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office_translator/services/quality/l2_judge.py
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feat(quality): A4 — L2 Pro premium judge (8 dims, gpt-4o, Pro-gated, opt-in)
2026-07-14 16:56:04 +02:00

396 lines
15 KiB
Python

"""
L2 Pro Premium Judge — stronger model, more dimensions, Pro-tier only.
Why a SEPARATE module from L1?
- L1 is fast + cheap (deepseek-chat, 4 dimensions, 5 samples)
- L2 is slow + expensive (gpt-4o, 8 dimensions, 15 samples)
- Different defaults, different config, different metrics
- L2 is gated to the Pro plan; L1 is universal
L2 dimensions (8):
1. accurate — meaning preserved
2. fluent — natural in target language
3. correct_lang — in the target language (not source leakage)
4. no_leaks — no prompt artifacts
5. terminology — domain terms correctly handled
6. style — appropriate register (formal/informal/technical)
7. completeness — no content dropped or added
8. formatting — codes, numbers, units preserved
L1 was a binary pass/fail. L2 returns per-dimension scores (0/1) so the
caller can decide which dimensions matter for a given job.
DESIGN CONSTRAINTS (same as L1):
- 100% API-based. No local models, no GPU.
- Async, with a hard timeout.
- Defensive: never raises.
- Output is structured JSON.
"""
from __future__ import annotations
import asyncio
import json
import re
import time
from dataclasses import dataclass, field, asdict
from typing import List, Optional, Tuple, Dict, Any
from core.logging import get_logger
logger = get_logger(__name__)
# ---------- Result dataclasses ----------
@dataclass
class L2DimensionVerdict:
"""8-dimension verdict for a single chunk."""
accurate: bool = False
fluent: bool = False
correct_lang: bool = False
no_leaks: bool = False
terminology: bool = False
style: bool = False
completeness: bool = False
formatting: bool = False
reason: str = ""
@property
def passed_count(self) -> int:
return sum([
self.accurate, self.fluent, self.correct_lang, self.no_leaks,
self.terminology, self.style, self.completeness, self.formatting,
])
@property
def total(self) -> int:
return 8
@property
def score(self) -> float:
return self.passed_count / self.total
@property
def passed(self) -> bool:
# L2 is conservative: any single fail = chunk fails
return self.passed_count == self.total
def to_log_dict(self) -> dict:
return asdict(self)
@dataclass
class L2Result:
"""Aggregate result of an L2 check on a sample of chunks."""
verdict: str # "pass", "fail", "skip"
chunks_evaluated: int = 0
chunks_passed: int = 0
chunks_failed: int = 0
failure_rate: float = 0.0
average_score: float = 0.0 # mean of per-chunk scores (0.0 to 1.0)
dimension_pass_rates: Dict[str, float] = field(default_factory=dict)
samples: List[dict] = field(default_factory=list)
model_used: str = ""
elapsed_ms: float = 0.0
cost_estimate_usd: float = 0.0
error: str = ""
def to_log_dict(self) -> dict:
return asdict(self)
# ---------- Prompt template (8 dimensions) ----------
L2_JUDGE_SYSTEM_PROMPT = """You are an expert translation quality evaluator using MQM-inspired criteria.
For each (SOURCE, TRANSLATION) pair, check these 8 criteria (yes/no for each):
1. ACCURATE — Does the translation preserve the meaning of the source?
2. FLUENT — Is the translation natural and grammatical in {target_lang_name}?
3. CORRECT_LANG — Is the translation actually in {target_lang_name} (ISO: {target_lang})?
4. NO_LEAKS — Is the translation free of prompt artifacts, source-language text, or meta-commentary?
5. TERMINOLOGY — Are domain-specific terms (technical, legal, medical, etc.) correctly translated?
6. STYLE — Is the register/tone appropriate (formal/informal/technical matching the source)?
7. COMPLETENESS — Is all content present, with nothing added or dropped?
8. FORMATTING — Are codes, numbers, dates, and units preserved exactly?
A translation FAILS if ANY criterion is "no". The "reason" must be in English and ≤ 20 words.
Respond with a JSON array, one object per pair, in the same order. NO other text, NO markdown fences:
[
{{"accurate": "yes"|"no", "fluent": "yes"|"no", "correct_lang": "yes"|"no", "no_leaks": "yes"|"no", "terminology": "yes"|"no", "style": "yes"|"no", "completeness": "yes"|"no", "formatting": "yes"|"no", "reason": "short justification"}}
]
"""
# ---------- LLM client ----------
class L2ProJudge:
"""
Calls a STRONG LLM via the OpenAI-compatible API to judge translation
quality across 8 dimensions. Pro-tier only.
Default model: gpt-4o (strongest general judge we can afford at scale).
For sub-$0.01/job cost, we limit to 15 samples per job and 8 dimensions.
"""
def __init__(
self,
api_key: str,
base_url: str = "https://api.openai.com/v1",
model: str = "gpt-4o",
timeout_seconds: float = 20.0,
max_retries: int = 1,
):
if not api_key:
raise ValueError("api_key is required for L2ProJudge")
self._api_key = api_key
self._base_url = base_url.rstrip("/")
self._model = model
self._timeout = timeout_seconds
self._max_retries = max_retries
self._client = None
def _get_client(self):
if self._client is None:
try:
import openai
self._client = openai.AsyncOpenAI(
api_key=self._api_key,
base_url=self._base_url,
timeout=self._timeout,
)
except Exception as e:
logger.warning("l2_judge_client_init_failed", error=str(e))
return None
return self._client
async def judge_batch(
self,
pairs: List[Tuple[str, str]],
target_lang: str,
target_lang_name: str = "",
) -> L2Result:
"""
Judge a batch of (source, translation) pairs across 8 dimensions.
Returns an L2Result with verdict="skip" on any internal error.
Never raises.
"""
start = time.time()
empty = L2Result(verdict="skip", error="not_run")
if not pairs:
return L2Result(verdict="skip", error="empty pairs",
elapsed_ms=round((time.time() - start) * 1000, 2))
client = self._get_client()
if client is None:
return L2Result(verdict="skip", error="client unavailable",
elapsed_ms=round((time.time() - start) * 1000, 2))
user_lines = [f"Target language: {target_lang} ({target_lang_name})\n"]
for i, (src, trans) in enumerate(pairs, 1):
user_lines.append(f"\n--- Pair {i} ---")
user_lines.append(f"SOURCE: {src}")
user_lines.append(f"TRANSLATION: {trans}")
user_msg = "\n".join(user_lines)
system_prompt = L2_JUDGE_SYSTEM_PROMPT.format(
target_lang=target_lang,
target_lang_name=target_lang_name or target_lang,
)
try:
response = await asyncio.wait_for(
self._call_with_retries(client, system_prompt, user_msg),
timeout=self._timeout + 5.0,
)
except asyncio.TimeoutError:
elapsed_ms = round((time.time() - start) * 1000, 2)
logger.warning("l2_judge_timeout",
timeout_s=self._timeout, elapsed_ms=elapsed_ms)
return L2Result(verdict="skip", error="timeout", elapsed_ms=elapsed_ms)
except Exception as e:
elapsed_ms = round((time.time() - start) * 1000, 2)
logger.warning("l2_judge_error",
error=str(e)[:200], elapsed_ms=elapsed_ms)
return L2Result(verdict="skip", error=str(e)[:200],
elapsed_ms=elapsed_ms)
verdicts = self._parse_response(response, len(pairs))
if not verdicts:
elapsed_ms = round((time.time() - start) * 1000, 2)
return L2Result(verdict="skip", error="parse_failed",
elapsed_ms=elapsed_ms)
# Aggregate
passed = sum(1 for v in verdicts if v.passed)
failed = len(verdicts) - passed
failure_rate = failed / len(verdicts) if verdicts else 0.0
average_score = sum(v.score for v in verdicts) / len(verdicts)
# Per-dimension pass rates
dimensions = [
"accurate", "fluent", "correct_lang", "no_leaks",
"terminology", "style", "completeness", "formatting",
]
dim_pass_rates = {}
for dim in dimensions:
count = sum(1 for v in verdicts if getattr(v, dim))
dim_pass_rates[dim] = round(count / len(verdicts), 3) if verdicts else 0.0
# L2 verdict: strict — any chunk fail = overall fail
verdict = "pass" if failed == 0 else "fail"
elapsed_ms = round((time.time() - start) * 1000, 2)
cost_estimate = self._estimate_cost(len(pairs))
return L2Result(
verdict=verdict,
chunks_evaluated=len(verdicts),
chunks_passed=passed,
chunks_failed=failed,
failure_rate=round(failure_rate, 3),
average_score=round(average_score, 3),
dimension_pass_rates=dim_pass_rates,
samples=[v.to_log_dict() for v in verdicts],
model_used=self._model,
elapsed_ms=elapsed_ms,
cost_estimate_usd=cost_estimate,
)
async def _call_with_retries(self, client, system_prompt: str, user_msg: str):
"""Call the LLM with retry on transient errors."""
last_exc = None
for attempt in range(self._max_retries + 1):
try:
response = await client.chat.completions.create(
model=self._model,
messages=[
{"role": "system", "content": system_prompt},
{"role": "user", "content": user_msg},
],
temperature=0.0,
max_tokens=1200, # larger than L1 (more dimensions)
response_format={"type": "json_object"},
)
return response
except Exception as e:
last_exc = e
if attempt < self._max_retries:
await asyncio.sleep(0.8)
raise last_exc
def _parse_response(self, response, expected_count: int) -> List[L2DimensionVerdict]:
"""Parse the LLM response into a list of 8-dimension verdicts."""
try:
content = response.choices[0].message.content or ""
except (AttributeError, IndexError) as e:
logger.warning("l2_judge_bad_response", error=str(e))
return []
content = content.strip()
if content.startswith("```"):
content = re.sub(r"^```(?:json)?\s*\n?", "", content)
content = re.sub(r"\n?```\s*$", "", content)
try:
data = json.loads(content)
except json.JSONDecodeError as e:
logger.warning("l2_judge_json_parse_error",
error=str(e), content_preview=content[:200])
return []
if isinstance(data, dict):
items = None
for key in ("verdicts", "results", "translations", "data"):
if key in data and isinstance(data[key], list):
items = data[key]
break
if items is None:
for v in data.values():
if isinstance(v, list):
items = v
break
if items is None:
logger.warning("l2_judge_no_list_in_response")
return []
elif isinstance(data, list):
items = data
else:
logger.warning("l2_judge_unexpected_response_type",
type_=type(data).__name__)
return []
verdicts: List[L2DimensionVerdict] = []
for item in items:
try:
v = L2DimensionVerdict(
accurate=str(item.get("accurate", "")).lower() == "yes",
fluent=str(item.get("fluent", "")).lower() == "yes",
correct_lang=str(item.get("correct_lang", "")).lower() == "yes",
no_leaks=str(item.get("no_leaks", "")).lower() == "yes",
terminology=str(item.get("terminology", "")).lower() == "yes",
style=str(item.get("style", "")).lower() == "yes",
completeness=str(item.get("completeness", "")).lower() == "yes",
formatting=str(item.get("formatting", "")).lower() == "yes",
reason=str(item.get("reason", ""))[:300],
)
verdicts.append(v)
except Exception as e:
logger.warning("l2_judge_item_parse_error",
error=str(e), item=str(item)[:200])
return verdicts
def _estimate_cost(self, num_pairs: int) -> float:
"""Rough USD cost estimate for the call."""
# L2 has more dimensions = longer output
input_tokens = 250 + (num_pairs * 280)
output_tokens = num_pairs * 110
model_lower = self._model.lower()
# IMPORTANT: check 'mini' BEFORE full 'gpt-4o' because
# 'gpt-4o-mini' contains 'gpt-4o'.
if "gpt-4o-mini" in model_lower:
input_cost = input_tokens / 1_000_000 * 0.15
output_cost = output_tokens / 1_000_000 * 0.60
elif "gpt-4o" in model_lower:
input_cost = input_tokens / 1_000_000 * 2.50
output_cost = output_tokens / 1_000_000 * 10.00
elif "claude" in model_lower:
input_cost = input_tokens / 1_000_000 * 3.00
output_cost = output_tokens / 1_000_000 * 15.00
else:
# Generic conservative
input_cost = input_tokens / 1_000_000 * 1.00
output_cost = output_tokens / 1_000_000 * 3.00
return round(input_cost + output_cost, 6)
# ---------- Convenience factory ----------
def make_l2_judge_from_env() -> Optional[L2ProJudge]:
"""
Build an L2ProJudge from environment variables. Returns None if
no API key is configured.
Reads:
- L2_JUDGE_API_KEY (required)
- L2_JUDGE_BASE_URL (default: OpenAI)
- L2_JUDGE_MODEL (default: gpt-4o)
- L2_JUDGE_TIMEOUT (default: 20.0)
"""
import os
api_key = os.getenv("L2_JUDGE_API_KEY", "").strip()
if not api_key:
return None
return L2ProJudge(
api_key=api_key,
base_url=os.getenv("L2_JUDGE_BASE_URL", "https://api.openai.com/v1"),
model=os.getenv("L2_JUDGE_MODEL", "gpt-4o"),
timeout_seconds=float(os.getenv("L2_JUDGE_TIMEOUT", "20.0")),
)