Poster Designer Skill

Create professional posters and visual designs using AI image generation.

Quick Start

Generate a poster:

poster create --type event --title "Summer Music Festival" --date "2026-07-15"

Capabilities

• Event Posters — Concerts, conferences, meetups, parties
• Product Showcases — E-commerce listings, feature highlights
• Announcements — Launches, openings, special offers
• Social Media — Instagram, Facebook, Twitter graphics

Usage Patterns

Interactive Mode

Simply describe what you want:

"Create a poster for my band's gig next Friday at the Blue Note"

The skill will ask clarifying questions and generate the poster.

Template Mode

Use predefined templates:

• event — General event poster with date/time/location
• concert — Music-focused with band name and setlist
• product — Product showcase with features and pricing
• announcement — News/launch announcement
• sale — Promotional sale poster

Custom Mode

Provide detailed specifications:

"Create a minimalist poster, 1080x1920 (9:16), dark blue background, neon pink text, featuring a geometric guitar illustration"

Configuration

Set your Gemini API key:

export GEMINI_API_KEY="your-api-key"

Or create .env in the skill directory by copying .env.example:

cp .env.example .env
# Edit .env and add your API key

Security Note: Never commit your .env file or share your API key. Keep it in environment variables or secure secret storage.

Get your API key from: https://makersuite.google.com/app/apikey

Output Formats

• PNG — Default high-quality raster output
• With Text Overlay — Generated image with text composited
• Raw + Composite — Both the base image and final poster

Design Principles

Typography

• Keep text readable (minimum 24pt for important info)
• Use 2-3 fonts maximum
• Ensure high contrast between text and background

Composition

• Follow the rule of thirds
• Leave breathing room (don't overcrowd)
• Use visual hierarchy (most important info largest)

Color

• Use complementary or analogous color schemes
• Ensure accessibility (WCAG AA contrast minimum)
• Consider brand colors when provided

API Integration

The skill uses Gemini image generation API with native multimodal capabilities:

• Model: gemini-3.1-flash-image-preview (configurable)
• Supports aspect ratios: 1:1, 4:3, 16:9, 9:16, 3:4
• Output sizes: 1K (~1024px), 2K (~2048px), 4K (~3840px)

See references/api-docs.md for detailed API documentation.

Templates

See references/templates.md for available templates and customization options.

Examples

Event Poster

User: "Create a poster for a tech conference on May 15th"

Skill asks:
- Event name?
- Venue?
- Speaker lineup (optional)?
- Style preference (modern/minimal/bold)?

Then generates poster with:
- Compelling headline
- Date/time/venue prominently displayed
- Speaker photos or tech-themed visuals
- QR code placeholder for tickets

Product Showcase

User: "Design a product poster for my new wireless headphones"

Skill asks:
- Product name?
- Key features?
- Price?
- Style/tone?

Then generates:
- Hero product image
- Feature callouts
- Price and CTA
- Brand-appropriate styling

Error Handling

If image generation fails:

1. Retry with exponential backoff (up to 3 attempts)
2. Provide detailed error message
3. Offer to adjust prompt and retry

Security & Safety

• All generated content follows Gemini safety guidelines
• User content is not stored persistently
• API keys are never logged or exposed
• .env.example is provided as a template - copy to .env and add your key
• Never commit .env files with real credentials
• Keep API keys in environment variables or secure secret storage