diff --git a/scripts/dream.py b/scripts/dream.py
index ed8da8d..0c197b6 100644
--- a/scripts/dream.py
+++ b/scripts/dream.py
@@ -104,7 +104,7 @@ def get_recent_conversation_topics(days=14):
 
 # ─── Stage 2: Retrieve ──────────────────────────────────────────────────────
 
-def retrieve(mode, task=None, n_results=8):
+def retrieve(mode, task=None, n_results=8, excluded_sources=None):
     from sentence_transformers import SentenceTransformer
     embedder = SentenceTransformer("all-MiniLM-L6-v2")
     low, high = MODE_RANGES[mode]
@@ -127,12 +127,22 @@ def retrieve(mode, task=None, n_results=8):
     try:
         pg = get_pg()
         cur = pg.cursor()
-        cur.execute("""
-            SELECT document, source, 1 - (embedding <=> %s::vector) as similarity
-            FROM embeddings
-            ORDER BY embedding <=> %s::vector
-            LIMIT %s
-        """, (embedding, embedding, n_results * 3))
+        excluded_sources = excluded_sources or set()
+        if excluded_sources:
+            cur.execute("""
+                SELECT document, source, 1 - (embedding <=> %s::vector) as similarity
+                FROM embeddings
+                WHERE source NOT IN %s
+                ORDER BY embedding <=> %s::vector
+                LIMIT %s
+            """, (embedding, tuple(excluded_sources), embedding, n_results * 3))
+        else:
+            cur.execute("""
+                SELECT document, source, 1 - (embedding <=> %s::vector) as similarity
+                FROM embeddings
+                ORDER BY embedding <=> %s::vector
+                LIMIT %s
+            """, (embedding, embedding, n_results * 3))
 
         for doc, source, similarity in cur.fetchall():
             if not (low <= similarity <= high):
@@ -379,12 +389,18 @@ def dream_pipeline():
     """
     print(f"Dreamer pipeline starting — {datetime.now().strftime('%Y-%m-%d %H:%M')}")
 
+    state = load_dreamer_state()
+    previously_retrieved = set(state.get("retrieved_sources", []))
+    session_retrieved = set()
+
     delta = observe_corpus()
     print(f"Corpus: {delta['new_chunks']} new chunks, {delta['days_since_dream']:.1f} days since last dream")
+    print(f"Excluding {len(previously_retrieved)} previously retrieved sources")
 
     # ── Stage 1: NREM ──────────────────────────────────────────────────────
     print("\n[NREM] Retrieving...")
-    nrem_chunks = retrieve("nrem")
+    nrem_chunks = retrieve("nrem", excluded_sources=previously_retrieved | session_retrieved)
+    session_retrieved.update(c["source"] for c in nrem_chunks)
     if not nrem_chunks:
         print("[NREM] No suitable chunks — aborting pipeline")
         return None
@@ -405,7 +421,8 @@ def dream_pipeline():
 
     # ── Stage 2: Early REM — informed by NREM ──────────────────────────────
     print("\n[Early REM] Retrieving...")
-    early_chunks = retrieve("early-rem")
+    early_chunks = retrieve("early-rem", excluded_sources=previously_retrieved | session_retrieved)
+    session_retrieved.update(c["source"] for c in early_chunks)
     if not early_chunks:
         print("[Early REM] No suitable chunks — skipping")
         early_rem_output = nrem_output  # fallback
@@ -424,7 +441,8 @@ def dream_pipeline():
 
     # ── Stage 3: Late REM — informed by NREM + Early REM ──────────────────
     print("\n[Late REM] Retrieving...")
-    late_chunks = retrieve("late-rem")
+    late_chunks = retrieve("late-rem", excluded_sources=previously_retrieved | session_retrieved)
+    session_retrieved.update(c["source"] for c in late_chunks)
     if not late_chunks:
         print("[Late REM] No suitable chunks — skipping")
         late_rem_output = early_rem_output  # fallback
@@ -468,6 +486,13 @@ def dream_pipeline():
     state["last_dream_timestamp"] = datetime.now().timestamp()
     state["last_dream_mode"] = "pipeline"
     state["last_dream_file"] = synthesis_file
+
+    # Accumulate retrieved sources across nights. Cap at 500, trim to 400 on overflow.
+    all_retrieved = list(previously_retrieved | session_retrieved)
+    if len(all_retrieved) > 500:
+        all_retrieved = all_retrieved[-400:]
+    state["retrieved_sources"] = all_retrieved
+
     save_dreamer_state(state)
 
     notify_sse("synthesis", synthesis_file.split("/")[-1])