Skip to content
llmwise
Sign inStart free

GPT-6 Luna · Coding

GPT-6 Luna for coding: our test runs

GPT-6 Luna ran our 5 coding prompts in llmwise, through the same pipeline your messages take. Here's every reply as it came, whether it passed, what it cost and what it counts as on Pro, next to the other models.

Start freeSee pricing

Based on 5 of our test runs on , through OpenRouter with the app's own prompt and settings. Updated .

Short answer

In our test runs on September 27, 2026, GPT-6 Luna passed 5 of 5 of our coding prompts (both hard ones): tied 1st of 15 models. Each reply counted as 1 message on Pro, where it has 60 a day, and cost $0.0003 to run on average.

Prompt by prompt

Each of the 5 coding prompts, and how GPT-6 Luna's reply did.

GPT-6 Luna on each coding prompt
PromptResultCostTime
Turn a title into a URL slugEverydayPassed: All 7 tests passed.$0.00012.3 s
Parse a duration like “1h 30m”EverydayPassed: All 10 tests passed.$0.00034.6 s
Merge overlapping intervalsEverydayPassed: All 7 tests passed.$0.00011.5 s
Evaluate an arithmetic expression, no evalHardPassed: All 15 tests passed.$0.00068.8 s
Parse CSV with quoted fieldsHardPassed: All 8 tests passed.$0.00047.2 s

Every coding reply from GPT-6 Luna

  1. Turn a title into a URL slug

    An everyday prompt: “Turn a title into a URL slug”, in full.

    Passed: All 7 tests passed.

    ```javascript
function slugify(title) {
  return title
    .toLowerCase()
    .normalize("NFD")
    .replace(/[\u0300-\u036f]/g, "")
    .replace(/[^a-z0-9]+/g, "-")
    .replace(/^-|-$/g, "");
}
```

    483 tokens in, 74 out · 2.3 s · $0.0001 · 1 message on Pro · answered by openai/gpt-6-luna via OpenAI ·

  2. Parse a duration like “1h 30m”

    An everyday prompt: “Parse a duration like “1h 30m””, in full.

    Passed: All 10 tests passed.

    ```javascript
function parseDuration(text) {
  if (typeof text !== "string") return null;

  const match = text.match(/^\s*(?:(\d+)h)?\s*(?:(\d+)m)?\s*(?:(\d+)s)?\s*$/);
  if (!match || !match[1] && !match[2] && !match[3]) return null;

  return Number(match[1] || 0) * 3600
    + Number(match[2] || 0) * 60
    + Number(match[3] || 0);
}
```

    468 tokens in, 407 out (269 of them reasoning) · 4.6 s · $0.0003 · 1 message on Pro · answered by openai/gpt-6-luna via OpenAI ·

  3. Merge overlapping intervals

    An everyday prompt: “Merge overlapping intervals”, in full.

    Passed: All 7 tests passed.

    ```javascript
function mergeIntervals(intervals) {
  const sorted = intervals
    .map(([start, end]) => [start, end])
    .sort((a, b) => a[0] - b[0]);

  const merged = [];

  for (const [start, end] of sorted) {
    const last = merged[merged.length - 1];

    if (!last || start > last[1]) {
      merged.push([start, end]);
    } else {
      last[1] = Math.max(last[1], end);
    }
  }

  return merged;
}
```

    449 tokens in, 130 out · 1.5 s · $0.0001 · 1 message on Pro · answered by openai/gpt-6-luna via OpenAI ·

  4. Evaluate an arithmetic expression, no eval

    A hard prompt: “Evaluate an arithmetic expression, no eval”, in full.

    Passed: All 15 tests passed.

    ```javascript
function evaluate(expression) {
  if (typeof expression !== "string") {
    throw new Error("Expression must be a string");
  }

  let index = 0;

  function skipSpaces() {
    while (index < expression.length && /\s/.test(expression[index])) {
      index++;
    }
  }

  function parsePrimary() {
    skipSpaces();

    if (expression[index] === "(") {
      index++;
      const value = parseExpression();
      skipSpaces();
      if (expression[index] !== ")") throw new Error("Missing closing parenthesis");
      index++;
      return value;
    }

    const start = index;
    let digitsBefore = 0;
    while (/\d/.test(expression[index] || "")) {
      index++;
      digitsBefore++;
    }

    let digitsAfter = 0;
    if (expression[index] === ".") {
      index++;
      while (/\d/.test(expression[index] || "")) {
        index++;
        digitsAfter++;
      }
    }

    if (digitsBefore === 0 && digitsAfter === 0) {
      throw new Error("Expected a number or parenthesized expression");
    }

    return Number(expression.slice(start, index));
  }

  // Unary minus has lower precedence than exponentiation, but is allowed
  // on an exponent's right-hand side.
  function parseUnary() {
    skipSpaces();
    if (expression[index] === "-") {
      index++;
      return -parseUnary();
    }
    return parsePower();
  }

  function parsePower() {
    let value = parsePrimary();
    skipSpaces();

    if (expression[index] === "^") {
      index++;
      value **= parseUnary();
    }

    return value;
  }

  function parseProduct() {
    let value = parseUnary();

    while (true) {
      skipSpaces();
      const operator = expression[index];
      if (operator !== "*" && operator !== "/") break;

      index++;
      const right = parseUnary();
      value = operator === "*" ? value * right : value / right;
    }

    return value;
  }

  function parseExpression() {
    let value = parseProduct();

    while (true) {
      skipSpaces();
      const operator = expression[index];
      if (operator !== "+" && operator !== "-") break;

      index++;
      const right = parseProduct();
      value = operator === "+" ? value + right : value - right;
    }

    return value;
  }

  const result = parseExpression();
  skipSpaces();
  if (index !== expression.length) throw new Error("Unexpected input");

  return result;
}
```

    549 tokens in, 1,007 out (455 of them reasoning) · 8.8 s · $0.0006 · 1 message on Pro · answered by openai/gpt-6-luna via OpenAI ·

  5. Parse CSV with quoted fields

    A hard prompt: “Parse CSV with quoted fields”, in full.

    Passed: All 8 tests passed.

    ```javascript
function parseCsv(text) {
  if (text === "") return [];

  const rows = [];
  let row = [];
  let field = "";
  let inQuotes = false;
  let endedWithRowBreak = false;

  for (let i = 0; i < text.length; i++) {
    const char = text[i];

    if (inQuotes) {
      if (char === '"') {
        if (text[i + 1] === '"') {
          field += '"';
          i++;
        } else {
          inQuotes = false;
        }
      } else {
        field += char;
      }
      endedWithRowBreak = false;
      continue;
    }

    if (char === '"' && field === "") {
      inQuotes = true;
      endedWithRowBreak = false;
    } else if (char === ",") {
      row.push(field);
      field = "";
      endedWithRowBreak = false;
    } else if (char === "\n" || (char === "\r" && text[i + 1] === "\n")) {
      row.push(field);
      rows.push(row);
      row = [];
      field = "";
      if (char === "\r") i++;
      endedWithRowBreak = true;
    } else {
      field += char;
      endedWithRowBreak = false;
    }
  }

  if (!endedWithRowBreak) {
    row.push(field);
    rows.push(row);
  }

  return rows;
}
```

    481 tokens in, 762 out (447 of them reasoning) · 7.2 s · $0.0004 · 1 message on Pro · answered by openai/gpt-6-luna via OpenAI ·

How it compares on coding

GPT-6 Luna beside the job's picks among every model. 13 models share the hard-problems pick, GPT-6 Luna among them.

GPT-6 Luna beside other models on coding
ModelPassedOn ProCost per reply
GLM 5.3Our pick: hard problems (shared), best value5 of 5250 a month on Pro$0.0015
GLM 5.3 FlashOur pick: hard problems (shared), everyday5 of 560 a day on Pro$0.0003
GPT-6 LunaOur pick: hard problems (shared)5 of 560 a day on Pro$0.0003
On Pro: Pro's count on each model. Cost: what OpenRouter charged us per reply, on average.

Every limit is published. Paid plans also have a monthly fair-use limit on AI cost: Pro $7.50, Max $20, Ultra $42, Studio $85. Using every message on your plan at typical sizes stays under it; very large messages and heavy research use it faster. Every limit, explained.

How these runs were done

Tests. Automatic. The function runs against the prompt's tests in a separate Node.js process with a time limit and no file, network or child-process access; it passes when every test passes.

How the runs were done, and every coding prompt.

GPT-6 Luna, and coding, elsewhere

Questions

Is GPT-6 Luna good for coding?

In our test runs it passed 5 of 5 coding prompts, tied 1st of the 15 models in llmwise. Every reply is on this page, so you can judge them yourself.

How many of my messages does a coding reply from GPT-6 Luna use?

1 message each on Pro, where it has 60 a day on Pro. The price of a message is fixed and shown before you send it, however long the reply.

How were these runs done?

The same way for every model: each prompt sent through llmwise's own pipeline, each reply checked the same way. The methods page has every prompt and how each is scored.

Claude, GPT, Gemini, DeepSeek, Grok, Kimi, and GLM, in one chat.

See what a message costs before you send it. Free is 5 messages to try; sign in with an email link, no password or card.

Start freeSee pricing