update

backend/learning.py

@@ -269,7 +269,13 @@ def _rating_text(rating: dict) -> str:
 
 # Deterministic guard against double questions — the AI critic misses "…, and which…".
 _QUESTION_WORD = r"(was|welche[rsnm]?|wie|wieso|warum|wofür|wozu|wann|wo|wer|wem|wen|nenne)"
-_DOUBLE_RE = re.compile(r"[,;]?\s+(und|sowie|außerdem|bzw\.?)\s+" + _QUESTION_WORD + r"\b", re.IGNORECASE)
+# Optional preposition between the conjunction and the question word — the second question
+# hides behind it: "und IN welcher Datei", "und UNTER welcher Bedingung".
+_PREP = r"(?:in|unter|auf|für|mit|bei|zu[rm]?|von|vom|über|durch|aus|nach|an|am|um|gegen|ohne|wobei)\s+"
+_DOUBLE_RE = re.compile(
+    r"[,;]?\s+(?:und|sowie|außerdem|bzw\.?)\s+(?:" + _PREP + r")?" + _QUESTION_WORD + r"\b",
+    re.IGNORECASE,
+)
 
 
 def _double_question_flaw(question: str) -> str | None:
@@ -368,9 +374,9 @@ def _avoid_block(avoid: list[str] | None) -> str:
 # the model takes the easy path (mere recall) — the cues lift higher tiers to apply/analyze/transfer.
 TIER_ROLE = {
     "beginner": "The learner is a BEGINNER. Cognitive: REMEMBER/UNDERSTAND. Ask about the basic understanding — the core concept, simple and direct.",
-    "advanced": "The learner is ADVANCED. Cognitive: APPLY. Pose a small concrete situation and have the concept applied to it — don't just ask for the definition.",
-    "expert": "The learner is an EXPERT. Cognitive: ANALYZE. Have them distinguish/compare, classify a special case or uncover a typical pitfall (hurdle) — don't quiz textbook knowledge.",
-    "master": "The learner is at MASTER level. Cognitive: EVALUATE/TRANSFER. Have the concept transferred to a NEW problem, justify a decision or weigh a trade-off.",
+    "advanced": "The learner is ADVANCED. Cognitive: APPLY. Have the concept applied to ONE minimal case — name the case in a half-sentence (no story, no roles, no backstory), then ask ONE single thing.",
+    "expert": "The learner is an EXPERT. Cognitive: ANALYZE. Ask for ONE distinction, comparison, or typical pitfall — a single question, no scenario prose.",
+    "master": "The learner is at MASTER level. Cognitive: EVALUATE/TRANSFER. Have them justify ONE decision or weigh ONE trade-off — one question, no build-up, no second sub-question.",
 }
 
 
@@ -409,18 +415,27 @@ async def exam_question_variant(
     pattern: str, tier: str = "beginner", provider: str = DEFAULT_PROVIDER,
 ) -> str | None:
     """Action 'question' with a pattern: from a predefined pattern, phrase a concrete question in
-    the addressee role of the tier. No critic (the pattern is build-checked).
-    The style guard stays as a cheap protection against double questions · None on error."""
+    the addressee role of the tier. No AI critic (the pattern is build-checked), but the
+    deterministic double-question guard runs and forces a regenerate on a flaw · None on error."""
     try:
         section_block, compact_block = _section_blocks(section, compact)
-        data = await _gen_call(
-            "Block-Question-Variante", "guide", _question_schema, provider, lane="batch",
-            topic=topic, block=block, section_block=section_block,
-            compact_block=compact_block, pattern=pattern, tier_block=_tier_block(tier),
-        )
-        if data is None:
-            return None
-        return data["question"]
+        kritik_block = "(none)"
+        question = None
+        for _ in range(CRITIC_MAX_ROUNDS):
+            data = await _gen_call(
+                "Block-Question-Variante", "guide", _question_schema, provider, lane="batch",
+                topic=topic, block=block, section_block=section_block,
+                compact_block=compact_block, pattern=pattern, tier_block=_tier_block(tier),
+                kritik_block=kritik_block,
+            )
+            if data is None:
+                return None
+            question = data["question"]
+            flaw = _double_question_flaw(question)
+            if not flaw:
+                return question
+            kritik_block = _critique_block(question, [flaw])
+        return question  # best-effort after the last round
     except Exception:
         log.warning("[%s] Question variant failed (%s)", topic, block, exc_info=True)
         return None