diff --git a/src/main.rs b/src/main.rs
index d36ef89..b662f42 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -10,10 +10,11 @@ use matrix_sdk::{
     authentication::matrix::MatrixSession,
     config::SyncSettings,
     ruma::{
-        OwnedEventId, OwnedRoomId, OwnedUserId,
+        OwnedEventId, OwnedRoomId, OwnedUserId, UserId,
         api::client::filter::FilterDefinition,
-        events::room::message::{
-            MessageType, OriginalSyncRoomMessageEvent, RoomMessageEventContent,
+        events::room::{
+            member::StrippedRoomMemberEvent,
+            message::{MessageType, OriginalSyncRoomMessageEvent, RoomMessageEventContent},
         },
     },
 };
@@ -208,11 +209,47 @@ async fn sync(
         }
     });
 
+    client.add_event_handler(on_stripped_state_member);
+
     client.sync(sync_settings).await?;
 
     bail!("sync loop exited unexpectedly")
 }
 
+async fn on_stripped_state_member(event: StrippedRoomMemberEvent, client: Client, room: Room) {
+    let Some(my_id) = client.user_id() else {
+        return;
+    };
+    if event.state_key != my_id {
+        return;
+    }
+    let room_id = room.room_id().to_owned();
+    tokio::spawn(async move {
+        tracing::info!(room = %room_id, "auto-joining invite");
+        let mut delay = 2u64;
+        loop {
+            match room.join().await {
+                Ok(()) => {
+                    tracing::info!(room = %room_id, "joined");
+                    if let Err(e) = ensure_room_notes(&room).await {
+                        tracing::warn!(room = %room_id, "failed to write room notes: {e}");
+                    }
+                    return;
+                }
+                Err(e) => {
+                    tracing::warn!(room = %room_id, "join failed, retry in {delay}s: {e}");
+                    tokio::time::sleep(std::time::Duration::from_secs(delay)).await;
+                    delay = (delay * 2).min(300);
+                    if delay >= 300 {
+                        tracing::error!(room = %room_id, "giving up on auto-join");
+                        return;
+                    }
+                }
+            }
+        }
+    });
+}
+
 async fn persist_sync_token(session_file: &Path, sync_token: String) -> anyhow::Result<()> {
     let data = fs::read_to_string(session_file).await?;
     let mut session: PersistedSession = serde_json::from_str(&data)?;
@@ -234,8 +271,10 @@ async fn on_room_message(
     };
 
     let room_id = room.room_id().to_owned();
-    let mut state = state.lock().await;
-    let is_self = event.sender == state.own_user_id;
+    let is_self = {
+        let state = state.lock().await;
+        event.sender == state.own_user_id
+    };
 
     tracing::info!(
         room = %room_id,
@@ -245,9 +284,102 @@ async fn on_room_message(
         text_content.body
     );
 
-    if !is_self && !state.pending_rooms.contains(&room_id) {
-        state.pending_rooms.push(room_id);
+    if let Err(e) = ensure_room_notes(&room).await {
+        tracing::warn!(room = %room_id, "failed to ensure room notes: {e}");
     }
+    if !is_self {
+        if let Err(e) = ensure_person_notes(&room, &event.sender).await {
+            tracing::warn!(sender = %event.sender, "failed to ensure person notes: {e}");
+        }
+    }
+
+    if !is_self {
+        let mut state = state.lock().await;
+        if !state.pending_rooms.contains(&room_id) {
+            state.pending_rooms.push(room_id);
+        }
+    }
+}
+
+/// Create state/rooms/<room_id>/notes.md if it doesn't exist.
+async fn ensure_room_notes(room: &Room) -> anyhow::Result<()> {
+    let room_id = room.room_id();
+    let dir = paths::state_dir().join("rooms").join(room_id.as_str());
+    let file = dir.join("notes.md");
+    if file.exists() {
+        return Ok(());
+    }
+    fs::create_dir_all(&dir).await?;
+
+    let display_name = room
+        .display_name()
+        .await
+        .map(|n| n.to_string())
+        .unwrap_or_else(|_| room_id.to_string());
+    let now = chrono_now();
+
+    let body = format!("# {room_id}\n\nDisplay name: {display_name}\n\nFirst joined: {now}\n",);
+    fs::write(&file, body).await?;
+    tracing::info!(room = %room_id, "created room notes");
+    Ok(())
+}
+
+/// Create state/people/<user_id>/notes.md if it doesn't exist.
+/// Pre-fill with display name (from this room's member info) and the room as
+/// "first met in".
+async fn ensure_person_notes(room: &Room, user_id: &UserId) -> anyhow::Result<()> {
+    let dir = paths::state_dir().join("people").join(user_id.as_str());
+    let file = dir.join("notes.md");
+    if file.exists() {
+        return Ok(());
+    }
+    fs::create_dir_all(&dir).await?;
+
+    let display_name = room
+        .get_member_no_sync(user_id)
+        .await
+        .ok()
+        .flatten()
+        .and_then(|m| m.display_name().map(ToOwned::to_owned))
+        .unwrap_or_default();
+    let display_line = if display_name.is_empty() {
+        String::new()
+    } else {
+        format!("Display name: {display_name}\n")
+    };
+    let room_id = room.room_id();
+    let now = chrono_now();
+
+    let body = format!("# {user_id}\n\n{display_line}First met in: {room_id} on {now}\n",);
+    fs::write(&file, body).await?;
+    tracing::info!(user = %user_id, "created person notes");
+    Ok(())
+}
+
+fn chrono_now() -> String {
+    use std::time::{SystemTime, UNIX_EPOCH};
+    let secs = SystemTime::now()
+        .duration_since(UNIX_EPOCH)
+        .map(|d| d.as_secs() as i64)
+        .unwrap_or(0);
+    // Simple ISO-ish without pulling chrono. YYYY-MM-DD only is fine for notes.
+    let days = secs / 86400;
+    let (y, m, d) = days_to_ymd(days);
+    format!("{y:04}-{m:02}-{d:02}")
+}
+
+/// Convert days-since-1970-01-01 to (year, month, day). Civil-date algorithm.
+fn days_to_ymd(z: i64) -> (i64, u32, u32) {
+    let z = z + 719_468;
+    let era = z.div_euclid(146_097);
+    let doe = z.rem_euclid(146_097) as u32;
+    let yoe = (doe - doe / 1460 + doe / 36524 - doe / 146_096) / 365;
+    let y = yoe as i64 + era * 400;
+    let doy = doe - (365 * yoe + yoe / 4 - yoe / 100);
+    let mp = (5 * doy + 2) / 153;
+    let d = doy - (153 * mp + 2) / 5 + 1;
+    let m = if mp < 10 { mp + 3 } else { mp - 9 };
+    (if m <= 2 { y + 1 } else { y }, m, d)
 }
 
 async fn process_loop(state: Arc<Mutex<DaemonState>>, client: Client) {