{ "evaluation_id": "EVAL-20260402-121140", "question_id": "CODE-001", "question_text": "This Python async function has 3 bugs: a race condition, an unhandled exception, and a resource leak. Find all three and explain why each is problematic.\n\n```python\nimport asyncio\nimport aiohttp\n\nclass DataFetcher:\n def __init__(self):\n self.cache = {}\n self.session = aiohttp.ClientSession()\n \n async def fetch_data(self, urls):\n results = []\n for url in urls:\n if url in self.cache:\n results.append(self.cache[url])\n else:\n async with self.session.get(url) as response:\n data = await response.json()\n self.cache[url] = data\n results.append(data)\n return results\n \n async def fetch_parallel(self, urls):\n tasks = [self.fetch_single(url) for url in urls]\n return await asyncio.gather(*tasks)\n \n async def fetch_single(self, url):\n if url in self.cache:\n return self.cache[url]\n async with self.session.get(url) as response:\n data = await response.json()\n self.cache[url] = data\n return data\n```", "category": "code", "timestamp": "2026-01-13T00:00:00.000Z", "display_date": "Jan 13, 2026", "winner": { "name": "Grok 4.20", "provider": "openrouter", "score": 9.44 }, "avg_score": 8.51, "matrix_size": 86, "models_used": [ { "id": "claude_opus_46", "name": "Claude Opus 4.6", "provider": "openrouter" }, { "id": "gemini_31_pro", "name": "Gemini 3.1 Pro", "provider": "openrouter" }, { "id": "claude_sonnet_46", "name": "Claude Sonnet 4.6", "provider": "openrouter" }, { "id": "grok_420", "name": "Grok 4.20", "provider": "openrouter" }, { "id": "deepseek_v4", "name": "DeepSeek V4", "provider": "openrouter" }, { "id": "gpt_oss_120b", "name": "GPT-OSS-120B", "provider": "OpenAI" }, { "id": "gemini_3_flash", "name": "Gemini 3 Flash Preview", "provider": "Google" }, { "id": "minimax_m25", "name": "MiniMax M2.5", "provider": "openrouter" }, { "id": "mimo_v2_flash", "name": "MiMo-V2-Flash", "provider": "Xiaomi" }, { "id": "gpt_5_4", "name": "GPT-5.4", "provider": "openrouter" } ], "rankings": { "grok_420": { "display_name": "Grok 4.20", "provider": "openrouter", "average_score": 9.44, "score_count": 9, "min_score": 8.95, "max_score": 10, "rank": 1 }, "claude_opus_46": { "display_name": "Claude Opus 4.6", "provider": "openrouter", "average_score": 9.33, "score_count": 9, "min_score": 8.35, "max_score": 10, "rank": 2 }, "claude_sonnet_46": { "display_name": "Claude Sonnet 4.6", "provider": "openrouter", "average_score": 9.32, "score_count": 9, "min_score": 7.95, "max_score": 10, "rank": 3 }, "gemini_3_flash": { "display_name": "Gemini 3 Flash Preview", "provider": "Google", "average_score": 9.27, "score_count": 9, "min_score": 8.6, "max_score": 10, "rank": 4 }, "gpt_5_4": { "display_name": "GPT-5.4", "provider": "openrouter", "average_score": 9.13, "score_count": 9, "min_score": 8.45, "max_score": 9.8, "rank": 5 }, "mimo_v2_flash": { "display_name": "MiMo-V2-Flash", "provider": "Xiaomi", "average_score": 8.93, "score_count": 9, "min_score": 6.75, "max_score": 10, "rank": 6 }, "gemini_31_pro": { "display_name": "Gemini 3.1 Pro", "provider": "openrouter", "average_score": 8.76, "score_count": 9, "min_score": 8.05, "max_score": 10, "rank": 7 }, "deepseek_v4": { "display_name": "DeepSeek V4", "provider": "openrouter", "average_score": 8.68, "score_count": 9, "min_score": 7.85, "max_score": 10, "rank": 8 }, "minimax_m25": { "display_name": "MiniMax M2.5", "provider": "openrouter", "average_score": 7.93, "score_count": 9, "min_score": 6.25, "max_score": 9.6, "rank": 9 }, "gpt_oss_120b": { "display_name": "GPT-OSS-120B", "provider": "OpenAI", "average_score": 4.31, "score_count": 5, "min_score": 0.25, "max_score": 8.8, "rank": 10 } }, "judgments": [ { "judge_key": "gpt_5_4", "judge_name": "GPT-5.4", "respondent_key": "claude_opus_46", "respondent_name": "Claude Opus 4.6", "weighted_score": 8.8, "brief_justification": "Accurately identifies the cache race, unhandled network/JSON exception path, and unclosed ClientSession leak. Explanations are clear and practical, with good fixes. Minor nit: saying distinct URLs make shared-state access unsafe overstates the specific race, and the gather-cancels-all wording is slightly imprecise." }, { "judge_key": "gpt_5_4", "judge_name": "GPT-5.4", "respondent_key": "gemini_31_pro", "respondent_name": "Gemini 3.1 Pro", "weighted_score": 8.3, "brief_justification": "Accurately identifies the race condition, missing exception handling, and unclosed ClientSession. Explanations are clear and technically sound. Slightly incomplete because the response is truncated before fully finishing the resource leak discussion and fixes." }, { "judge_key": "gpt_5_4", "judge_name": "GPT-5.4", "respondent_key": "claude_sonnet_46", "respondent_name": "Claude Sonnet 4.6", "weighted_score": 9, "brief_justification": "Accurately identifies the cache race, missing session cleanup, and exception propagation around HTTP/JSON handling. Explanation is clear and practical, with solid fixes and good async-specific detail. Minor overstatement around gather cancelling siblings and event-loop creation nuance keeps it from perfect." }, { "judge_key": "gpt_5_4", "judge_name": "GPT-5.4", "respondent_key": "grok_420", "respondent_name": "Grok 4.20", "weighted_score": 9, "brief_justification": "Accurately identifies the session leak, cache race, and lack of exception handling, with clear explanations and practical fixes. Minor nit: saying async with ClientSession in __init__ is tricky is imprecise, but overall the analysis is strong and complete." }, { "judge_key": "gpt_5_4", "judge_name": "GPT-5.4", "respondent_key": "deepseek_v4", "respondent_name": "DeepSeek V4", "weighted_score": 7.85, "brief_justification": "Correctly identifies the race condition, missing exception handling, and unclosed ClientSession. Explanation is clear and mostly accurate. Minor issues: claiming unhandled async exceptions may terminate the entire event loop is overstated, and the proposed lock-based fix is too coarse and paired with gather(return_exceptions=True), which changes semantics rather than directly fixing the original bug." }, { "judge_key": "gpt_5_4", "judge_name": "GPT-5.4", "respondent_key": "gpt_oss_120b", "respondent_name": "GPT-OSS-120B", "weighted_score": 0.25, "brief_justification": "No response was provided to evaluate, so it does not identify any bugs or offer any explanation." }, { "judge_key": "gpt_5_4", "judge_name": "GPT-5.4", "respondent_key": "gemini_3_flash", "respondent_name": "Gemini 3 Flash Preview", "weighted_score": 8.6, "brief_justification": "Accurately identifies the cache race, unclosed ClientSession leak, and gather exception propagation, with clear explanations and practical fixes. Slightly overstated example details like treating 404 as an exception by default, and could mention cancellation behavior or response status handling for fuller completeness." }, { "judge_key": "gpt_5_4", "judge_name": "GPT-5.4", "respondent_key": "minimax_m25", "respondent_name": "MiniMax M2.5", "weighted_score": 6.65, "brief_justification": "Correctly identifies the resource leak and cache race condition, but the response is truncated and does not fully cover the unhandled exception bug. It is clear and reasonably explained, but incomplete." }, { "judge_key": "gpt_5_4", "judge_name": "GPT-5.4", "respondent_key": "mimo_v2_flash", "respondent_name": "MiMo-V2-Flash", "weighted_score": 8.35, "brief_justification": "Accurately identifies the cache race, uncaught request/parsing failures, and leaked ClientSession, with clear explanations and practical fixes. Minor weakness: it frames the unhandled exception mostly around fetch_data and implies certain HTTP errors require response.json(), without discussing gather behavior or response.raise_for_status() as directly as it could." }, { "judge_key": "claude_opus_46", "judge_name": "Claude Opus 4.6", "respondent_key": "gpt_5_4", "respondent_name": "GPT-5.4", "weighted_score": 9.2, "brief_justification": "All three bugs are correctly identified with accurate explanations. The race condition analysis is solid—correctly identifying the check-then-act pattern in concurrent coroutines. The unhandled exception identification covers multiple failure points (network errors, JSON parsing, HTTP status codes, gather behavior). The resource leak is correctly identified as the unclosed ClientSession. The response is exceptionally well-structured with clear headings, code snippets, examples, and summaries. Mi" }, { "judge_key": "claude_opus_46", "judge_name": "Claude Opus 4.6", "respondent_key": "gemini_31_pro", "respondent_name": "Gemini 3.1 Pro", "weighted_score": 8.2, "brief_justification": "All three bugs are correctly identified: the race condition in fetch_parallel's concurrent cache access, the unhandled exception from network/JSON errors with no try/except, and the resource leak from never closing the ClientSession. The explanations are detailed and accurate, with good discussion of why each is problematic and how to fix them. The response is well-structured and clear. Minor deduction: the resource leak explanation appears truncated, and the race condition explanation could hav" }, { "judge_key": "claude_opus_46", "judge_name": "Claude Opus 4.6", "respondent_key": "claude_sonnet_46", "respondent_name": "Claude Sonnet 4.6", "weighted_score": 9.55, "brief_justification": "All three bugs are correctly identified with precise explanations of why each is problematic. The race condition analysis correctly identifies coroutine interleaving at await points. The unhandled exception analysis correctly identifies that aiohttp doesn't raise on 4xx/5xx and that .json() can fail on non-JSON responses. The resource leak correctly identifies both the missing close() and the event loop context issue. Each fix is well-crafted and production-quality. The summary table and code ex" }, { "judge_key": "claude_opus_46", "judge_name": "Claude Opus 4.6", "respondent_key": "grok_420", "respondent_name": "Grok 4.20", "weighted_score": 8.95, "brief_justification": "All three bugs are correctly identified with accurate explanations. The race condition analysis is solid—explaining the check-then-act pattern with await points creating interleaving opportunities. The resource leak is correctly identified. The unhandled exception bug is reasonable, though it's arguably more of a missing error handling pattern than a traditional 'bug'—but given the prompt's framing, it's the most defensible answer. The explanation of asyncio.gather's default behavior propagating" }, { "judge_key": "claude_opus_46", "judge_name": "Claude Opus 4.6", "respondent_key": "deepseek_v4", "respondent_name": "DeepSeek V4", "weighted_score": 8.1, "brief_justification": "The response correctly identifies the race condition in fetch_parallel/fetch_single, the resource leak with the unclosed ClientSession, and the unhandled exception from network calls. The race condition and resource leak identifications are spot-on. The unhandled exception bug is reasonable but somewhat generic - it's more of a missing error handling pattern than a specific bug, though it's a valid interpretation given the question's framing. The fix provided is good but the synchronized_cache d" }, { "judge_key": "claude_opus_46", "judge_name": "Claude Opus 4.6", "respondent_key": "gpt_oss_120b", "respondent_name": "GPT-OSS-120B", "weighted_score": 0.7, "brief_justification": "The response is completely empty - no analysis, no bug identification, no explanation provided whatsoever." }, { "judge_key": "claude_opus_46", "judge_name": "Claude Opus 4.6", "respondent_key": "gemini_3_flash", "respondent_name": "Gemini 3 Flash Preview", "weighted_score": 9.2, "brief_justification": "All three bugs are correctly identified with accurate explanations. The race condition in fetch_single with concurrent cache access is well explained including the cache stampede concept. The unhandled exception analysis of asyncio.gather's default behavior is correct. The resource leak of the unclosed ClientSession is properly identified. The response also provides clear fixes for each issue. Minor nitpick: the race condition explanation could have been slightly more precise about the specific " }, { "judge_key": "claude_opus_46", "judge_name": "Claude Opus 4.6", "respondent_key": "minimax_m25", "respondent_name": "MiniMax M2.5", "weighted_score": 7.55, "brief_justification": "The response correctly identifies the resource leak (ClientSession never closed) and the race condition (concurrent cache access in fetch_parallel). Both explanations are thorough with good fixes. However, the response only covers 2 of the 3 required bugs - it appears to be cut off and never identifies the unhandled exception bug (response.json() can raise exceptions like ContentTypeError, ClientError, etc., which are not caught with try/except, potentially crashing the entire gather and leaving" }, { "judge_key": "claude_opus_46", "judge_name": "Claude Opus 4.6", "respondent_key": "mimo_v2_flash", "respondent_name": "MiMo-V2-Flash", "weighted_score": 9.2, "brief_justification": "All three bugs are correctly identified: the race condition in concurrent cache access via fetch_parallel/fetch_single, the unhandled exception in network requests, and the resource leak from never closing the aiohttp.ClientSession. Each explanation is thorough, clearly articulated, and includes practical fix examples. Minor note: the lock creation itself in the fix has a subtle race condition (creating locks per URL without synchronization), but this is a minor nitpick on the fix rather than th" }, { "judge_key": "gemini_31_pro", "judge_name": "Gemini 3.1 Pro", "respondent_key": "gpt_5_4", "respondent_name": "GPT-5.4", "weighted_score": 9.65, "brief_justification": "The response accurately identifies all three bugs, explains the root causes clearly, and details why they are problematic. The structure is excellent and the analysis is insightful." }, { "judge_key": "gemini_31_pro", "judge_name": "Gemini 3.1 Pro", "respondent_key": "claude_opus_46", "respondent_name": "Claude Opus 4.6", "weighted_score": 10, "brief_justification": "The response perfectly identifies all three bugs, explains the underlying mechanics of why they occur in asyncio/aiohttp, and provides robust, production-ready fixes. The formatting is excellent and highly readable." }, { "judge_key": "gemini_31_pro", "judge_name": "Gemini 3.1 Pro", "respondent_key": "claude_sonnet_46", "respondent_name": "Claude Sonnet 4.6", "weighted_score": 10, "brief_justification": "" }, { "judge_key": "gemini_31_pro", "judge_name": "Gemini 3.1 Pro", "respondent_key": "grok_420", "respondent_name": "Grok 4.20", "weighted_score": 10, "brief_justification": "The response accurately identifies all three bugs, provides excellent explanations of why they are problematic, and offers practical, actionable fixes. The analysis is deep, mentioning specific consequences like the thundering herd problem and gather's fail-fast behavior." }, { "judge_key": "gemini_31_pro", "judge_name": "Gemini 3.1 Pro", "respondent_key": "deepseek_v4", "respondent_name": "DeepSeek V4", "weighted_score": 8, "brief_justification": "Accurately identified and explained all three bugs. However, the provided solution introduces a global lock that completely serializes the async network requests, defeating the purpose of asyncio." }, { "judge_key": "gemini_31_pro", "judge_name": "Gemini 3.1 Pro", "respondent_key": "gemini_3_flash", "respondent_name": "Gemini 3 Flash Preview", "weighted_score": 10, "brief_justification": "The response accurately identifies all three bugs, explains why they are problematic with excellent depth, and provides clear, actionable solutions." }, { "judge_key": "gemini_31_pro", "judge_name": "Gemini 3.1 Pro", "respondent_key": "minimax_m25", "respondent_name": "MiniMax M2.5", "weighted_score": 6.25, "brief_justification": "The response accurately identifies and deeply explains the resource leak and race condition, providing excellent fixes. However, it cuts off mid-sentence and completely fails to address the third bug (unhandled exception), resulting in low completeness." }, { "judge_key": "gemini_31_pro", "judge_name": "Gemini 3.1 Pro", "respondent_key": "mimo_v2_flash", "respondent_name": "MiMo-V2-Flash", "weighted_score": 8.5, "brief_justification": "" }, { "judge_key": "claude_sonnet_46", "judge_name": "Claude Sonnet 4.6", "respondent_key": "gpt_5_4", "respondent_name": "GPT-5.4", "weighted_score": 9, "brief_justification": "All three bugs are correctly identified with accurate explanations. The race condition analysis is spot-on regarding check-then-act in async context. The unhandled exception section correctly identifies multiple failure points including gather behavior. The resource leak explanation is accurate and includes practical symptoms. The response is well-structured, clear, and actionable. Minor deduction: the race condition could mention asyncio.Lock as a fix, and the gather issue could note that retur" }, { "judge_key": "claude_sonnet_46", "judge_name": "Claude Sonnet 4.6", "respondent_key": "claude_opus_46", "respondent_name": "Claude Opus 4.6", "weighted_score": 9.35, "brief_justification": "Excellent response that correctly identifies all three bugs with accurate technical explanations. The race condition analysis is nuanced and correct about async suspension points. The unhandled exception section correctly identifies both ContentTypeError and the gather propagation issue. The resource leak fix is practical and idiomatic. Minor quibble: the race condition fix itself has a subtle issue (creating locks without a lock on the locks dict), but this doesn't significantly detract. The su" }, { "judge_key": "claude_sonnet_46", "judge_name": "Claude Sonnet 4.6", "respondent_key": "gemini_31_pro", "respondent_name": "Gemini 3.1 Pro", "weighted_score": 8.2, "brief_justification": "The response correctly identifies all three bugs with accurate explanations. The race condition explanation is solid, correctly describing the cache stampede scenario. The unhandled exception analysis is thorough, noting the gather behavior without return_exceptions=True. The resource leak identification is correct. The response appears to be cut off mid-sentence on the resource leak explanation, which slightly reduces completeness and clarity scores. Fix suggestions are practical and actionable" }, { "judge_key": "claude_sonnet_46", "judge_name": "Claude Sonnet 4.6", "respondent_key": "grok_420", "respondent_name": "Grok 4.20", "weighted_score": 9, "brief_justification": "Accurately identifies all three bugs with clear explanations of why each is problematic. The race condition explanation is particularly good, explaining the thundering herd problem. The unhandled exception section correctly notes gather's default behavior. Minor quibble: the resource leak could also mention that creating ClientSession outside an async context is itself problematic in newer aiohttp versions. Fixes provided are practical and actionable." }, { "judge_key": "claude_sonnet_46", "judge_name": "Claude Sonnet 4.6", "respondent_key": "deepseek_v4", "respondent_name": "DeepSeek V4", "weighted_score": 8, "brief_justification": "The response correctly identifies all three bugs with clear explanations. The race condition explanation is accurate but slightly incomplete - it doesn't mention that Python's asyncio is cooperative and the race only occurs at await points, which would deepen the analysis. The resource leak identification is spot-on. The unhandled exception identification is valid though somewhat generic. The fixed code is helpful and demonstrates good async patterns like context managers and per-instance locks," }, { "judge_key": "claude_sonnet_46", "judge_name": "Claude Sonnet 4.6", "respondent_key": "gemini_3_flash", "respondent_name": "Gemini 3 Flash Preview", "weighted_score": 8.8, "brief_justification": "All three bugs are correctly identified with accurate explanations. The race condition analysis is particularly strong, correctly identifying the cache stampede pattern and why concurrent awaits cause the issue. The unhandled exception explanation is accurate about gather's default behavior. The resource leak identification is correct. The fixes suggested are appropriate and actionable. Minor deduction: the race condition explanation could more precisely note that Python's GIL doesn't protect as" }, { "judge_key": "claude_sonnet_46", "judge_name": "Claude Sonnet 4.6", "respondent_key": "minimax_m25", "respondent_name": "MiniMax M2.5", "weighted_score": 8.25, "brief_justification": "The response correctly identifies the resource leak and race condition with accurate explanations and good fix examples. However, the response appears to be cut off before identifying the third bug (unhandled exception - likely the missing error handling for failed HTTP responses or JSON parsing errors). Only 2 of the 3 requested bugs are covered, which significantly impacts completeness. The two bugs that are covered are explained with good depth and clarity." }, { "judge_key": "claude_sonnet_46", "judge_name": "Claude Sonnet 4.6", "respondent_key": "mimo_v2_flash", "respondent_name": "MiMo-V2-Flash", "weighted_score": 8.8, "brief_justification": "The response correctly identifies all three bugs: race condition in cache check-then-act pattern, unhandled exceptions in fetch_data, and resource leak from unclosed ClientSession. Each bug is well-explained with clear reasoning about why it's problematic. The fixes are practical and correct, including the important double-check pattern inside the lock for the race condition. Minor note: the race condition in _locks creation itself (if url not in self._locks) could also be a race condition, but " }, { "judge_key": "grok_420", "judge_name": "Grok 4.20", "respondent_key": "gpt_5_4", "respondent_name": "GPT-5.4", "weighted_score": 8.6, "brief_justification": "Accurately identifies the three bugs with clear explanations, examples, and why they matter. Minor incompleteness: race condition also exists in fetch_data, and resource leak could mention __aenter__/__aexit__ or context manager usage." }, { "judge_key": "grok_420", "judge_name": "Grok 4.20", "respondent_key": "claude_opus_46", "respondent_name": "Claude Opus 4.6", "weighted_score": 8.35, "brief_justification": "The response correctly identifies the three main issues with good explanations and fixes. It accurately describes the race condition in cache access, exception handling gaps, and session closure. Minor nit: the race condition description slightly overstates impact for distinct URLs, but overall analysis is solid and actionable." }, { "judge_key": "grok_420", "judge_name": "Grok 4.20", "respondent_key": "gemini_31_pro", "respondent_name": "Gemini 3.1 Pro", "weighted_score": 8.6, "brief_justification": "Accurately identifies the three bugs with clear explanations, good depth on why they matter, and practical fixes. Minor incompleteness as the resource leak explanation is cut off mid-sentence." }, { "judge_key": "grok_420", "judge_name": "Grok 4.20", "respondent_key": "claude_sonnet_46", "respondent_name": "Claude Sonnet 4.6", "weighted_score": 7.95, "brief_justification": "The response correctly identifies three distinct bugs with good explanations and fixes. However, the race condition description is slightly imprecise (asyncio uses cooperative multitasking, not threads), and the resource leak focuses on init-time creation while overlooking that fetch_data also uses the session without proper cleanup in the original code." }, { "judge_key": "grok_420", "judge_name": "Grok 4.20", "respondent_key": "deepseek_v4", "respondent_name": "DeepSeek V4", "weighted_score": 8.6, "brief_justification": "Accurately identifies the three bugs with clear explanations of why they are problematic and their locations. Provides a solid improved code example addressing the issues. Minor deduction for not noting that fetch_data also contains the race condition and for using a class-level lock that would serialize all requests." }, { "judge_key": "grok_420", "judge_name": "Grok 4.20", "respondent_key": "gpt_oss_120b", "respondent_name": "GPT-OSS-120B", "weighted_score": 4.2, "brief_justification": "The response is missing entirely; no bugs are identified or explained." }, { "judge_key": "grok_420", "judge_name": "Grok 4.20", "respondent_key": "gemini_3_flash", "respondent_name": "Gemini 3 Flash Preview", "weighted_score": 9, "brief_justification": "Accurately identifies the three main bugs with clear explanations, good structure, and practical fixes. Minor note that race condition also exists in fetch_data but is correctly highlighted in fetch_single as primary issue." }, { "judge_key": "grok_420", "judge_name": "Grok 4.20", "respondent_key": "minimax_m25", "respondent_name": "MiniMax M2.5", "weighted_score": 8.6, "brief_justification": "The response correctly identifies the resource leak and race condition with accurate explanations and good fixes. It misses the unhandled exception bug (no error handling around await response.json() or network failures), making completeness slightly lower. Overall clear, insightful, and useful." }, { "judge_key": "grok_420", "judge_name": "Grok 4.20", "respondent_key": "mimo_v2_flash", "respondent_name": "MiMo-V2-Flash", "weighted_score": 6.75, "brief_justification": "The response identifies three issues but misidentifies the unhandled exception bug (claims it's only in fetch_data, but the real one is in fetch_parallel's gather with no exception handling). It also overlooks the missing close in __init__ context. Explanations are clear and fixes are useful, but accuracy is only partial." }, { "judge_key": "deepseek_v4", "judge_name": "DeepSeek V4", "respondent_key": "gpt_5_4", "respondent_name": "GPT-5.4", "weighted_score": 9.45, "brief_justification": "Thoroughly identifies and explains all three bugs with clear reasoning and practical implications." }, { "judge_key": "deepseek_v4", "judge_name": "DeepSeek V4", "respondent_key": "claude_opus_46", "respondent_name": "Claude Opus 4.6", "weighted_score": 8.8, "brief_justification": "Detailed and accurate analysis of each bug with clear fixes provided." }, { "judge_key": "deepseek_v4", "judge_name": "DeepSeek V4", "respondent_key": "gemini_31_pro", "respondent_name": "Gemini 3.1 Pro", "weighted_score": 9.45, "brief_justification": "Accurate identification and explanation of all bugs with clear fixes." }, { "judge_key": "deepseek_v4", "judge_name": "DeepSeek V4", "respondent_key": "claude_sonnet_46", "respondent_name": "Claude Sonnet 4.6", "weighted_score": 10, "brief_justification": "Comprehensive, accurate, and detailed analysis of all bugs with clear fixes provided." }, { "judge_key": "deepseek_v4", "judge_name": "DeepSeek V4", "respondent_key": "grok_420", "respondent_name": "Grok 4.20", "weighted_score": 9.6, "brief_justification": "Accurate identification and explanation of all three bugs with clear fixes and thorough reasoning." }, { "judge_key": "deepseek_v4", "judge_name": "DeepSeek V4", "respondent_key": "gpt_oss_120b", "respondent_name": "GPT-OSS-120B", "weighted_score": 7.6, "brief_justification": "Identifies bugs accurately but lacks detailed explanations for each problem." }, { "judge_key": "deepseek_v4", "judge_name": "DeepSeek V4", "respondent_key": "gemini_3_flash", "respondent_name": "Gemini 3 Flash Preview", "weighted_score": 9.6, "brief_justification": "Accurate, thorough, and actionable with clear explanations." }, { "judge_key": "deepseek_v4", "judge_name": "DeepSeek V4", "respondent_key": "minimax_m25", "respondent_name": "MiniMax M2.5", "weighted_score": 9.6, "brief_justification": "Accurate, thorough, and actionable with clear explanations." }, { "judge_key": "deepseek_v4", "judge_name": "DeepSeek V4", "respondent_key": "mimo_v2_flash", "respondent_name": "MiMo-V2-Flash", "weighted_score": 10, "brief_justification": "Comprehensive, accurate, and actionable fixes with clear explanations." }, { "judge_key": "gpt_oss_120b", "judge_name": "GPT-OSS-120B", "respondent_key": "gpt_5_4", "respondent_name": "GPT-5.4", "weighted_score": 8.45, "brief_justification": "Accurately identifies all three bugs and explains why each is problematic; covers key points clearly and with useful detail, though could mention race condition in fetch_data and provide concrete fix examples." }, { "judge_key": "gpt_oss_120b", "judge_name": "GPT-OSS-120B", "respondent_key": "claude_opus_46", "respondent_name": "Claude Opus 4.6", "weighted_score": 9.25, "brief_justification": "Accurately identifies all three bugs, explains their impact, and offers concrete, practical fixes with clear code examples." }, { "judge_key": "gpt_oss_120b", "judge_name": "GPT-OSS-120B", "respondent_key": "gemini_31_pro", "respondent_name": "Gemini 3.1 Pro", "weighted_score": 8.05, "brief_justification": "Accurately identifies the three issues and explains why they matter, offering concrete fixes. Slightly incomplete ending reduces clarity, but overall response is thorough and actionable." }, { "judge_key": "gpt_oss_120b", "judge_name": "GPT-OSS-120B", "respondent_key": "claude_sonnet_46", "respondent_name": "Claude Sonnet 4.6", "weighted_score": 8.8, "brief_justification": "Accurately identifies all three issues, explains why they matter, and offers concrete, practical fixes with clear structure." }, { "judge_key": "gpt_oss_120b", "judge_name": "GPT-OSS-120B", "respondent_key": "grok_420", "respondent_name": "Grok 4.20", "weighted_score": 9.25, "brief_justification": "Accurately identifies all three issues, explains their impact, and offers concrete mitigation strategies; well organized and actionable." }, { "judge_key": "gpt_oss_120b", "judge_name": "GPT-OSS-120B", "respondent_key": "deepseek_v4", "respondent_name": "DeepSeek V4", "weighted_score": 8.8, "brief_justification": "Accurately identifies all three bugs, explains why each is an issue, and offers practical refactoring suggestions." }, { "judge_key": "gpt_oss_120b", "judge_name": "GPT-OSS-120B", "respondent_key": "gemini_3_flash", "respondent_name": "Gemini 3 Flash Preview", "weighted_score": 8.6, "brief_justification": "Accurately identifies all three bugs with clear explanations and practical fixes, though could mention race condition in both methods for full completeness." }, { "judge_key": "gpt_oss_120b", "judge_name": "GPT-OSS-120B", "respondent_key": "minimax_m25", "respondent_name": "MiniMax M2.5", "weighted_score": 7.25, "brief_justification": "Accurately identifies and explains two bugs with good detail, but omits the unhandled exception bug, reducing completeness and overall usefulness." }, { "judge_key": "gpt_oss_120b", "judge_name": "GPT-OSS-120B", "respondent_key": "mimo_v2_flash", "respondent_name": "MiMo-V2-Flash", "weighted_score": 8.8, "brief_justification": "Accurately identifies all three issues, explains their impact, and offers concrete fixes; well organized and actionable, though could explore more advanced mitigation strategies." }, { "judge_key": "gemini_3_flash", "judge_name": "Gemini 3 Flash Preview", "respondent_key": "gpt_5_4", "respondent_name": "GPT-5.4", "weighted_score": 9.8, "brief_justification": "The response accurately identifies all three bugs (race condition, unhandled exception, and resource leak) and provides a thorough explanation of why each is problematic with specific code references." }, { "judge_key": "gemini_3_flash", "judge_name": "Gemini 3 Flash Preview", "respondent_key": "claude_opus_46", "respondent_name": "Claude Opus 4.6", "weighted_score": 10, "brief_justification": "The response perfectly identifies all three bugs (race condition, unhandled exception, and resource leak), explains the technical reasons why they are problematic in an asynchronous context, and provides high-quality code fixes for each." }, { "judge_key": "gemini_3_flash", "judge_name": "Gemini 3 Flash Preview", "respondent_key": "gemini_31_pro", "respondent_name": "Gemini 3.1 Pro", "weighted_score": 9.6, "brief_justification": "The response accurately identifies all three bugs (race condition, unhandled exception, and resource leak) with excellent technical explanations. It correctly identifies the 'cache stampede' in the parallel execution and the lack of session closure. The response is slightly cut off at the very end but the meaning is fully conveyed." }, { "judge_key": "gemini_3_flash", "judge_name": "Gemini 3 Flash Preview", "respondent_key": "claude_sonnet_46", "respondent_name": "Claude Sonnet 4.6", "weighted_score": 10, "brief_justification": "The response correctly identifies all three bugs (race condition, unhandled exception, and resource leak) with high technical accuracy. It provides clear explanations of why they are problematic and offers robust code solutions to fix them." }, { "judge_key": "gemini_3_flash", "judge_name": "Gemini 3 Flash Preview", "respondent_key": "grok_420", "respondent_name": "Grok 4.20", "weighted_score": 9.8, "brief_justification": "The response accurately identifies all three bugs (resource leak, race condition, and unhandled exceptions) and provides clear, technically sound explanations for why they are problematic and how to fix them." }, { "judge_key": "gemini_3_flash", "judge_name": "Gemini 3 Flash Preview", "respondent_key": "deepseek_v4", "respondent_name": "DeepSeek V4", "weighted_score": 9.8, "brief_justification": "The response accurately identifies all three bugs (race condition, unhandled exception, and resource leak) and provides a clear explanation for each. The provided solution correctly addresses the issues using an async context manager for the session and a lock for the cache race condition." }, { "judge_key": "gemini_3_flash", "judge_name": "Gemini 3 Flash Preview", "respondent_key": "minimax_m25", "respondent_name": "MiniMax M2.5", "weighted_score": 8.6, "brief_justification": "The response correctly identifies the resource leak and the race condition with excellent explanations and fixes. However, it fails to explicitly identify the third bug (unhandled exception) as a distinct section, though it mentions potential failures in the race condition section. The response also cuts off at the very end." }, { "judge_key": "gemini_3_flash", "judge_name": "Gemini 3 Flash Preview", "respondent_key": "mimo_v2_flash", "respondent_name": "MiMo-V2-Flash", "weighted_score": 10, "brief_justification": "The response correctly identifies all three bugs: the race condition in the cache check-then-set logic, the unhandled exception in the network request loop, and the resource leak regarding the unclosed aiohttp session. The explanations are technically sound, and the provided fixes are idiomatic and practical." }, { "judge_key": "minimax_m25", "judge_name": "MiniMax M2.5", "respondent_key": "gpt_5_4", "respondent_name": "GPT-5.4", "weighted_score": 8.8, "brief_justification": "Accurately identifies all three bugs with clear explanations. Race condition is correctly explained as check-then-act pattern. Unhandled exceptions cover network errors, JSON parsing, and gather behavior. Resource leak correctly identifies unclosed ClientSession. Well-structured with good depth including specific failure modes and resource details." }, { "judge_key": "minimax_m25", "judge_name": "MiniMax M2.5", "respondent_key": "claude_opus_46", "respondent_name": "Claude Opus 4.6", "weighted_score": 9.45, "brief_justification": "All three bugs correctly identified with accurate explanations. Race condition explained with check-then-act pattern, unhandled exception covers HTTP errors and JSON parsing, resource leak properly identified. Clear structure, good code examples, and practical fixes provided." }, { "judge_key": "minimax_m25", "judge_name": "MiniMax M2.5", "respondent_key": "gemini_31_pro", "respondent_name": "Gemini 3.1 Pro", "weighted_score": 8.45, "brief_justification": "All three bugs correctly identified with accurate explanations of why each is problematic. Well-organized with clear headings and practical fix suggestions. Minor deduction for incomplete response (appears cut off at end, missing full resource leak fix explanation)." }, { "judge_key": "minimax_m25", "judge_name": "MiniMax M2.5", "respondent_key": "claude_sonnet_46", "respondent_name": "Claude Sonnet 4.6", "weighted_score": 9, "brief_justification": "All three bugs correctly identified with accurate technical explanations. Well-structured with code examples and fixes. Explains underlying mechanisms (await points, aiohttp behavior, event loop issues) showing good depth. Actionable solutions provided." }, { "judge_key": "minimax_m25", "judge_name": "MiniMax M2.5", "respondent_key": "grok_420", "respondent_name": "Grok 4.20", "weighted_score": 9.6, "brief_justification": "All three bugs correctly identified with accurate explanations. Well-structured response with clear code examples and practical fixes. Minor deduction for not explicitly noting fetch_data() has the same race condition issue." }, { "judge_key": "minimax_m25", "judge_name": "MiniMax M2.5", "respondent_key": "deepseek_v4", "respondent_name": "DeepSeek V4", "weighted_score": 10, "brief_justification": "Excellent response that correctly identifies all three bugs (race condition, unhandled exception, resource leak) with clear explanations of why each is problematic. Provides insightful analysis including consequences like API rate limits and connection pool issues. The fix demonstrates practical solutions including async locks, context managers, and exception handling. Well-structured and highly actionable." }, { "judge_key": "minimax_m25", "judge_name": "MiniMax M2.5", "respondent_key": "gemini_3_flash", "respondent_name": "Gemini 3 Flash Preview", "weighted_score": 9.8, "brief_justification": "All three bugs correctly identified with accurate technical explanations. Race condition (cache stampede), unhandled exception in gather, and resource leak from unclosed ClientSession are all precisely explained with good depth and actionable fixes." }, { "judge_key": "minimax_m25", "judge_name": "MiniMax M2.5", "respondent_key": "mimo_v2_flash", "respondent_name": "MiMo-V2-Flash", "weighted_score": 10, "brief_justification": "Excellent response that correctly identifies all three bugs (race condition, unhandled exception, resource leak) with clear explanations of why each is problematic and provides practical, actionable code fixes for each issue." }, { "judge_key": "mimo_v2_flash", "judge_name": "MiMo-V2-Flash", "respondent_key": "gpt_5_4", "respondent_name": "GPT-5.4", "weighted_score": 9.2, "brief_justification": "Accurately identifies all three bugs with clear explanations, covers causes and impacts, and suggests fixes, though some minor details could be expanded." }, { "judge_key": "mimo_v2_flash", "judge_name": "MiMo-V2-Flash", "respondent_key": "claude_opus_46", "respondent_name": "Claude Opus 4.6", "weighted_score": 10, "brief_justification": "Response correctly identifies all three bugs (race condition, unhandled exception, resource leak) with precise explanations and valid code fixes. It demonstrates deep understanding of async concurrency pitfalls, aiohttp specifics, and resource management patterns." }, { "judge_key": "mimo_v2_flash", "judge_name": "MiMo-V2-Flash", "respondent_key": "gemini_31_pro", "respondent_name": "Gemini 3.1 Pro", "weighted_score": 10, "brief_justification": "The response perfectly identifies all three bugs (race condition, unhandled exceptions, resource leak) with precise technical details. It explains the specific failure modes (cache stampede, ContentTypeError, socket exhaustion) and provides actionable fixes (Futures/Futures, try/except, async context manager/destructor). The analysis is thorough and accurate." }, { "judge_key": "mimo_v2_flash", "judge_name": "MiMo-V2-Flash", "respondent_key": "claude_sonnet_46", "respondent_name": "Claude Sonnet 4.6", "weighted_score": 9.55, "brief_justification": "Accurately identifies all three bugs with clear explanations, provides fixes, and covers edge cases." }, { "judge_key": "mimo_v2_flash", "judge_name": "MiMo-V2-Flash", "respondent_key": "grok_420", "respondent_name": "Grok 4.20", "weighted_score": 9.8, "brief_justification": "All three bugs are correctly identified with accurate explanations, thorough coverage, clear structure, and practical fixes." }, { "judge_key": "mimo_v2_flash", "judge_name": "MiMo-V2-Flash", "respondent_key": "deepseek_v4", "respondent_name": "DeepSeek V4", "weighted_score": 9, "brief_justification": "The response correctly identifies all three bugs (race condition, unhandled exception, resource leak) with accurate explanations. It provides a solid fix with context managers and proper error handling, though the race condition fix could be more granular." }, { "judge_key": "mimo_v2_flash", "judge_name": "MiMo-V2-Flash", "respondent_key": "gpt_oss_120b", "respondent_name": "GPT-OSS-120B", "weighted_score": 8.8, "brief_justification": "Correctly identified all three bugs with accurate explanations. The race condition in cache access, the unhandled exception in fetch_data, and the resource leak from unclosed session are all well-explained. The response could be slightly more thorough by mentioning that the race condition also exists in fetch_parallel due to concurrent cache access, but the core analysis is solid." }, { "judge_key": "mimo_v2_flash", "judge_name": "MiMo-V2-Flash", "respondent_key": "gemini_3_flash", "respondent_name": "Gemini 3 Flash Preview", "weighted_score": 9.8, "brief_justification": "The response accurately identifies all three specific bugs (race condition, exception handling, resource leak) with precise locations and clear explanations of the consequences. It provides actionable solutions for each issue." }, { "judge_key": "mimo_v2_flash", "judge_name": "MiMo-V2-Flash", "respondent_key": "minimax_m25", "respondent_name": "MiniMax M2.5", "weighted_score": 8.6, "brief_justification": "Accurately identifies all three bugs with clear explanations and practical fixes, though the response is cut off mid-sentence." } ], "meta": { "source": "The Multivac (app.themultivac.com)", "methodology": "10x10 blind peer matrix evaluation", "criteria": "correctness, completeness, clarity, depth, usefulness", "self_judgments": "excluded from rankings", "license": "Open data — cite as: The Multivac (2026)" } }