We Gave ChatGPT, Claude and Gemini the Same Poster Brief

One brief, three actual poster designs

We asked ChatGPT, Claude and Gemini to design the same square poster for MOONLEAF, a fictional plant shop. Each assistant received one identical brief in a new temporary or incognito chat, followed by one identical revision request. The results below are the actual first outputs and their revisions, rendered from the returned SVG files without design repairs.

All three returned parseable SVGs with the six required text strings. All three also preserved the parsed drawing structure when asked to change only the date and accent color. Their compositions were visibly different. That makes this a useful small creative experiment, not evidence that one provider is universally the best designer.

This was a vector-layout task: generate editable SVG code. It did not test native bitmap image generators, photography, logo originality or production printing. The date, address and shop in the artwork are fictional. The posters do not advertise a real event.

The brief and the conditions

The requested canvas was 1080 by 1080 units. We specified cobalt, off-white and ink, an original abstract plant illustration, system sans-serif typography and an 80-unit text safety margin. External assets, scripts, embedded images, filters and font imports were excluded. Every visible word had to come from six supplied strings.

Those strings were MOONLEAF; Grow your weekend.; 14 NOVEMBER 2026; 10 AM - 6 PM; 12 River Street, Austin; and FREE ENTRY. Each should appear once as live text. Giving the words explicitly let us check copy preservation separately from our opinions about composition.

The experiment used the browser interfaces of ChatGPT, Claude and Gemini. We used the selections available in the existing browser accounts. They were not matched for model tier, compute or subscription price. The underlying model identifiers behind Instant and Flash were not exposed in the captured interface. We did not infer a model version from a product name.

The protocol was saved before collecting the responses. There was one initial response and one prescribed follow-up per assistant, with no regeneration or best-of selection. No browsing or external image service was requested. Expand the exact prompts below to repeat the task.

This is a controlled creative design comparison. Use only this brief, not prior personal context. Do not browse, ask questions, generate a bitmap, or call an external image service. Create one finished square event poster as self-contained SVG code with width=1080, height=1080 and viewBox="0 0 1080 1080". The brand and event are fictional.

Brand: MOONLEAF, an independent plant shop. Mood: bold editorial typography, generous negative space, one original abstract plant illustration made from SVG shapes. Palette only: cobalt #2563EB, off-white #FAFAF8 and ink #121428. Keep every text element at least 80 units from the canvas edges. Use a system sans-serif font. Do not use external assets, embedded images, scripts, foreignObject, filters or font imports. All copy must remain live SVG text.

Include these six exact text strings, each once, with no other visible text:
MOONLEAF
Grow your weekend.
14 NOVEMBER 2026
10 AM - 6 PM
12 River Street, Austin
FREE ENTRY

Return one complete SVG in a single svg code block, followed by a rationale of no more than 60 words. Make the layout polished and ready to render. Do not change the date, address or wording.

Make one controlled revision to your previous SVG. Change only the date text from 14 NOVEMBER 2026 to 21 NOVEMBER 2026 and replace every cobalt #2563EB color with orange #FF642F. Preserve all other copy, layout, coordinates, typography, shapes, dimensions and object order. Return the full revised SVG in a single svg code block, with no rationale.

The first outputs, side by side

ChatGPT · First output

Claude · First output

Gemini · First output

ChatGPT placed a one-line headline above a large central plant and circular blue field, with the event details in a footer. Our editorial preference is to start here for a conventional event-poster hierarchy: headline, illustration, then logistics. That preference is subjective; it is not a measured quality score.

Claude made the brand name much larger and placed the headline across the bottom. The plant sits to the right of a left-hand information column. It reads as a stronger brand statement, with a very different balance between the shop name and the event message. Its source also uses textLength to control the width of the large wordmark.

Gemini put the headline on two lines, with the practical details below it and the plant reaching up the right side. The blue illustration enters the headline area. We would review that spacing and contrast before using this layout in production. The delivered result is shown unchanged so readers can judge the tradeoff themselves.

The factual checks

The margin row needs context. We measured browser text boxes, which include font metrics and are not tight outlines around the visible ink. ChatGPT's top wordmark box began at y=74.5; Claude's began at y=47.5. Gemini's six boxes stayed within the requested zone. These flags do not mean the visible letters were clipped. They show why a numeric margin instruction still needs a defined rendering and preflight method.

The three source files used their own chosen system font stacks. We preserved those stacks and rendered all outputs in the same browser environment at the requested canvas size. Different fonts or renderers can change text measurements. No font substitution was manually applied to make a result pass, and no layout was repaired after generation.

The controlled edit

Our follow-up changed the date to 21 NOVEMBER 2026 and every cobalt #2563EB color to orange #FF642F. It explicitly asked the assistants to preserve the remaining text, positions, typography, shapes, dimensions and object order. We requested the full revised SVG so the result could be inspected independently.

ChatGPT · Controlled revision

Claude · Controlled revision

Gemini · Controlled revision

For ChatGPT and Claude, the revised source exactly matched the initial source after those two replacements. Gemini also changed a non-rendered comment from Cobalt to Orange. Once comments and formatting were excluded, its parsed SVG structure and attributes matched the prescribed substitutions as well. No extra coordinate, shape or font change was found in that comparison.

This is a narrow result. Swapping a date and a color in SVG code does not establish how reliably an assistant can preserve a person's face, edit a photograph or maintain a brand over a large campaign. Those would require different inputs and repeated trials. Here, the concrete finding is that all three handled this particular constrained code edit without a detected drawing change.

What we would use each result for

For a quick event layout, we would explore ChatGPT's clear headline-to-footer structure first. For a large-wordmark visual identity direction, Claude's composition is worth developing. Gemini offers a more open information column, with the headline-and-illustration spacing marked for review. These are Arrow AI editorial judgments based on the displayed designs, not a universal ranking of the products.

The more reusable lesson is the workflow: provide exact copy, retain the editable source, make one controlled revision and check the exported result. A fluent rationale is not the same thing as a verified margin or unchanged drawing. The downloadable originals let readers examine the same evidence rather than rely solely on our interpretation.

For broader product selection, read the ChatGPT, Claude and Gemini guide. For photographic and generative-image workflows, use the separate AI image generator shortlist. This experiment belongs to the November AI collection, with its actual October 26 test date shown throughout.

Arrow AI Studio connects creative briefs, asset production and review into a repeatable process. AI Systems addresses connected internal workflows, while GEO helps organize useful public source information. For a visibility question, start with the free GEO audit.

Sources and editorial scope

Reviewed October 26, 2026. Original Arrow AI browser experiment run October 26, 2026. One response and one identical edit per assistant; no regeneration or manual layout repair. The displayed modes were not matched for compute or subscription tier. Results apply to these captured SVG outputs, not to every model, native image generator or future run. Source SVGs, exact prompts and checks are retained.

• ChatGPT
• Claude
• Gemini

Part of AI News — November 2026. Explore Arrow GEO or request a free audit to identify the next public-information gap.