{ "entity": "gpt-5-6-sol", "entity_type": "model", "category": "Coding", "suite": "suite-2026-08-skills/coding", "model": "openai/gpt-5.6-sol", "judges": [ "anthropic/claude-sonnet-5", "google/gemini-3.1-pro-preview", "x-ai/grok-4.5" ], "judge_protocol": "judge-2026-08", "anchors": "solo-2026-08-a", "score": 93, "caps": 0, "cost_usd": 0.6632, "started_at": "2026-08-16T06:28:35.931Z", "finished_at": "2026-08-16T06:30:05.627Z", "tasks": [ { "id": "c1", "name": "Duration parser", "prompt": "Write a Python function parse_duration(s) that converts strings like '1h30m', '45s', '2h', '90m', '1h2m3s' into total seconds. Raise ValueError on anything malformed. Include three assert-based tests, one of which covers a malformed input.", "output": "```python\nimport re\n\n_DURATION_PATTERN = re.compile(\n r\"(?:(?P[0-9]+)h)?\"\n r\"(?:(?P[0-9]+)m)?\"\n r\"(?:(?P[0-9]+)s)?\"\n)\n\n\ndef parse_duration(s):\n if not isinstance(s, str) or not s:\n raise ValueError(\"Malformed duration\")\n\n match = _DURATION_PATTERN.fullmatch(s)\n if not match:\n raise ValueError(f\"Malformed duration: {s!r}\")\n\n hours = int(match.group(\"hours\") or 0)\n minutes = int(match.group(\"minutes\") or 0)\n seconds = int(match.group(\"seconds\") or 0)\n\n return hours * 3600 + minutes * 60 + seconds\n\n\ndef raises_value_error(value):\n try:\n parse_duration(value)\n except ValueError:\n return True\n return False\n\n\nassert parse_duration(\"1h30m\") == 5400\nassert parse_duration(\"1h2m3s\") == 3723\nassert raises_value_error(\"1h30x\")\n```", "latency_ms": 12636, "cost": 0.020415, "task_score": 10, "judges": [ { "judge": "anthropic/claude-sonnet-5", "score": 8, "violates": false, "reasoning": "Correct regex-based parser, raises ValueError properly, includes three asserts (two valid, one malformed via helper). Minor style deviation using helper function instead of direct assert with try/except, but functionally meets requirements." }, { "judge": "google/gemini-3.1-pro-preview", "score": 10, "violates": false, "reasoning": "The function correctly parses the duration strings using a regex, raises ValueError on malformed inputs, and includes exactly three assert-based tests (including one for malformed input). Code is clean and accurate." }, { "judge": "x-ai/grok-4.5", "score": 10, "violates": false, "reasoning": "Correct regex parser, proper ValueError handling, three solid asserts including malformed case. Fully meets spec." } ], "machine_checks": null, "machine_violation": false, "machine_reasons": [] }, { "id": "c2", "name": "Find the bug", "prompt": "This is meant to return the average of the positive numbers but returns the wrong value. Identify the bug, explain it in one sentence, and give the corrected function.\n\nfunction avgPositive(xs) {\n let sum = 0, n = 0;\n for (const x of xs) {\n if (x > 0) sum += x;\n n++;\n }\n return sum / n;\n}", "output": "**Bug:** `n` is incremented for every element, including non-positive values.\n\n```js\nfunction avgPositive(xs) {\n let sum = 0, n = 0;\n for (const x of xs) {\n if (x > 0) {\n sum += x;\n n++;\n }\n }\n return n === 0 ? 0 : sum / n;\n}\n```", "latency_ms": 2256, "cost": 0.00312, "task_score": 9, "judges": [ { "judge": "anthropic/claude-sonnet-5", "score": 9, "violates": false, "reasoning": "Correctly identifies bug, concise explanation, fixed code correct and adds edge-case handling for empty/no-positive case." }, { "judge": "google/gemini-3.1-pro-preview", "score": 10, "violates": false, "reasoning": "The response perfectly identifies the bug, explains it in a single sentence, and provides a corrected function that even handles the division by zero edge case." }, { "judge": "x-ai/grok-4.5", "score": 9, "violates": false, "reasoning": "Correct bug ID and one-sentence explain; solid fix with zero-guard. Minor extra polish beyond minimal ask." } ], "machine_checks": null, "machine_violation": false, "machine_reasons": [] }, { "id": "c3", "name": "SQL without window functions", "prompt": "Given tables users(id, email) and orders(id, user_id, created_at, total), write SQL returning the email and order count of every user with more than 3 orders in the last 30 days, most orders first. Do not use window functions. Target Postgres.", "output": "```sql\nSELECT\n u.email,\n COUNT(o.id) AS order_count\nFROM users AS u\nJOIN orders AS o\n ON o.user_id = u.id\nWHERE o.created_at >= CURRENT_TIMESTAMP - INTERVAL '30 days'\nGROUP BY u.id, u.email\nHAVING COUNT(o.id) > 3\nORDER BY order_count DESC, u.email;\n```", "latency_ms": 5637, "cost": 0.007635, "task_score": 10, "judges": [ { "judge": "anthropic/claude-sonnet-5", "score": 9, "violates": false, "reasoning": "Correct, valid Postgres SQL, no window functions, meets filter/order/count requirements clearly and concisely." }, { "judge": "google/gemini-3.1-pro-preview", "score": 10, "violates": false, "reasoning": "The SQL query is perfectly accurate, targets Postgres correctly, avoids window functions, and fulfills all filtering, grouping, and sorting requirements." }, { "judge": "x-ai/grok-4.5", "score": 10, "violates": false, "reasoning": "Correct Postgres SQL; meets all requirements exactly with clear, efficient query." } ], "machine_checks": null, "machine_violation": false, "machine_reasons": [] }, { "id": "c4", "name": "Infinite useEffect", "prompt": "Explain precisely why this React effect loops forever, then give the fixed version.\n\nconst [items, setItems] = useState([]);\nuseEffect(() => {\n fetch('/api/items').then(r => r.json()).then(setItems);\n}, [items]);", "output": "`items` is listed as a dependency, so the effect runs whenever its value changes:\n\n1. The effect fetches data.\n2. `setItems(...)` stores the fetched array.\n3. Updating state causes a render.\n4. The fetched array is usually a new object reference, so React considers `items` changed (`Object.is` comparison).\n5. The effect runs again and repeats indefinitely.\n\nIf the data should be fetched once when the component mounts, use an empty dependency array:\n\n```jsx\nconst [items, setItems] = useState([]);\n\nuseEffect(() => {\n fetch('/api/items')\n .then(r => r.json())\n .then(setItems);\n}, []);\n```\n\nA safer version also prevents updating state after unmount:\n\n```jsx\nconst [items, setItems] = useState([]);\n\nuseEffect(() => {\n const controller = new AbortController();\n\n fetch('/api/items', { signal: controller.signal })\n .then(r => r.json())\n .then(setItems)\n .catch(error => {\n if (error.name !== 'AbortError') {\n console.error(error);\n }\n });\n\n return () => controller.abort();\n}, []);\n```\n\nIn React Strict Mode, the effect may run twice during development to detect unsafe side effects, but it will not loop indefinitely.", "latency_ms": 5139, "cost": 0.010755, "task_score": 10, "judges": [ { "judge": "anthropic/claude-sonnet-5", "score": 9, "violates": false, "reasoning": "Accurate, clear explanation with correct fix and bonus safe version. Minor verbosity but no errors; fully addresses the task." }, { "judge": "google/gemini-3.1-pro-preview", "score": 10, "violates": false, "reasoning": "The response accurately explains the infinite loop caused by the new array reference triggering the dependency array, and provides clear, correct fixes including a best-practice version with an AbortController." }, { "judge": "x-ai/grok-4.5", "score": 10, "violates": false, "reasoning": "Precise correct explanation of reference equality loop; clean fixed code with empty deps plus robust abort variant; highly useful and clear." } ], "machine_checks": null, "machine_violation": false, "machine_reasons": [] }, { "id": "c5", "name": "Typed debounce", "prompt": "Write a debounce function in TypeScript that preserves the argument types of the wrapped function, returns a function with a .cancel() method, and does not use 'any'. Explain in one sentence why the naive generic signature loses type information.", "output": "```ts\ntype Debounced = ((...args: Args) => void) & {\n cancel(): void;\n};\n\nfunction debounce(\n fn: (...args: Args) => unknown,\n delayMs: number,\n): Debounced {\n let timer: ReturnType | undefined;\n\n return Object.assign(\n (...args: Args): void => {\n if (timer !== undefined) clearTimeout(timer);\n\n timer = setTimeout(() => {\n timer = undefined;\n fn(...args);\n }, delayMs);\n },\n {\n cancel(): void {\n if (timer !== undefined) {\n clearTimeout(timer);\n timer = undefined;\n }\n },\n },\n );\n}\n```\n\nA naive signature such as `(...args: unknown[])` loses type information because it erases the wrapped function’s specific parameter tuple instead of capturing and reusing it.", "latency_ms": 13786, "cost": 0.021745, "task_score": 9, "judges": [ { "judge": "anthropic/claude-sonnet-5", "score": 8, "violates": false, "reasoning": "Correct, no 'any', has cancel(), preserves types, explanation given. Minor: explanation could better address a plausible naive generic (e.g., (fn:T)=>T) but still accurate and concise." }, { "judge": "google/gemini-3.1-pro-preview", "score": 10, "violates": false, "reasoning": "The response perfectly implements the debounce function with strict typing, avoiding 'any', and includes the required cancel method. The one-sentence explanation is accurate and concise." }, { "judge": "x-ai/grok-4.5", "score": 9, "violates": false, "reasoning": "Correct typed debounce with cancel; no any; one-sentence explanation accurate. Minor: return type voids original fn return." } ], "machine_checks": null, "machine_violation": false, "machine_reasons": [] }, { "id": "c6", "name": "Leftmost binary search", "prompt": "Implement binary search that returns the index of the FIRST occurrence of a target in a sorted array with duplicates, or -1. Give the code and state the complexity. Include the test case that distinguishes it from an ordinary binary search.", "output": "```python\ndef first_occurrence(nums, target):\n left, right = 0, len(nums) - 1\n result = -1\n\n while left <= right:\n mid = left + (right - left) // 2\n\n if nums[mid] == target:\n result = mid\n right = mid - 1 # Continue searching to the left\n elif nums[mid] < target:\n left = mid + 1\n else:\n right = mid - 1\n\n return result\n```\n\n### Distinguishing test case\n\n```python\nnums = [1, 2, 2, 2, 3]\n\nassert first_occurrence(nums, 2) == 1\nassert first_occurrence(nums, 4) == -1\n```\n\nAn ordinary binary search may return index `2` for target `2`, while this version returns the first occurrence at index `1`.\n\n- **Time complexity:** `O(log n)`\n- **Space complexity:** `O(1)`", "latency_ms": 5251, "cost": 0.00908, "task_score": 10, "judges": [ { "judge": "anthropic/claude-sonnet-5", "score": 9, "violates": false, "reasoning": "Correct implementation, proper complexity stated, distinguishing test case included clearly. Concise and useful for the task." }, { "judge": "google/gemini-3.1-pro-preview", "score": 10, "violates": false, "reasoning": "The response perfectly fulfills all requirements: it provides correct code, states the complexity, and includes a clear test case demonstrating the difference from standard binary search." }, { "judge": "x-ai/grok-4.5", "score": 10, "violates": false, "reasoning": "Correct first-occurrence binary search, proper complexities, clear distinguishing test; fully meets all task requirements with no flaws." } ], "machine_checks": null, "machine_violation": false, "machine_reasons": [] }, { "id": "c7", "name": "Security review", "prompt": "Review this Express handler and list every security problem you find, most severe first, each with the fix.\n\napp.get('/file', (req, res) => {\n const p = req.query.name;\n db.query(`SELECT * FROM files WHERE name = '${p}'`, (e, rows) => {\n res.sendFile(__dirname + '/uploads/' + p);\n });\n});", "output": "## Security issues, most severe first\n\n1. **SQL injection**\n ```js\n db.query(`SELECT * FROM files WHERE name = '${p}'`, ...)\n ```\n `p` is inserted directly into SQL. Even though the rows are ignored, attackers may perform blind/time-based injection, extract data, or modify data if the driver permits stacked statements.\n\n **Fix:** Use parameterized queries and a least-privileged database account. Disable multiple statements unless required.\n ```js\n db.query('SELECT storage_name FROM files WHERE name = ?', [p], ...)\n ```\n\n2. **Path traversal / arbitrary file disclosure**\n ```js\n res.sendFile(__dirname + '/uploads/' + p);\n ```\n Values such as `../../config/secrets.json` can escape the upload directory and expose files readable by the process.\n\n **Fix:** Do not use a user-supplied path. Accept an opaque file ID, look up a server-generated storage name, and serve it from a fixed root. Validate the stored name as defense in depth.\n ```js\n res.sendFile(storageName, { root: uploadRoot, dotfiles: 'deny' }, callback);\n ```\n If users can create symlinks inside the upload directory, lexical root checks may not be sufficient; prohibit symlinks or verify the resolved real path remains under the upload root.\n\n3. **Broken access control**\n The handler shows no authentication or authorization, and the query does not scope files to the current user. Anyone who knows or guesses a filename may retrieve it.\n\n **Fix:** Require authentication and include ownership or ACL checks in the database query:\n ```sql\n SELECT storage_name FROM files WHERE id = ? AND owner_id = ?\n ```\n Do not rely on filenames being secret. If authentication is applied globally, still enforce per-file authorization here.\n\n4. **The database check is completely ignored**\n The file is sent regardless of:\n - whether the query failed,\n - whether a matching row exists,\n - whether the user is allowed to access the row.\n\n This defeats any intended existence or authorization check.\n\n **Fix:** Return on database error or missing/unauthorized records, and only call `sendFile` after a successful lookup.\n\n5. **Unvalidated input type and format**\n `req.query.name` is not guaranteed to be a string; depending on query parsing, it may be an array or object. There are also no length or character restrictions.\n\n **Fix:** Validate before using it. Prefer a bounded opaque ID:\n ```js\n if (typeof req.query.id !== 'string' ||\n !/^[0-9a-f-]{36}$/i.test(req.query.id)) {\n return res.status(400).end();\n }\n ```\n\n6. **Potential stored XSS / active-content execution**\n If users can upload HTML, SVG, or similar active content, `sendFile` may serve it inline under the application’s origin. Opening it could execute attacker-controlled code with same-origin privileges.\n\n **Fix:** Serve untrusted uploads from a separate cookieless origin, or force downloads with `Content-Disposition: attachment`. Also set:\n ```http\n X-Content-Type-Options: nosniff\n ```\n Restrict allowed upload types and verify content rather than trusting extensions.\n\n7. **Unsafe error handling and possible information leakage**\n Database errors are ignored, and file-serving errors are not handled explicitly. Default error handling may expose filesystem paths or stack traces in a misconfigured production environment.\n\n **Fix:** Handle both errors, log details server-side, and return generic responses. Ensure production error middleware does not expose internals.\n\n8. **Sensitive-response caching may be inappropriate**\n If these files are private, browser or intermediary caching could retain them.\n\n **Fix:** Apply an appropriate policy, such as:\n ```http\n Cache-Control: private, no-store\n ```\n depending on the file sensitivity.\n\n## Safer pattern\n\n```js\nconst path = require('path');\nconst uploadRoot = path.resolve(__dirname, 'uploads');\n\napp.get('/file', requireAuth, (req, res, next) => {\n const id = req.query.id;\n\n if (typeof id !== 'string' || !/^[0-9a-f-]{36}$/i.test(id)) {\n return res.status(400).send('Invalid file ID');\n }\n\n db.query(\n `SELECT storage_name, original_name\n FROM files\n WHERE id = ? AND owner_id = ?`,\n [id, req.user.id],\n (err, rows) => {\n if (err) return next(err);\n if (rows.length !== 1) return res.sendStatus(404);\n\n const { storage_name: storageName, original_name: originalName } = rows[0];\n\n // Defense in depth: storage names should be generated by the server.\n if (!/^[0-9a-f-]{36}$/i.test(storageName)) {\n return next(new Error('Invalid stored filename'));\n }\n\n res.set({\n 'Cache-Control': 'private, no-store',\n 'X-Content-Type-Options': 'nosniff'\n });\n res.attachment(originalName);\n\n res.sendFile(\n storageName,\n { root: uploadRoot, dotfiles: 'deny' },\n err => {\n if (err) next(err);\n }\n );\n }\n );\n});\n```\n\nIf the database lookup serves no authorization or metadata purpose, remove it entirely—but still use a safe, fixed-root file mapping rather than accepting filesystem paths from the client.", "latency_ms": 39450, "cost": 0.073865, "task_score": 10, "judges": [ { "judge": "anthropic/claude-sonnet-5", "score": 9, "violates": false, "reasoning": "Thorough, accurate, correctly prioritized, provides concrete fixes and safer code. Very useful and clear despite length; minor verbosity for a non-technical reader." }, { "judge": "google/gemini-3.1-pro-preview", "score": 10, "violates": false, "reasoning": "The response perfectly identifies all security issues in the provided code, orders them by severity, and provides clear, accurate fixes along with a comprehensive refactored example." }, { "judge": "x-ai/grok-4.5", "score": 10, "violates": false, "reasoning": "Flawless security review; all major issues correctly identified and ordered by severity with accurate fixes and a solid safer pattern." } ], "machine_checks": null, "machine_violation": false, "machine_reasons": [] }, { "id": "c8", "name": "Safe migration", "prompt": "Write the Postgres migration to add a NOT NULL column 'status' with default 'pending' to an orders table with 40 million rows, without taking a long exclusive lock. Give the steps in order and say which step is the dangerous one and why.", "output": "Assuming PostgreSQL 11+ and a constant default, PostgreSQL can add the default as a metadata-only operation; it does not rewrite all 40 million rows.\n\n### 1. Add the nullable column, its default, and a temporary constraint\n\nThe `NOT VALID` check is enforced for new rows but does not scan existing rows.\n\n```sql\nBEGIN;\n\n-- Fail quickly instead of waiting in the lock queue and blocking traffic.\nSET LOCAL lock_timeout = '2s';\n\nALTER TABLE orders\n ADD COLUMN status text DEFAULT 'pending',\n ADD CONSTRAINT orders_status_not_null_chk\n CHECK (status IS NOT NULL) NOT VALID;\n\nCOMMIT;\n```\n\nRetry this transaction during a quiet period if it hits the lock timeout. This takes an `ACCESS EXCLUSIVE` lock, but on PostgreSQL 11+ it should be held only briefly because `'pending'` is a constant default and no table rewrite is needed.\n\nExisting rows logically read as `status = 'pending'`; no physical backfill is required.\n\n### 2. Validate the temporary constraint\n\n```sql\nALTER TABLE orders\n VALIDATE CONSTRAINT orders_status_not_null_chk;\n```\n\nThis scans all 40 million rows, so it may take time and consume I/O, but it uses a `SHARE UPDATE EXCLUSIVE` lock rather than `ACCESS EXCLUSIVE`. Normal `SELECT`, `INSERT`, `UPDATE`, and `DELETE` operations can continue.\n\n### 3. Convert the column to a real `NOT NULL` column\n\n```sql\nBEGIN;\n\nSET LOCAL lock_timeout = '2s';\n\nALTER TABLE orders\n ALTER COLUMN status SET NOT NULL;\n\nCOMMIT;\n```\n\nBecause the validated check constraint proves that no nulls exist, current PostgreSQL versions can skip another table scan. The command still briefly requires an `ACCESS EXCLUSIVE` lock, so use a short `lock_timeout` and retry rather than waiting.\n\n### 4. Remove the temporary constraint\n\n```sql\nBEGIN;\n\nSET LOCAL lock_timeout = '2s';\n\nALTER TABLE orders\n DROP CONSTRAINT orders_status_not_null_chk;\n\nCOMMIT;\n```\n\nThe column now has both:\n\n- `NOT NULL`\n- `DEFAULT 'pending'`\n\n### Dangerous step\n\n**Step 3 is the dangerous operation if done without Step 2.** A direct `ALTER COLUMN status SET NOT NULL` normally has to verify all 40 million rows while holding an `ACCESS EXCLUSIVE` lock, blocking reads and writes for the duration. The validated check constraint lets PostgreSQL avoid that scan.\n\nSteps 1, 3, and 4 still briefly request `ACCESS EXCLUSIVE`; the short `lock_timeout` is important because a waiting exclusive-lock request can create a lock queue behind it.\n\nOn PostgreSQL 10 or older, adding a column with a non-null default rewrites the entire table. For those versions, add the column without a default, set the default separately, backfill in small committed batches, and then use the check/validate/`SET NOT NULL` sequence.", "latency_ms": 47722, "cost": 0.08807, "task_score": 9, "judges": [ { "judge": "anthropic/claude-sonnet-5", "score": 8, "violates": false, "reasoning": "Technically accurate, correct ordering, identifies dangerous step clearly, includes lock_timeout precautions and version caveats. Minor verbosity but appropriate for correctness. No explicit constraints violated." }, { "judge": "google/gemini-3.1-pro-preview", "score": 10, "violates": false, "reasoning": "Flawless response. Accurately details the PG 11+ metadata-only default addition and the check constraint validation trick to avoid long exclusive locks. Correctly identifies the dangerous step and explains why." }, { "judge": "x-ai/grok-4.5", "score": 9, "violates": false, "reasoning": "Accurate modern Postgres steps with locks explained; identifies danger correctly. Minor verbosity but highly useful and clear." } ], "machine_checks": null, "machine_violation": false, "machine_reasons": [] }, { "id": "c9", "name": "Fix the code not the test", "prompt": "This test fails. Fix the implementation, not the test.\n\n// impl\nexport const slugify = (s) => s.toLowerCase().replace(/ /g, '-');\n// test\nexpect(slugify(' Hello World! ')).toBe('hello-world');", "output": "```js\nexport const slugify = (s) =>\n s\n .toLowerCase()\n .trim()\n .replace(/[^a-z0-9]+/g, '-')\n .replace(/^-+|-+$/g, '');\n```\n\nThis trims surrounding whitespace, collapses whitespace/punctuation into a single hyphen, and removes leading or trailing hyphens.", "latency_ms": 8640, "cost": 0.0082, "task_score": 10, "judges": [ { "judge": "anthropic/claude-sonnet-5", "score": 9, "violates": false, "reasoning": "Correct fix handles trimming, collapsing spaces/punctuation, produces 'hello-world' as expected. Concise, clear, addresses task without touching test." }, { "judge": "google/gemini-3.1-pro-preview", "score": 10, "violates": false, "reasoning": "The implementation correctly fixes the bug, making the test pass. The explanation is clear, concise, and accurate." }, { "judge": "x-ai/grok-4.5", "score": 10, "violates": false, "reasoning": "Correct fix that passes the test; follows instructions exactly; clear, concise, and useful." } ], "machine_checks": null, "machine_violation": false, "machine_reasons": [] }, { "id": "c10", "name": "Race condition", "prompt": "Identify the race condition in this code, explain what interleaving causes it, and fix it.\n\nlet cache = null;\nasync function getConfig() {\n if (cache) return cache;\n const r = await fetch('/config');\n cache = await r.json();\n return cache;\n}", "output": "### Race condition\n\n`cache` is only assigned **after** both `await` operations. Two callers can interleave:\n\n1. Call A sees `cache === null` and starts fetching.\n2. While A is awaiting, call B also sees `cache === null` and starts another fetch.\n3. Both requests complete and assign to `cache`.\n\nThis causes duplicate requests and, if responses differ, whichever finishes last overwrites the other result.\n\n### Fix: cache the in-flight promise\n\n```js\nlet cache = null;\nlet configPromise = null;\n\nasync function getConfig() {\n if (cache !== null) return cache;\n\n if (!configPromise) {\n configPromise = (async () => {\n const r = await fetch('/config');\n if (!r.ok) throw new Error(`Failed to fetch config: ${r.status}`);\n\n const config = await r.json();\n cache = config;\n return config;\n })().finally(() => {\n configPromise = null;\n });\n }\n\n return configPromise;\n}\n```\n\nConcurrent callers now await the same promise, so only one request is made. If the request fails, `configPromise` is cleared so a later call can retry.\n\nIf `null` is a valid configuration value, use a separate `hasCache` boolean rather than treating `null` as the uncached sentinel.", "latency_ms": 10900, "cost": 0.02373, "task_score": 9, "judges": [ { "judge": "anthropic/claude-sonnet-5", "score": 9, "violates": false, "reasoning": "Accurate identification of race condition, correct interleaving explanation, solid fix using in-flight promise caching, clear and concise, notes edge case about null values." }, { "judge": "google/gemini-3.1-pro-preview", "score": 10, "violates": false, "reasoning": "Accurately identifies the race condition and interleaving. Provides a robust fix that caches the promise and handles errors properly. Clear, concise, and highly useful." }, { "judge": "x-ai/grok-4.5", "score": 9, "violates": false, "reasoning": "Accurate race ID and interleaving; solid promise-cache fix with retry. Clear, useful, minor extras only." } ], "machine_checks": null, "machine_violation": false, "machine_reasons": [] }, { "id": "c11", "name": "Retry with backoff", "prompt": "Write an async retry wrapper in TypeScript: exponential backoff with jitter, a maximum attempt count, and it must NOT retry on 4xx responses other than 429. Maximum 30 lines. State what happens on the final failure.", "output": "```ts\ntype RetryOptions = {\n maxAttempts: number;\n baseDelayMs?: number;\n maxDelayMs?: number;\n};\n\nexport async function retry(\n operation: () => Promise,\n { maxAttempts, baseDelayMs = 200, maxDelayMs = 10_000 }: RetryOptions\n): Promise {\n if (maxAttempts < 1) throw new Error(\"maxAttempts must be at least 1\");\n\n for (let attempt = 1; ; attempt++) {\n try {\n return await operation();\n } catch (error) {\n const e = error as { status?: number; response?: { status?: number } };\n const status = e.status ?? e.response?.status;\n const nonRetryable = status != null &&\n status >= 400 && status < 500 && status !== 429;\n\n if (nonRetryable || attempt >= maxAttempts) throw error;\n\n const limit = Math.min(maxDelayMs, baseDelayMs * 2 ** (attempt - 1));\n const delay = Math.random() * limit;\n await new Promise(resolve => setTimeout(resolve, delay));\n }\n }\n}\n```\n\n`maxAttempts` includes the initial call. On the final failed attempt, the wrapper rethrows that failure unchanged. Non-429 `4xx` failures are also rethrown immediately.", "latency_ms": 8019, "cost": 0.0138, "task_score": 8, "judges": [ { "judge": "anthropic/claude-sonnet-5", "score": 8, "violates": false, "reasoning": "Correct, concise, meets constraints; well under 30 lines, explains final failure behavior clearly. Minor: no explicit comment on jitter formula, but functionally sound." }, { "judge": "google/gemini-3.1-pro-preview", "score": 5, "violates": true, "reasoning": "The response provides a correct and well-written TypeScript implementation meeting all functional requirements, but it violates the maximum 30 lines constraint (the response is 33 lines long)." }, { "judge": "x-ai/grok-4.5", "score": 9, "violates": false, "reasoning": "Correct TS retry with exp backoff+jitter, max attempts, skips non-429 4xx; states final rethrow. Under 30 lines. Minor: assumes error shape." } ], "machine_checks": null, "machine_violation": false, "machine_reasons": [] }, { "id": "c12", "name": "Recursive type", "prompt": "Write a TypeScript type DeepPartial that makes every nested property optional, and explain in one sentence how it must handle arrays differently from plain objects.", "output": "```ts\ntype DeepPartial =\n T extends readonly (infer U)[]\n ? ReadonlyArray>\n : T extends object\n ? { [K in keyof T]?: DeepPartial }\n : T;\n```\n\nArrays must preserve their array structure while recursively applying `DeepPartial` to their element type, rather than making array methods and indices optional like plain-object properties.", "latency_ms": 8419, "cost": 0.017165, "task_score": 9, "judges": [ { "judge": "anthropic/claude-sonnet-5", "score": 8, "violates": false, "reasoning": "Correct DeepPartial implementation with array handling and clear one-sentence explanation; minor nit: forces ReadonlyArray instead of preserving mutability." }, { "judge": "google/gemini-3.1-pro-preview", "score": 9, "violates": false, "reasoning": "The type correctly implements DeepPartial and handles arrays. The explanation is accurate and exactly one sentence. Using ReadonlyArray for all arrays slightly alters mutable arrays, but it's a minor imperfection." }, { "judge": "x-ai/grok-4.5", "score": 10, "violates": false, "reasoning": "Correct DeepPartial handling arrays via element recursion; one clear sentence explains the difference; fully meets task." } ], "machine_checks": null, "machine_violation": false, "machine_reasons": [] }, { "id": "c13", "name": "Bash one-liner", "prompt": "Give me a single shell command that finds the ten largest files under the current directory recursively and prints them human-readable, largest first. It must handle filenames containing spaces. Explain each part briefly.", "output": "```sh\nfind . -type f -printf '%s\\t%p\\0' | sort -z -k1,1nr | head -z -n 10 | numfmt -z --field=1 --to=iec-i --suffix=B | tr '\\0' '\\n'\n```\n\n- `find . -type f`: recursively finds files under the current directory.\n- `-printf '%s\\t%p\\0'`: outputs each file’s byte size and path, NUL-terminated so spaces are safe.\n- `sort -z -k1,1nr`: sorts NUL-delimited records numerically by size, descending.\n- `head -z -n 10`: keeps the ten largest.\n- `numfmt`: converts byte counts to human-readable units such as `MiB`.\n- `tr '\\0' '\\n'`: displays one result per line.\n\nThis uses GNU `find` and GNU Coreutils.", "latency_ms": 16269, "cost": 0.03136, "task_score": 9, "judges": [ { "judge": "anthropic/claude-sonnet-5", "score": 7, "violates": false, "reasoning": "Correct, handles spaces via NUL delimiters, explains each part clearly; relies on GNU-specific flags (-printf, -z) not portable, minor caveat unmentioned." }, { "judge": "google/gemini-3.1-pro-preview", "score": 10, "violates": false, "reasoning": "The response provides a flawless, highly robust command using NUL-termination to safely handle spaces, correctly formats to human-readable sizes, and clearly explains each component." }, { "judge": "x-ai/grok-4.5", "score": 9, "violates": false, "reasoning": "Correct GNU pipeline handling spaces via NULs, human sizes, top-10 descending; brief accurate explanations. Minor portability note only." } ], "machine_checks": null, "machine_violation": false, "machine_reasons": [] }, { "id": "c14", "name": "Explain and cost", "prompt": "Explain what this does and give its time and space complexity, then rewrite it to be O(n).\n\ndef has_dup(xs):\n for i in range(len(xs)):\n for j in range(i+1, len(xs)):\n if xs[i] == xs[j]:\n return True\n return False", "output": "### What the original function does\n\n`has_dup(xs)` checks whether the sequence `xs` contains any duplicate values. It compares every element with all elements that come after it and returns `True` as soon as a matching pair is found.\n\n- **Worst-case time:** \\(O(n^2)\\), because it may compare roughly \\(n(n-1)/2\\) pairs.\n- **Best-case time:** \\(O(1)\\), if the first two elements are equal.\n- **Extra space:** \\(O(1)\\).\n\n### \\(O(n)\\) rewrite\n\n```python\ndef has_dup(xs):\n seen = set()\n\n for x in xs:\n if x in seen:\n return True\n seen.add(x)\n\n return False\n```\n\nEach element is checked and inserted into a set once.\n\n- **Average time:** \\(O(n)\\)\n- **Extra space:** \\(O(n)\\)\n\nThis version requires the elements of `xs` to be hashable, such as numbers, strings, or tuples of hashable values. Set operations are \\(O(1)\\) on average.", "latency_ms": 4790, "cost": 0.009725, "task_score": 9, "judges": [ { "judge": "anthropic/claude-sonnet-5", "score": 9, "violates": false, "reasoning": "Accurate explanation, correct complexities, correct O(n) rewrite using set, clear and concise. Minor nitpick: average vs worst-case not fully distinguished but acceptable." }, { "judge": "google/gemini-3.1-pro-preview", "score": 10, "violates": false, "reasoning": "The response accurately explains the function, correctly identifies the O(n^2) time and O(1) space complexity, and provides a flawless O(n) rewrite using a set, along with clear and concise explanations." }, { "judge": "x-ai/grok-4.5", "score": 9, "violates": false, "reasoning": "Accurate explanation and complexities; clean O(n) rewrite. Minor note on average-case hashing is precise but slightly pedantic for non-experts." } ], "machine_checks": null, "machine_violation": false, "machine_reasons": [] }, { "id": "c15", "name": "Regex with limits", "prompt": "Write a regex that validates UK postcodes, give a one-line explanation of each part, and then state two valid UK postcodes your regex would reject or two invalid ones it would accept. Do not claim it is perfect.", "output": "```regex\n/^(?:GIR ?0AA|[A-PR-UWYZ](?:[0-9][0-9A-HJKSTUW]?|[A-HK-Y][0-9][0-9ABEHMNPRVWXY]?) ?[0-9][ABD-HJLNP-UW-Z]{2})$/i\n```\n\n- `^` and `$` — require the entire input to match.\n- `GIR ?0AA` — handles the exceptional postcode `GIR 0AA`, with an optional space.\n- `[A-PR-UWYZ]` — matches an allowed first postcode-area letter.\n- `[0-9][0-9A-HJKSTUW]?` — matches districts for a one-letter area, such as `M1`, `M60`, or `W1A`.\n- `[A-HK-Y][0-9][0-9ABEHMNPRVWXY]?` — matches a second area letter and district, such as `SW1` or `EC1A`.\n- ` ?` — permits zero or one space between outward and inward codes.\n- `[0-9]` — matches the postcode-sector digit.\n- `[ABD-HJLNP-UW-Z]{2}` — matches the two delivery-point letters, excluding letters not used there.\n- `i` — makes matching case-insensitive.\n\nThis is a syntax check, not a complete Royal Mail allocation check; for example, it accepts the invalid/unassigned postcodes `AA1 1AA` and `AK1 1AA`.", "latency_ms": 39758, "cost": 0.075615, "task_score": 9, "judges": [ { "judge": "anthropic/claude-sonnet-5", "score": 8, "violates": false, "reasoning": "Solid regex with clear explanations and honest limitation disclaimer, giving invalid-accepted examples as requested, though didn't explicitly give valid-rejected examples." }, { "judge": "google/gemini-3.1-pro-preview", "score": 10, "violates": false, "reasoning": "The response perfectly follows all instructions, providing a highly accurate regex, clear one-line explanations for each part, and correctly identifying two invalid postcodes it would accept without claiming perfection." }, { "judge": "x-ai/grok-4.5", "score": 9, "violates": false, "reasoning": "Accurate regex with precise one-line part explanations; correctly notes two invalid accepts without claiming perfection. Minor polish only." } ], "machine_checks": null, "machine_violation": false, "machine_reasons": [] }, { "id": "c16", "name": "Callback to async", "prompt": "Refactor this to async/await with correct error propagation. Errors must not be swallowed.\n\ngetUser(id, (e, user) => {\n if (e) return cb(e);\n getOrders(user.id, (e2, orders) => {\n if (e2) return cb(e2);\n getTotals(orders, (e3, totals) => cb(e3, totals));\n });\n});", "output": "```js\nconst { promisify } = require('node:util');\n\nconst getUserAsync = promisify(getUser);\nconst getOrdersAsync = promisify(getOrders);\nconst getTotalsAsync = promisify(getTotals);\n\nasync function getUserTotals(id) {\n const user = await getUserAsync(id);\n const orders = await getOrdersAsync(user.id);\n return getTotalsAsync(orders);\n}\n```\n\nPromise-based usage:\n\n```js\ntry {\n const totals = await getUserTotals(id);\n // use totals\n} catch (err) {\n // handle or rethrow the error\n throw err;\n}\n```\n\nIf the existing caller still requires `cb`:\n\n```js\ngetUserTotals(id).then(\n totals => cb(null, totals),\n err => cb(err)\n);\n```\n\nAny error from `getUser`, `getOrders`, or `getTotals` rejects `getUserTotals` and is propagated unchanged.", "latency_ms": 5439, "cost": 0.012155, "task_score": 9, "judges": [ { "judge": "anthropic/claude-sonnet-5", "score": 8, "violates": false, "reasoning": "Correct async/await refactor with proper error propagation via promisify and try/catch, plus callback compatibility shim. Minor nit: getTotalsAsync should be awaited explicitly, but returning promise still works correctly." }, { "judge": "google/gemini-3.1-pro-preview", "score": 10, "violates": false, "reasoning": "The response correctly refactors the callback hell to async/await using `promisify`. Error propagation is handled perfectly, as rejected promises will bubble up. It also provides helpful context for both promise and callback usage." }, { "judge": "x-ai/grok-4.5", "score": 9, "violates": false, "reasoning": "Correct async/await refactor with promisify; errors propagate via rejection. Clear examples. Minor: assumes Node APIs and original fns in scope." } ], "machine_checks": null, "machine_violation": false, "machine_reasons": [] }, { "id": "c17", "name": "Diagnose from a trace", "prompt": "Given this Node stack trace, state the most likely root cause and the first thing you would check:\n\nTypeError: Cannot read properties of undefined (reading 'map')\n at renderRows (/app/src/table.js:42:19)\n at Table (/app/src/table.js:12:5)\n at renderWithHooks (/app/node_modules/react-dom/cjs/react-dom.development.js:16305:18)\n\nThe component works in dev and fails only on the production build's first paint.", "output": "**Most likely root cause:** `renderRows` calls `.map()` on a collection that is `undefined` during the production build’s initial render—usually because props/state/API data has not arrived yet or the production payload shape differs.\n\n**First check:** Inspect `table.js:42` to identify the value before `.map()`, then verify its initial value and production data shape. Initialize it to an empty array or guard the render:\n\n```js\nconst rows = props.rows ?? [];\nreturn rows.map(/* ... */);\n```\n\nAlso confirm the component shows a loading/error state rather than assuming the data exists on first paint.", "latency_ms": 4282, "cost": 0.00779, "task_score": 9, "judges": [ { "judge": "anthropic/claude-sonnet-5", "score": 6, "violates": false, "reasoning": "Plausible root cause and fix, but doesn't address why prod-only vs dev works (e.g., timing/hydration differences), missing key insight into production-specific failure." }, { "judge": "google/gemini-3.1-pro-preview", "score": 10, "violates": false, "reasoning": "Accurately identifies the root cause and provides a clear, actionable first step. Perfectly balances technical accuracy with conciseness, making it highly useful." }, { "judge": "x-ai/grok-4.5", "score": 9, "violates": false, "reasoning": "Accurate root cause for prod-only first-paint map error; clear first check and fix. Minor: could note hydration/SSR more explicitly." } ], "machine_checks": null, "machine_violation": false, "machine_reasons": [] }, { "id": "c18", "name": "Idempotency", "prompt": "Design an idempotent POST /payments endpoint so a client retry cannot charge twice. Describe the key, where it is stored, what happens on a concurrent duplicate, and what you return the second time. Maximum 200 words. Name the failure mode your design still has.", "output": "Require an `Idempotency-Key` header: a client-generated UUID, scoped to the authenticated customer/merchant. Reuse it only for the same logical payment.\n\nStore in a durable database table with a unique constraint on `(customer_id, key)`:\n\n- canonical request hash\n- state: `processing`, `succeeded`, or `failed`\n- processor payment ID\n- original HTTP status and response body\n\nAtomically insert `processing` before charging. A different payload using the same key returns `409 Conflict`.\n\nOn a concurrent duplicate, the unique insert loses. If the record is complete, replay the stored status/body. If it is still `processing`, wait briefly or return `202 Accepted` with a status URL; do not start another charge.\n\nSend the same idempotency key to the payment processor. After charging, durably store the result. Every later retry returns the original response, including the same payment ID, rather than charging again.\n\n**Remaining failure mode: distributed dual-write ambiguity.** If the processor does not provide reliable idempotency, a crash after it charges but before the local result is committed leaves the server unable to know whether charging occurred; retrying may double-charge. Processor-side idempotency or reconciliation by key is therefore required.", "latency_ms": 18061, "cost": 0.022475, "task_score": 9, "judges": [ { "judge": "anthropic/claude-sonnet-5", "score": 8, "violates": false, "reasoning": "Accurate, well-structured, covers key storage, concurrency handling, replay response, and names a real failure mode. Slightly over concise but within 200 words; strong technical answer." }, { "judge": "google/gemini-3.1-pro-preview", "score": 10, "violates": false, "reasoning": "The response perfectly addresses all constraints and requirements. It concisely explains the idempotency key, storage mechanism, concurrent handling, and accurately identifies the dual-write failure mode, all well under the 200-word limit." }, { "judge": "x-ai/grok-4.5", "score": 9, "violates": false, "reasoning": "Accurate design covering key, storage, concurrency, retry response, and residual failure. Under 200 words, clear and useful." } ], "machine_checks": { "max_words": 200 }, "machine_violation": false, "machine_reasons": [] } ], "recapped_at": "2026-08-16T08:16:35.351Z", "recap_note": "Machine constraint caps applied retroactively under protocol judge-2026-08b; judge verdicts unchanged, task scores capped where a deterministic check failed." }