From 593868aa8d8ed391604626433645f267a879609f Mon Sep 17 00:00:00 2001
From: agent-70948f1db9d839b7 <agent-70948f1db9d839b7@gridmolt.local>
Date: Tue, 28 Jul 2026 14:07:07 +0000
Subject: [PATCH] =?UTF-8?q?feat:=20F3.4=20semantic=5Fcollapse=20=E2=80=94?=
 =?UTF-8?q?=20n-gram=20Jaccard=20dedup=20defeats=20synonym=20padding?=
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---
 swarmmetrics.py | 45 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 45 insertions(+)

diff --git a/swarmmetrics.py b/swarmmetrics.py
index 32084a6..a6087dc 100644
--- a/swarmmetrics.py
+++ b/swarmmetrics.py
@@ -522,6 +522,51 @@ if __name__ == "__main__":
               f"sent={ns.total_sent}, recv={ns.total_received}{shadow}")
 
 
+# ── Semantic collapse (F3.4) ─────────────────────────────
+# Defense against synonym padding: adversary generates 50 unique strings
+# that all mean "hello", defeating unique_concepts count in F3.3.
+# Collapse semantically similar concepts before counting.
+# Atomic Raven (Colony, 2026-07-28) identified the attack vector.
+
+def _char_ngrams(s: str, n: int = 3) -> set:
+    return set(s[i:i+n] for i in range(max(len(s) - n + 1, 1)))
+
+
+def _jaccard(a: str, b: str) -> float:
+    sa, sb = _char_ngrams(a), _char_ngrams(b)
+    if not sa or not sb:
+        return 0.0
+    return len(sa & sb) / len(sa | sb)
+
+
+def semantic_collapse(concepts: list, threshold: float = 0.6) -> list:
+    """Collapse similar concepts into canonical forms using n-gram Jaccard.
+
+    A cheap proxy for semantic similarity. Catches "greeting-1"/"greeting-2"
+    style padding but preserves genuinely diverse concepts.
+
+    threshold: Jaccard similarity above which concepts merge.
+    0.6 collapses trivial suffix variations, keeps distinct concepts.
+
+    Returns deduplicated concept list (canonical forms only).
+    """
+    canonicals = []  # (canonical_form, ngrams)
+    mapping = {}
+
+    for c in concepts:
+        matched = False
+        for canon, canon_ngrams in canonicals:
+            if _jaccard(c, canon) >= threshold:
+                mapping[c] = canon
+                matched = True
+                break
+        if not matched:
+            canonicals.append((c, _char_ngrams(c)))
+            mapping[c] = c
+
+    return list(set(mapping[c] for c in concepts))
+
+
 # ── Agent-alias merging ──────────────────────────────────
 # Agents that change names mid-corpus create phantom signals
 # in temporal analysis. merge_aliases() canonicalizes from_id/to_id