GPT-6 Astra · Coding

GPT-6 Astra for coding: our test runs

GPT-6 Astra 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 free See pricing

Based on 5 of our test runs on September 27, 2026, through OpenRouter with the app's own prompt and settings. Updated October 15, 2026.

Short answer

In our test runs on September 27, 2026, GPT-6 Astra passed 5 of 5 of our coding prompts (both hard ones): tied 1st of 20 models. Each reply counted as 1 message on Pro, where it has 31 a month, and cost $0.0223 to run on average.

Prompt by prompt

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

GPT-6 Astra on each coding prompt
Prompt	Result	Cost	Time
Turn a title into a URL slugEveryday	Passed: All 7 tests passed.	$0.0084	2.1 s
Parse a duration like “1h 30m”Everyday	Passed: All 10 tests passed.	$0.0235	8.2 s
Merge overlapping intervalsEveryday	Passed: All 7 tests passed.	$0.0108	2.6 s
Evaluate an arithmetic expression, no evalHard	Passed: All 15 tests passed.	$0.0375	12.0 s
Parse CSV with quoted fieldsHard	Passed: All 8 tests passed.	$0.0314	9.1 s

Every coding reply from GPT-6 Astra

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(/\p{M}/gu, "")
    .replace(/[^a-z0-9]+/g, "-")
    .replace(/^-+|-+$/g, "");
}
```
```
483 tokens in, 71 out · 2.1 s · $0.0084 · 1 message on Pro · answered by openai/gpt-6-astra via OpenAI · September 27, 2026

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

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

468 tokens in, 377 out (234 of them reasoning) · 8.2 s · $0.0235 · 1 message on Pro · answered by openai/gpt-6-astra via OpenAI · September 27, 2026

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]);
  sorted.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]) {
      last[1] = Math.max(last[1], end);
    } else {
      merged.push([start, end]);
    }
  }

  return merged;
}
```

449 tokens in, 127 out · 2.6 s · $0.0108 · 1 message on Pro · answered by openai/gpt-6-astra via OpenAI · September 27, 2026

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 pos = 0;

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

  function consume(character) {
    skipSpaces();
    if (expression[pos] === character) {
      pos++;
      return true;
    }
    return false;
  }

  function fail(message) {
    throw new Error(`${message} at position ${pos}`);
  }

  function parsePrimary() {
    if (consume("(")) {
      const value = parseSum();
      if (!consume(")")) fail("Expected ')'");
      return value;
    }

    skipSpaces();
    const match = /^(?:\d+(?:\.\d*)?|\.\d+)/.exec(expression.slice(pos));
    if (!match) fail("Expected a number or '('");

    pos += match[0].length;
    return Number(match[0]);
  }

  function parsePower() {
    const base = parsePrimary();
    // Parsing the exponent as unary allows 2^-1 and makes ^ right-associative.
    return consume("^") ? base ** parseUnary() : base;
  }

  function parseUnary() {
    // Power binds more tightly than unary minus.
    return consume("-") ? -parseUnary() : parsePower();
  }

  function parseProduct() {
    let value = parseUnary();
    while (true) {
      if (consume("*")) value *= parseUnary();
      else if (consume("/")) value /= parseUnary();
      else return value;
    }
  }

  function parseSum() {
    let value = parseProduct();
    while (true) {
      if (consume("+")) value += parseProduct();
      else if (consume("-")) value -= parseProduct();
      else return value;
    }
  }

  const result = parseSum();
  skipSpaces();
  if (pos !== expression.length) fail("Unexpected input");
  return result;
}
```

549 tokens in, 640 out (200 of them reasoning) · 12.0 s · $0.0375 · 1 message on Pro · answered by openai/gpt-6-astra via OpenAI · September 27, 2026

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 atFieldStart = true;

  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;
      }
      continue;
    }

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

  if (row.length > 0 || !atFieldStart) {
    row.push(field);
    rows.push(row);
  }

  return rows;
}
```

481 tokens in, 532 out (219 of them reasoning) · 9.1 s · $0.0314 · 1 message on Pro · answered by openai/gpt-6-astra via OpenAI · September 27, 2026

How it compares on coding

GPT-6 Astra beside the job's picks among every model. 18 models share the hard-problems pick, GPT-6 Astra among them.

GPT-6 Astra beside other models on coding
Model	Passed	On Pro	Cost per reply
GLM 5.3Our pick: hard problems (shared), best value	5 of 5	250 a month on Pro	$0.0015
GLM 5.3 FlashOur pick: hard problems (shared), everyday	5 of 5	60 a day on Pro	$0.0003
GPT-6 AstraOur pick: hard problems (shared)	5 of 5	31 a month on Pro	$0.0223

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: Plus $3.75, 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.

GPT-6 Astra next to each model on coding

GPT-6 Astra against each model on the same 5 coding prompts. One run each, through OpenRouter: a wait depends on the provider and the load that day, so a lead under 10% counts as close.

Against Claude Fable 5.1: GPT-6 Astra answered 1.5× later (8.2 s to 5.5 s), cost 1.9× less, and passed 5 of 5 to its 5.
Against Claude Opus 5.5: GPT-6 Astra answered 1.1× later (8.2 s to 7.2 s), cost 1.3× more, and passed 5 of 5 to its 5.
Against Claude Sonnet 5.5: GPT-6 Astra answered 4.2× later (8.2 s to 2.0 s), cost 3.6× more, and passed 5 of 5 to its 5.
Against Claude Sonnet 5: GPT-6 Astra answered 3.1× later (8.2 s to 2.7 s), cost 2.2× more, and passed 5 of 5 to its 5.
Against Claude Haiku 5.5: GPT-6 Astra answered 2.1× later (8.2 s to 3.9 s), cost 49.3× more, and passed 5 of 5 to its 5.
Against Claude Haiku 4.5: GPT-6 Astra answered 3.5× later (8.2 s to 2.3 s), cost 8.1× more, and passed 5 of 5 to its 3. Only GPT-6 Astra passed Evaluate an arithmetic expression, no eval; Parse CSV with quoted fields.
Against GPT-6.1 Sol: GPT-6 Astra answered 1.7× later (8.2 s to 4.8 s), cost 9.7× more, and passed 5 of 5 to its 5.
Against GPT-6 Sol: GPT-6 Astra answered 1.7× later (8.2 s to 4.8 s), cost 4.3× more, and passed 5 of 5 to its 5.
Against GPT-6 Luna: GPT-6 Astra answered 1.8× later (8.2 s to 4.6 s), cost 77.9× more, and passed 5 of 5 to its 5.
Against Gemini 4 Argon: GPT-6 Astra answered 2.4× later (8.2 s to 3.5 s), cost 9.2× more, and passed 5 of 5 to its 5.
Against Gemini 3.1 Pro (preview): GPT-6 Astra answered 1.3× sooner (8.2 s to 10.3 s), cost 1.1× more, and passed 5 of 5 to its 5.
Against Gemini 3.8 Flash: GPT-6 Astra answered 2.0× later (8.2 s to 4.2 s), cost 11.4× more, and passed 5 of 5 to its 5.
Against DeepSeek V4.1 Flash: GPT-6 Astra answered 3.3× later (8.2 s to 2.5 s), cost 12.2× more, and passed 5 of 5 to its 5.
Against DeepSeek V4 Pro: GPT-6 Astra answered 14.6× sooner (8.2 s to 119.6 s), cost within 10% of it, and passed 5 of 5 to its 5.
Against Grok 4.7: GPT-6 Astra answered 3.9× sooner (8.2 s to 31.6 s), cost 1.1× less, and passed 5 of 5 to its 5.
Against Kimi K3: GPT-6 Astra answered 2.0× later (8.2 s to 4.1 s), cost 3.5× more, and passed 5 of 5 to its 5.
Against GLM 5.3: GPT-6 Astra answered 7.8× later (8.2 s to 1.1 s), cost 15.2× more, and passed 5 of 5 to its 5.
Against GLM 5.3 Flash: GPT-6 Astra answered within 10% of its time (8.2 s to 8.4 s), cost 88.3× more, and passed 5 of 5 to its 5.
Against Mistral Large 4: GPT-6 Astra answered 4.5× sooner (8.2 s to 36.8 s), cost 3.1× more, and passed 5 of 5 to its 4. Only GPT-6 Astra passed Evaluate an arithmetic expression, no eval.

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 Astra, and coding, elsewhere

Questions

Is GPT-6 Astra good for coding?

In our test runs it passed 5 of 5 coding prompts, tied 1st of the 20 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 Astra use?

1 message each on Pro, where it has 31 a month 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, GLM, and Mistral, 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.