, and the id of the event it replies to \
-            (when any). By default returns the most recent events. Pass `from` \
+            (when any). An edited message appears once with its latest text and \
+            `edited: true`; the edit event itself is folded in, not listed (one \
+            whose original is outside the window stays, with `replaces_event_id`). \
+            By default returns the most recent events. Pass `from` \
             = an event id to read forward from that event (anchor + newer \
             events), or `until` = an event id to read backward to it (anchor + \
             older events) — e.g. to fetch the context around a reply target \