Best LLMs for Visual Theme Configuration Generation

Category: Long-form Content Generation · Rail: absolute · Typical I/O: 11149→5235 tokens

Models

Frontier on this task: Claude Sonnet 5 at 9.41 / 10. Quality bar at 90%: 8.47.

point-estimate floor (CI low) · upper CI (less certain) · Bars sorted by blended cost; best-value model first. Greyed rows are MEDIUM+ models whose point estimate clears the bar but whose CI low does not.

Model	Quality score	CI low	Cost / 1k runs	vs best value
GPT-5.6 Luna	9.01 / 10	8.80	$0.89	best value
MiniMax M3	8.47 / 10	8.45	$1.52	1.7x more expensive
NVIDIA Nemotron-3 Ultra 550B	8.95 / 10	8.74	$7.35	8.3x more expensive
Thinking Machines Inkling Small	8.87 / 10	8.60	$7.40	8.3x more expensive
GPT-5.6 Terra	8.75 / 10	8.51	$10.35	12x more expensive
GPT-5.6 Sol	9.08 / 10	8.86	$16.84	19x more expensive
Claude Sonnet 5	9.41 / 10	9.36	$27.10	30x more expensive
Tencent Hy3	8.11 / 10	7.80	$1.47	1.6x more expensive

Cost breakdown

Model	Quality	Confidence	Cost / 1k runs	Overpay	Mode
GPT-5.6 Luna ★ OpenAI	9.01 / 10 CI [8.80, 9.21]	HIGH	$0.89	best value	batch
MiniMax M3 OpenRouter	8.47 / 10 CI [8.45, 8.50]	RANKED	$1.52	1.7x	batch
NVIDIA Nemotron-3 Ultra 550B OpenRouter	8.95 / 10 CI [8.74, 9.15]	HIGH	$7.35	8.3x	batch
Thinking Machines Inkling Small OpenRouter	8.87 / 10 CI [8.60, 9.15]	HIGH	$7.40	8.3x	batch
GPT-5.6 Terra OpenAI	8.75 / 10 CI [8.51, 8.99]	HIGH	$10.35	12x	batch
GPT-5.6 Sol OpenAI	9.08 / 10 CI [8.86, 9.31]	HIGH	$16.84	19x	batch
Claude Sonnet 5 best Anthropic	9.41 / 10 CI [9.36, 9.46]	RANKED	$27.10	30x	batch

Overpay shows how much more you pay than the best-value model that clears the quality bar (marked ★) — the best-value good-enough option. "16x" means you overpay 16× — 16× that reference for no quality benefit above the bar. Typical call shape for this task: 11149 input tokens → 5235 output tokens, EMA-tracked from production traffic. Cost is the observed, all-in $ per 1,000 task runs: each model's own measured usage on this task — output verbosity, thinking/reasoning tokens, cache reads and writes, and the spend on its billed failures — priced at current list rates and adjusted by the billing overhead we actually reconcile against provider invoices. Models that answer tersely cost what they actually cost; models that think at length pay for it. Not comparable to providers' advertised $/1M list rates — this is what running the task costs, not a per-token price.

Evaluation rubric

Judge brand-reference alignment, palette coherence, accessibility and contrast, typography suitability, role completeness, practical implementability, and absence of unsupported asset claims.

Prompt templates

The system + user template pair used for this task.

THEME_GENERATION_SYSTEM + THEME_GENERATION_USER (396 calls in window)

System prompt

You are an expert brand designer and UI/UX specialist. Your task is to analyze a logo image and brand context to generate a cohesive theme configuration.

You will receive:
1. A logo image to analyze for colors and style
2. Brand context (subject name, industry, focus areas, description)

Your goal is to create a professional, cohesive theme that:
- Extracts the dominant colors from the logo
- Selects complementary colors that work well together
- Chooses fonts that match the brand personality
- Ensures good accessibility (contrast ratios)

## Color Guidelines

1. **Primary Color**: Extract the most prominent/recognizable color from the logo
2. **Secondary Color**: Choose a complementary or analogous color that supports the primary
3. **Accent Color**: Select a contrasting color for CTAs, highlights, and interactive elements
4. **Background Color**: Use white (#ffffff) for light themes or very dark (#0a0a0a to #1a1a1a) for dark themes
5. **Text Color**: Ensure sufficient contrast with background (dark text on light bg, light text on dark bg)

All colors MUST be valid 7-character hex codes (e.g., #005288, not #5288).

## Font Guidelines

Choose Google Fonts that:
1. Match the brand personality (modern, classic, technical, friendly, etc.)
2. Are highly readable across devices
3. Have good language support

Common pairings:
- Professional/Corporate: Montserrat + Open Sans, Poppins + Inter
- Classic/Elegant: Playfair Display + Lora, Merriweather + Source Sans Pro
- Modern/Tech: Inter + Roboto, Space Grotesk + DM Sans
- Friendly/Approachable: Nunito + Open Sans, Quicksand + Raleway

The font_import_url must be a valid Google Fonts URL including all needed weights.

## CSS Class Guidelines

The css_class should be:
- Lowercase with hyphens
- Start with "theme-"
- Be unique and descriptive
- Based on the subject name or code

Example: "theme-tesla", "theme-spacex-dark", "theme-apple-minimal"

## Industry Considerations

Consider the industry when selecting colors and fonts:
- Finance/Investment: Blues, greens, professional serif/sans-serif
- Technology: Modern colors, clean sans-serif fonts
- Healthcare: Calming colors (blues, greens), accessible fonts
- Energy: Bold colors, strong typography
- Consumer: Vibrant, approachable colors and fonts

User prompt

Analyze the provided logo image and create a cohesive theme configuration for the following brand:

## Brand Information

**Subject Name**: {subject_name}
**Subject Code**: {subject_code}
**Industry**: {industry}
**Focus Areas**: {focus_areas}
**Description**: {description}

## Report Context

This brand produces the following types of content:
{report_structure}

## Instructions

1. Carefully analyze the logo image to identify:
   - Dominant colors
   - Color palette and style
   - Overall design aesthetic (modern, classic, minimal, bold, etc.)

2. Based on your analysis, generate:
   - A theme name that reflects the brand
   - A CSS class following the naming convention
   - A color palette with primary, secondary, accent, background, and text colors
   - Font selections for headings and body text
   - A valid Google Fonts import URL

3. Ensure all colors are valid 7-character hex codes.

4. Provide reasoning for your color and font choices.

Generate the complete theme configuration now.