atlasbot: expand keyword tokens

atlasbot/engine/answerer.py

@@ -1464,7 +1464,7 @@ def _needs_evidence_guard(reply: str, facts: list[str]) -> bool:
 def _filter_lines_by_keywords(lines: list[str], keywords: list[str], max_lines: int) -> list[str]:
     if not lines:
         return []
-    tokens = [kw.lower() for kw in keywords if isinstance(kw, str) and kw.strip()]
+    tokens = _expand_tokens(keywords)
     if not tokens:
         return lines[:max_lines]
     filtered = [line for line in lines if any(tok in line.lower() for tok in tokens)]
@@ -1486,7 +1486,7 @@ def _global_facts(lines: list[str]) -> list[str]:
 def _has_keyword_overlap(lines: list[str], keywords: list[str]) -> bool:
     if not lines or not keywords:
         return False
-    tokens = [kw.lower() for kw in keywords if kw]
+    tokens = _expand_tokens(keywords)
     if not tokens:
         return False
     for line in lines:
@@ -1506,6 +1506,21 @@ def _merge_tokens(primary: list[str], secondary: list[str]) -> list[str]:
     return merged
 
 
+def _expand_tokens(tokens: list[str]) -> list[str]:
+    if not tokens:
+        return []
+    expanded: list[str] = []
+    for token in tokens:
+        if not isinstance(token, str):
+            continue
+        for part in re.split(r"[^a-zA-Z0-9_-]+", token.lower()):
+            if len(part) < 3:
+                continue
+            if part not in expanded:
+                expanded.append(part)
+    return expanded
+
+
 def _ensure_token_coverage(
     lines: list[str],
     tokens: list[str],
@@ -1535,7 +1550,7 @@ def _ensure_token_coverage(
 def _best_keyword_line(lines: list[str], keywords: list[str]) -> str | None:
     if not lines or not keywords:
         return None
-    tokens = [kw.lower() for kw in keywords if kw]
+    tokens = _expand_tokens(keywords)
     if not tokens:
         return None
     best = None