diff --git a/src/main.rs b/src/main.rs
index f9699c3..96aeca9 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -49,6 +49,9 @@ struct ChatMessage {
 struct DaemonState {
     own_user_id: OwnedUserId,
     room_history: std::collections::HashMap<OwnedRoomId, Vec<ChatMessage>>,
+    /// For each room, the index in room_history up to which messages have been
+    /// shown to Claude. Messages at indexes >= this value are "new".
+    seen_count: std::collections::HashMap<OwnedRoomId, usize>,
     pending_rooms: Vec<OwnedRoomId>,
     rate_budget: u32,
     rate_limit_per_min: u32,
@@ -92,6 +95,7 @@ async fn main() -> anyhow::Result<()> {
     let state = Arc::new(Mutex::new(DaemonState {
         own_user_id,
         room_history: std::collections::HashMap::new(),
+        seen_count: std::collections::HashMap::new(),
         pending_rooms: Vec::new(),
         rate_budget: rate_limit_per_min,
         rate_limit_per_min,
@@ -282,20 +286,22 @@ async fn process_loop(state: Arc<Mutex<DaemonState>>, client: Client) {
             continue;
         };
 
-        let history = {
+        let (history, seen_idx) = {
             let state = state.lock().await;
-            state
+            let history = state
                 .room_history
                 .get(&room_id)
                 .cloned()
-                .unwrap_or_default()
+                .unwrap_or_default();
+            let seen = state.seen_count.get(&room_id).copied().unwrap_or(0);
+            (history, seen)
         };
 
         let room_name = client
             .get_room(&room_id)
             .map_or_else(|| room_id.to_string(), |r| r.room_id().to_string());
 
-        match invoke_claude(&room_id, &room_name, &history).await {
+        match invoke_claude(&room_id, &room_name, &history, seen_idx).await {
             Ok(Some(response)) => {
                 if let Some(room) = client.get_room(&response.room) {
                     let content = RoomMessageEventContent::text_plain(&response.body);
@@ -303,6 +309,8 @@ async fn process_loop(state: Arc<Mutex<DaemonState>>, client: Client) {
                         Ok(_) => {
                             let mut state = state.lock().await;
                             state.rate_budget = state.rate_budget.saturating_sub(1);
+                            // Mark current history as seen
+                            state.seen_count.insert(room_id.clone(), history.len());
                             tracing::info!(
                                 room = %response.room,
                                 "sent response ({} budget remaining)",
@@ -317,6 +325,9 @@ async fn process_loop(state: Arc<Mutex<DaemonState>>, client: Client) {
             }
             Ok(None) => {
                 tracing::debug!(room = %room_id, "claude chose to skip");
+                // Even on skip, mark messages as seen so we don't reprocess
+                let mut state = state.lock().await;
+                state.seen_count.insert(room_id.clone(), history.len());
             }
             Err(e) => {
                 tracing::error!(room = %room_id, "claude invocation failed: {e}");
@@ -334,21 +345,43 @@ async fn invoke_claude(
     source_room: &OwnedRoomId,
     room_name: &str,
     history: &[ChatMessage],
+    seen_idx: usize,
 ) -> anyhow::Result<Option<ClaudeResponse>> {
     let identity_dir = paths::identity_dir();
     let identity_str = identity_dir.to_string_lossy();
 
     let mut prompt = String::new();
-    writeln!(prompt, "[room: {source_room} ({room_name})]").unwrap();
-    writeln!(prompt, "[new messages below this line]").unwrap();
+    writeln!(prompt, "[room_id: {source_room}]").unwrap();
+    writeln!(prompt, "[room_name: {room_name}]").unwrap();
+    writeln!(
+        prompt,
+        "[room notes path: ../rooms/{source_room}/notes.md (create dir if needed)]"
+    )
+    .unwrap();
 
-    for msg in history {
-        let prefix = if msg.is_self { "(you) " } else { "" };
-        writeln!(prompt, "{prefix}{}: {}", msg.sender, msg.body).unwrap();
+    let seen = seen_idx.min(history.len());
+    let (old, new) = history.split_at(seen);
+
+    if !old.is_empty() {
+        writeln!(prompt, "\n[previously seen messages — for context]").unwrap();
+        for msg in old {
+            let prefix = if msg.is_self { "(you) " } else { "" };
+            writeln!(prompt, "{prefix}{}: {}", msg.sender, msg.body).unwrap();
+        }
     }
 
-    tracing::info!("invoking claude with {} messages", history.len());
-    tracing::debug!("prompt: {prompt}");
+    writeln!(prompt, "\n[new messages — respond to these]").unwrap();
+    if new.is_empty() {
+        writeln!(prompt, "(none)").unwrap();
+    } else {
+        for msg in new {
+            let prefix = if msg.is_self { "(you) " } else { "" };
+            writeln!(prompt, "{prefix}{}: {}", msg.sender, msg.body).unwrap();
+        }
+    }
+
+    tracing::info!("invoking claude: {} new, {} seen", new.len(), old.len());
+    tracing::trace!("full prompt:\n{prompt}");
 
     use tokio::process::Command;
     let mut cmd = Command::new("claude");