{"id":"dev-001-find-a-subtle-bug-off-by-one","suite":"dev","suite_version":"1.1","title":"Find a subtle bug (off-by-one)","prompt":"This function is supposed to return the last 3 items of a list, but it has a bug.\nFind the bug and explain the fix in 2 sentences, then show the corrected code.\n\ndef last_three(items):\n    return items[-4:-1]","scoring":"scored","expected_hint":"-3"}
{"id":"dev-002-read-a-real-stack-trace","suite":"dev","suite_version":"1.1","title":"Read a real stack trace","prompt":"A user reports their Node.js app crashes on startup with this error. What's the most likely\ncause and the first thing you'd check?\n\nTypeError: Cannot read properties of undefined (reading 'map')\n    at renderList (/app/src/components/List.jsx:14:23)\n    at processTicksAndRejections (node:internal/process/task_queues:95:5)","scoring":"exploratory"}
{"id":"dev-003-refactor-for-readability","suite":"dev","suite_version":"1.1","title":"Refactor for readability","prompt":"Refactor this JavaScript into cleaner, more idiomatic code without changing its behavior.\nBriefly explain what you changed and why.\n\nfunction f(a,b,c){if(a==true){if(b>c){return b}else{return c}}else{return a}}","scoring":"exploratory"}
{"id":"dev-004-write-tests-for-edge-cases","suite":"dev","suite_version":"1.1","title":"Write tests for edge cases","prompt":"Write 3 unit test cases (in plain pseudocode) for a function `divide(a, b)` that should\ncatch the trickiest bugs a beginner would miss.","scoring":"exploratory"}
{"id":"dev-005-fix-a-broken-sql-query","suite":"dev","suite_version":"1.1","title":"Fix a broken SQL query","prompt":"This query is supposed to return each customer's total spend, but it's returning wrong\ntotals for customers with multiple orders. What's wrong and what's the fix?\n\nSELECT customers.name, orders.amount\nFROM customers\nJOIN orders ON customers.id = orders.customer_id;","scoring":"scored","expected_hint":"GROUP BY"}
{"id":"dev-006-multi-step-instruction-following","suite":"dev","suite_version":"1.1","title":"Multi-step instruction following","prompt":"I need a Python function called `slugify` that: (1) lowercases the input, (2) replaces\nspaces with hyphens, (3) strips any character that isn't a-z, 0-9, or a hyphen, and\n(4) collapses multiple hyphens into one. Give me the function and one example call.","scoring":"scored","expected_hint":"def slugify"}
{"id":"dev-007-explain-a-tradeoff-architecture-judgment","suite":"dev","suite_version":"1.1","title":"Explain a tradeoff (architecture judgment)","prompt":"I'm building a side project SaaS with an indie budget. Should I use a queue-based\nbackground job system or just cron a script every few minutes for sending scheduled\nemails to ~500 users/day? Give me a direct recommendation, not a list of options.","scoring":"exploratory"}
{"id":"dev-008-spot-the-security-bug-xss","suite":"dev","suite_version":"1.1","title":"Spot the security bug (XSS)","prompt":"This Express route renders a user-supplied name into HTML. Name the vulnerability in one\nword and the safest fix in one sentence, then show a corrected one-liner.\n\napp.get('/hello', (req, res) => {\n  res.send('<h1>Hello ' + req.query.name + '</h1>');\n});","scoring":"scored","expected_hint":"xss"}
{"id":"dev-009-email-validation-with-regex","suite":"dev","suite_version":"1.1","title":"Email validation with regex","prompt":"Write a JavaScript function `isValidEmail(email)` that returns true only for a basic\nwell-formed email address using a regular expression. Keep it short; include the function.","scoring":"scored","expected_hint":"function"}
{"id":"dev-010-find-the-async-race","suite":"dev","suite_version":"1.1","title":"Find the async race","prompt":"This Node.js snippet is supposed to print 1000, but often prints less. What is the bug,\nand how do you fix it? Explain in 3 sentences or less, then show corrected code.\n\nlet count = 0;\nasync function bump() {\n  const next = count + 1;\n  await Promise.resolve();\n  count = next;\n}\nawait Promise.all(Array.from({ length: 1000 }, () => bump()));\nconsole.log(count);","scoring":"exploratory"}