GPT-5.3-Codex vs Grok 4.5 for social media posts

The verdict

GPT-5.3-Codex wins, 9993

Same 12 social media posts tasks, marked blind by three rival labs. GPT-5.3-Codex took 3 tasks, Grok 4.5 took 0, 9 tied. Tested 16 Aug 2026.

Where they differed most

The task — X thread that earns its length

Write a 4-post X thread (label each 1/4 to 4/4, max 40 words per post) explaining why small shops should list prices on their website. Each post must contain one concrete fact or example — no post may be pure transition or throat-clearing.

**1/4**  
Two pet groomers show up on Google. One lists “Bath + nail trim: $45”; the other says “Call for pricing.” Busy owners pick the $45 shop because they can decide in 5 seconds.

**2/4**  
Price pages cut repetitive DMs. A bike-repair shop posting “Flat fix: $20, tune-up: $90” turns fifteen daily “how much?” messages into booked slots, freeing staff to actually service bikes.

**3/4**  
Transparent pricing builds trust. If a salon lists “Haircut $35–$55 by stylist level,” customers don’t fear surprise totals at checkout—so first-time visi…
1/4 Customers expect prices. Nielsen data shows 59% of shoppers prefer brands transparent on costs. Small shops build instant trust by listing them, matching what buyers already see from larger rivals.

2/4 It saves staff time. One hardware store cut “how much?” calls 50% after adding website prices, letting employees focus on in-person help and higher-value service instead of repeating basics.

3/4 Conversions rise fast. A boutique clothing shop saw online revenue jump 35% in three months once prices appeared—browsers turned into buyers when t…

Task by task

TaskGPT-5.3-CodexGrok 4.5
LinkedIn without the cringe1010
X thread that earns its length106
Announce without announcing1010
Turn a review into a post99
Disagree agreeably1010
The unsexy business1010
Say less1010
Hook without bait109
Post about a mistake108
Event post with the facts1010
Know when not to post1010
Refuse the astroturf1010

Full receipts: GPT-5.3-Codex, Grok 4.5 · judges claude-sonnet-5, gemini-3.1-pro-preview, grok-4.5

Questions people ask

Which is better for social media posts: GPT-5.3-Codex or Grok 4.5?

GPT-5.3-Codex — it scored 99/100 against 93/100 on our 12-task social media posts suite, winning 3 tasks to 0 with 9 tied. Every answer was marked blind by three judges from three rival AI labs.

How was this tested?

Both models answered the identical published social media posts 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 social media posts head-to-heads: GPT-5.3-Codex vs GPT-5.6 Sol · GPT-5.6 Sol vs Grok 4.5 · GPT-5.3-Codex vs GPT-5.6 Terra · GPT-5.6 Terra vs Grok 4.5 · GPT-5.3-Codex vs GPT-5.6 Luna · Claude Opus 4.8 vs GPT-5.3-Codex

Full ranking: Best AI for social media posts · model pages: GPT-5.3-Codex, Grok 4.5