diff --git a/skills/ingest/scripts/ingest-semantic.py b/skills/ingest/scripts/ingest-semantic.py
index dd974cd..fbd6f18 100644
--- a/skills/ingest/scripts/ingest-semantic.py
+++ b/skills/ingest/scripts/ingest-semantic.py
@@ -142,17 +142,29 @@ paths, slugs, branches, commits or PRs — a deterministic script does all of th
 
 Rules:
 - source_summary: a faithful, self-contained summary of the source, in the
-  source's own language. Plain prose, no markdown headings.
-- key_points: the handful of concrete facts/claims worth indexing.
+  source's own language. Plain prose, NO markdown headings. 2-4 sentences,
+  with concrete details. Preserve the essence and nuance of the source.
+- key_points: 3-5 concrete facts or claims worth indexing; no padding.
 - entities: every person, tool, organisation or product the source names.
-  kind is one of person|tool|org|product. description is one or two factual
-  sentences. No markdown headings inside the description.
+  kind is one of person|tool|org|product. description is 2-3 factual sentences
+  with specifics. No markdown headings inside the description.
 - concepts: every pattern, theory, decision or named idea the source explains.
-  description is one or two factual sentences.
+  description is 2-3 factual sentences with concrete examples or context.
 - contradictions: ONLY when the source makes a claim that directly contradicts a
   widely-known fact or contradicts itself. Otherwise return an empty list.
 - Names must be the natural name of the thing; the script will normalise them.
-Do not pad. Be faithful to the source."""
+
+If the source references an entity or concept already in the wiki (see the list below),
+use the EXACT name already present; do not invent a variant. This prevents duplicates.
+
+Existing entities in this genome:
+{existing_entities}
+
+Existing concepts in this genome:
+{existing_concepts}
+
+Be faithful to the source. Be specific. Do not pad or improvise."""
+
 
 # --- JSON schema -> constrained decoding (Ollama structured outputs) ---
 SCHEMA = {
@@ -195,10 +207,19 @@ SCHEMA = {
 
 
 def call_model():
+    # format existing names as a human-readable list
+    existing_ents = ", ".join(sorted(existing_entities)) or "(none yet)"
+    existing_conc = ", ".join(sorted(existing_concepts)) or "(none yet)"
+
+    prompt = SYSTEM_PROMPT.format(
+        existing_entities=existing_ents,
+        existing_concepts=existing_conc,
+    )
+
     payload = {
         "model": MODEL,
         "messages": [
-            {"role": "system", "content": SYSTEM_PROMPT},
+            {"role": "system", "content": prompt},
             {"role": "user", "content":
                 "Source path: " + raw_rel + "\n\n--- SOURCE START ---\n"
                 + source_text + "\n--- SOURCE END ---\n\nReturn the JSON now."},