Rewrite · 4 checks · max 400 tokens · benched 2026-09-16

GLM 5.3 vs GLM 5.2 vs GLM 5.3 Flash on product update to a 280-character post

Z Ai models side by side on "Product update to a 280-character post": GLM 5.2 scores 10/10; GLM 5.3 Flash is the cheapest answer scoring 8+ at $0.02 per 1,000 runs. Outputs, checks, judge reasons, latency and cost.

The prompt every model received

User

Turn this update into a single social media post of at most 280 characters. It must mention "v2.0" and end with the hashtag #OpenSource. Output only the post.

Update: Version 2.0 of our command-line tool is out. It is three times faster on large repositories, adds a built-in diff viewer, and is now licensed under MIT so anyone can contribute.

Rubric for the judge: Punchy post under 280 characters that mentions v2.0, the speed gain, the diff viewer and MIT, ending with #OpenSource.

Side by side

Every cell is one OpenRouter call at temperature 0 with the prompt's token cap and reasoning effort "low" where the model supports it. Cost is usage × the catalogue rate in models.json. Quality is one judge call to anthropic/claude-haiku-4.5 against the prompt's rubric, cached per prompt version.

GLM 5.3

z-ai/glm-5.3

9/10

Latency: 261ms
Cost: $0.00032
Per 1,000: $0.32

93 in · 43 out · 25 words · checks 4/4

max_chars
contains
regex
contains

v2.0 of our CLI tool is here! 🚀 3x faster on large repos, new built-in diff viewer, and now MIT-licensed so anyone can contribute. #OpenSource

Judge: Post is 127 characters, mentions v2.0, speed gain, diff viewer, and MIT licensing, ends with #OpenSource hashtag as required; only minor issue is emoji use wasn't explicitly requested but doesn't violate constraints.

GLM 5.2

z-ai/glm-5.2

10/10

top judge score

Latency: 3.0s
Cost: $0.00099
Per 1,000: $0.99

93 in · 466 out (423 reasoning) · 26 words · checks 4/4

max_chars
contains
regex
contains

Our CLI tool v2.0 is live! It's 3x faster on large repos, includes a built-in diff viewer, and is now MIT-licensed so anyone can contribute. #OpenSource

Judge: Post is 168 characters, mentions v2.0, speed gain (3x faster), diff viewer, MIT licensing, ends with #OpenSource, and is punchy and well-formatted.

GLM 5.3 Flash

z-ai/glm-5.3-flash

9/10

cheapest scoring 8+

Latency: 510ms
Cost: $1.7e-5
Per 1,000: $0.02

93 in · 40 out · 24 words · checks 4/4

max_chars
contains
regex
contains

🚀 v2.0 of our CLI tool is here! 3x faster on large repos, built-in diff viewer, and now MIT licensed — contributions welcome! #OpenSource

Judge: Post is 119 characters (well under 280), mentions v2.0, speed gain, diff viewer, and MIT licensing, ends with #OpenSource, and is punchy and engaging; only minor issue is it doesn't explicitly state 'anyone can contribute' though 'contributions welcome' conveys this adequately.

Frequently asked

What does this prompt test?

Rewrite: Punchy post under 280 characters that mentions v2.0, the speed gain, the diff viewer and MIT, ending with #OpenSource. The deterministic checks are max_chars, contains, regex, contains.

Which model should I pick for this task?

If the judge's bar of 8/10 is good enough for you, GLM 5.3 Flash at $0.02 per 1,000 runs. If you need the top score, GLM 5.2 at $0.99 per 1,000 runs.

Same prompt, other families

Run it yourself

Re-run this prompt on Z Ai with your own OpenRouter key, or tweak the wording and see what changes.