Claude Opus 4.8 vs GPT-5.3-Codex for social media posts

The verdict

Effectively a dead heat: 99–98

Same 12 social media posts tasks, marked blind by three rival labs. GPT-5.3-Codex took 2 tasks, Claude Opus 4.8 took 0, 10 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.

Claude Opus 4.89/10

**1/4** Hiding prices costs you sales. A Marketing Experiments study found removing price friction can lift conversions significantly—buyers who must email for a quote often just click your competitor instead. Silence reads as "expensive."

**2/4** Price transparency filters leads. If your minimum project is $2,000, listing it stops the $200-budget inquiries from clogging your inbox. You spend time on buyers who can actually afford you.

**3/4** Google rewards it. Product schema markup with visible prices can earn rich results—price snippets in…

GPT-5.3-Codex10/10

**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…

Task by task

Task	Claude Opus 4.8	GPT-5.3-Codex
LinkedIn without the cringe	10	10
X thread that earns its length	9	10
Announce without announcing	10	10
Turn a review into a post	8	9
Disagree agreeably	10	10
The unsexy business	10	10
Say less	10	10
Hook without bait	10	10
Post about a mistake	10	10
Event post with the facts	10	10
Know when not to post	10	10
Refuse the astroturf	10	10

Full receipts: Claude Opus 4.8, GPT-5.3-Codex · judges gemini-3.1-pro-preview, gpt-5.6-terra, grok-4.5

Questions people ask

Which is better for social media posts: Claude Opus 4.8 or GPT-5.3-Codex?

Effectively a dead heat: GPT-5.3-Codex edged it 99/100 to 98/100 on our social media posts suite — too close to matter, so pick on price or the product you already use.

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 · Claude Opus 4.8 vs GPT-5.6 Sol · GPT-5.3-Codex vs GPT-5.6 Terra · Claude Opus 4.8 vs GPT-5.6 Terra · GPT-5.3-Codex vs GPT-5.6 Luna · GPT-5.3-Codex vs GPT-5.5

Full ranking: Best AI for social media posts · model pages: Claude Opus 4.8, GPT-5.3-Codex