GPT-5.3-Codex vs Qwen3.7 Max for code review
GPT-5.3-Codex wins, 93–88
Same 12 code review tasks, marked blind by three rival labs. GPT-5.3-Codex took 6 tasks, Qwen3.7 Max took 0, 6 tied. Tested 27 Aug 2026.
Where they differed most
Review this function and reply with ONLY valid JSON — no prose before or after, no commentary. 1 function initials(fullName) { 2 return fullName.split(' ').map(p => p[0].toUpperCase()).join(''); 3 } It is called with values taken from a free-text form field. Return an object with exactly these keys and no others: defects (an array, empty if there are none, each item an object with keys line (number), severity (one of 'high', 'medium', 'low'), issue (string), trigger (string — the input that causes it), fix (string)), and verdict (one of 'block', 'comment', 'approve').
{"defects":[{"line":2,"severity":"high","issue":"Empty tokens cause a runtime error when calling toUpperCase on undefined.","trigger":"\"John Doe\"","fix":"Normalize and filter name parts before indexing, e.g. `fullName.trim().split(/\\s+/).filter(Boolean).map(p => p[0].toUpperCase()).join('')`."},{"line":2,"severity":"high","issue":"Function crashes if fullName is not a string (e.g., null/undefined) because split is not available.","trigger":"null","fix":"Add input validation/normalization before splitting, e.g. `if (typeof fullName !== 'stri…{
"defects": [
{
"line": 2,
"severity": "high",
"issue": "TypeError when input contains consecutive, leading, or trailing spaces, or is empty. split(' ') produces empty strings, making p[0] undefined, which throws on .toUpperCase().",
"trigger": "'John Doe' or '' or ' '",
"fix": "Filter out empty strings before mapping: fullName.split(' ').filter(Boolean).map(p => p[0].toUpperCase()).join('')"
},
{
"line": 2,
"severity": "medium",
"issue": "TypeError if fullName is null or undefined…Task by task
| Task | GPT-5.3-Codex | Qwen3.7 Max |
|---|---|---|
| The pagination that skips page one | 8 | 8 |
| Nothing wrong with it | 10 | 9 |
| Three things wrong in six lines | 10 | 9 |
| Two customers, one last item | 9 | 9 |
| Rank by what breaks | 9 | 9 |
| The review, as JSON | 10 | 8 |
| Slow is not the same as wrong | 9 | 9 |
| Overdue at one in the morning | 8 | 8 |
| Write only the comment | 10 | 9 |
| The complaint that is not a defect | 9 | 9 |
| Right, and unusable | 10 | 9 |
| Refuse the rubber stamp | 10 | 9 |
Full receipts: GPT-5.3-Codex, Qwen3.7 Max · judges claude-sonnet-5, gemini-3.1-pro-preview, grok-4.5
Questions people ask
Which is better for code review: GPT-5.3-Codex or Qwen3.7 Max?
GPT-5.3-Codex — it scored 93/100 against 88/100 on our 12-task code review suite, winning 6 tasks to 0 with 6 tied. Every answer was marked blind by three judges from three rival AI labs.
How was this tested?
Both models answered the identical published code review tasks. Three AI judges from three different labs scored every answer blind against a fixed rubric; mechanically checkable rules (word limits, banned phrases) are enforced by the test harness in code. The raw outputs and judge verdicts are downloadable.
More code review head-to-heads: GPT-5.3-Codex vs GPT-5.6 Sol · GPT-5.6 Sol vs Qwen3.7 Max · GPT-5.3-Codex vs GPT-5.6 Luna · GPT-5.6 Luna vs Qwen3.7 Max · GPT-5.3-Codex vs GPT-5.6 Terra · GPT-5.6 Terra vs Qwen3.7 Max
Full ranking: Best AI for code review · model pages: GPT-5.3-Codex, Qwen3.7 Max