Livrare LOT 1 - Didi

ai_platform/modules/didi_brain/lint/detector.py

@@ -0,0 +1,114 @@
+"""Single-pair NLI classification for the Lint pass.
+
+Takes two claim texts and asks Qwen 397B whether they are EQUIVALENT,
+CONTRADICTORY, or INCOMPARABLE. Returns a dataclass with label +
+confidence + optional error. Never raises — all failure paths fall
+through to INCOMPARABLE with an error string.
+"""
+
+from __future__ import annotations
+
+import asyncio
+from dataclasses import dataclass
+from pathlib import Path
+
+from shared.config import LlmRole
+from shared.llm_client import LlmClient, LlmError
+from shared.logging import get_logger
+
+log = get_logger(__name__)
+
+PROMPT_VERSION = "v1"
+_PROMPT_PATH = (
+    Path(__file__).resolve().parent / "prompts" / f"pair_nli_{PROMPT_VERSION}.md"
+)
+
+ALLOWED_LABELS = {"EQUIVALENT", "CONTRADICTORY", "INCOMPARABLE"}
+MAX_CLAIM_CHARS = 1500      # truncate long evidence before sending to LLM
+PER_CALL_TIMEOUT_S = 30.0
+
+
+_PROMPT: str | None = None
+
+
+def _load_prompt() -> str:
+    global _PROMPT
+    if _PROMPT is None:
+        _PROMPT = _PROMPT_PATH.read_text(encoding="utf-8")
+    return _PROMPT
+
+
+@dataclass(slots=True, frozen=True)
+class PairClassification:
+    label: str
+    confidence: float
+    error: str | None = None
+
+
+async def classify_pair(
+    llm: LlmClient,
+    *,
+    claim_a: str,
+    claim_b: str,
+    timeout_s: float = PER_CALL_TIMEOUT_S,
+) -> PairClassification:
+    if not claim_a.strip() or not claim_b.strip():
+        return PairClassification(
+            label="INCOMPARABLE", confidence=0.0, error="empty_claim"
+        )
+
+    prompt = (
+        _load_prompt()
+        .replace("{claim_a}", claim_a[:MAX_CLAIM_CHARS])
+        .replace("{claim_b}", claim_b[:MAX_CLAIM_CHARS])
+    )
+
+    try:
+        result, _usage = await asyncio.wait_for(
+            llm.chat_json(
+                role=LlmRole.REASONING,
+                system=(
+                    "You are a precise claim comparison classifier. "
+                    "Respond with strictly valid JSON only, no commentary."
+                ),
+                user=prompt,
+                max_tokens=120,
+                temperature=0.0,
+            ),
+            timeout=timeout_s,
+        )
+    except asyncio.TimeoutError:
+        return PairClassification(
+            label="INCOMPARABLE", confidence=0.0, error="timeout"
+        )
+    except LlmError as e:
+        return PairClassification(
+            label="INCOMPARABLE", confidence=0.0, error=f"llm:{e}"
+        )
+    except Exception as e:  # noqa: BLE001
+        return PairClassification(
+            label="INCOMPARABLE",
+            confidence=0.0,
+            error=f"{type(e).__name__}:{e}",
+        )
+
+    if not isinstance(result, dict):
+        return PairClassification(
+            label="INCOMPARABLE", confidence=0.0, error="non_dict_response"
+        )
+
+    raw_label = (result.get("label") or "").strip().upper()
+    try:
+        conf = float(result.get("confidence", 0))
+    except (TypeError, ValueError):
+        conf = 0.0
+    conf = max(0.0, min(1.0, conf))
+
+    if raw_label not in ALLOWED_LABELS:
+        return PairClassification(
+            label="INCOMPARABLE",
+            confidence=0.0,
+            error=f"bad_label:{raw_label[:40]}",
+        )
+
+    return PairClassification(label=raw_label, confidence=conf)