Best Practices for Writing an OpenAI Plugin Description: A Complete Guide

Write a concise shortDescription under 120 characters highlighting the core value proposition, craft a structured longDescription explaining data sources and use cases, and populate the defaultPrompt array with 2-4 ready-to-use natural language prompts to maximize discoverability in the ChatGPT Marketplace.

The openai/plugins repository serves as the canonical reference for ChatGPT plugin development, with each plugin's metadata defined in a plugin.json file (or .codex-plugin/plugin.json) under the interface section. A well-optimized OpenAI plugin description functions as both marketing copy and technical documentation, determining how users discover, understand, and integrate your tool within the ChatGPT ecosystem.

Core Elements of an OpenAI Plugin Description

Every plugin description consists of several metadata fields that control presentation in the ChatGPT Marketplace. These fields reside in the interface object within your configuration file.

Short Description Requirements

The shortDescription field serves as your plugin's tagline in marketplace listings. According to the repository standards, this field must capture the core value proposition in 1-2 sentences using no more than 120 characters.

In plugins/quartr/.codex-plugin/plugin.json, the Quartr plugin demonstrates this concisely:

"shortDescription": "Public company IR data and earnings research"

This example avoids generic terms like "tool" or "service" while immediately communicating the specific domain (investor relations) and data type (earnings research).

Long Description Structure

The longDescription field supports 300-500 words across 2-4 paragraphs. Based on the reference implementations in plugins/quartr/.codex-plugin/plugin.json and plugins/zoominfo/.codex-plugin/plugin.json, effective long descriptions follow this structure:

1. Opening hook that restates the value proposition
2. Data source explanation detailing APIs accessed and coverage scope
3. Concrete use cases with natural language examples
4. Reliability notes and coverage limitations
5. Call-to-action directing users to prompts

The Quartr implementation exemplifies this approach:

"longDescription": "Access structured first-party IR data from over 14,500+ public companies across 65 markets... Ideal for financial research, investment analysis, and building data-driven workflows..."

Optimizing Default Prompts for Discovery

The defaultPrompt array provides ready-made queries that showcase your plugin's capabilities. These prompts appear in the ChatGPT interface as suggestions users can execute immediately.

Prompt Writing Guidelines

Each prompt should:

• Remain under 200 characters for optimal display
• Use natural language without code syntax
• Demonstrate specific functionality rather than generic queries

The Quartr plugin in plugins/quartr/.codex-plugin/plugin.json includes three effective examples:

"defaultPrompt": [
  "Find the latest relevant Quartr materials for a company.",
  "Compare recurring analyst question themes from the last two earnings calls for a company.",
  "Pull recent earnings transcripts and filings for a company and summarize forward-looking statements."
]

Technical Requirements and Compliance

Beyond descriptive text, complete plugin metadata requires specific structural elements for marketplace approval.

Category and Keywords

Select the most specific category available (e.g., "Finance" rather than "Business") and populate the optional keywords array with search terms relevant to your domain. The capabilities field accepts concise strings like "search" or "export" to indicate functional areas.

Legal and Branding Assets

Every submission must include HTTPS URLs for:

• privacyPolicyURL - Link to privacy policy
• termsOfServiceURL - Link to terms of service

As demonstrated in plugins/zoominfo/.codex-plugin/plugin.json, these URLs must use the same hostname as your plugin's website to avoid trust warnings.

Visual branding requires:

• logo and logoDark: 512×512px PNG/SVG files with transparent backgrounds
• composerIcon: Square icon for the chat interface
• brandColor: Hex color code for UI theming

Complete plugin.json Structure

A complete implementation referencing the openai/plugins repository standards appears as follows:

{
  "name": "my-awesome-plugin",
  "version": "1.0.0",
  "description": "Brief tagline describing core functionality",
  "author": {
    "name": "MyCompany",
    "url": "https://mycompany.com"
  },
  "interface": {
    "displayName": "My Awesome Plugin",
    "shortDescription": "One-sentence value proposition under 120 chars",
    "longDescription": "First paragraph hook describing the problem solved.\n\nSecond paragraph explaining the data source, coverage, and API. Include concrete use-cases and sample prompts.\n\nThird paragraph adds reliability details and a call-to-action.",
    "developerName": "MyCompany",
    "category": "Productivity",
    "capabilities": ["search", "export"],
    "defaultPrompt": [
      "Prompt one that showcases a primary feature.",
      "Prompt two highlighting a secondary use-case."
    ],
    "websiteURL": "https://mycompany.com",
    "privacyPolicyURL": "https://mycompany.com/privacy",
    "termsOfServiceURL": "https://mycompany.com/terms",
    "composerIcon": "./assets/icon.png",
    "logo": "./assets/logo.png",
    "logoDark": "./assets/logo-dark.png",
    "brandColor": "#123456"
  }
}

Key Reference Files in openai/plugins

When drafting your OpenAI plugin description, consult these specific files in the repository:

• plugins/quartr/.codex-plugin/plugin.json: Exemplifies well-crafted shortDescription, longDescription, and defaultPrompt arrays
• plugins/zoominfo/.codex-plugin/plugin.json: Demonstrates proper legal URL formatting and category selection
• plugins/**/.codex-plugin/plugin.json: General template structure for metadata files
• README.md: Repository-level guidance on plugin development standards

Summary

• Craft a punchy shortDescription under 120 characters that avoids generic terms and specifies your value proposition
• Structure the longDescription with a hook, data source details, use cases, and call-to-action across 2-4 paragraphs
• Include 2-4 concrete prompts in the defaultPrompt array using natural language under 200 characters
• Select specific categories and populate keywords for improved marketplace searchability
• Provide HTTPS legal URLs and high-resolution branding assets (512×512px) for both light and dark themes
• Reference existing implementations like Quartr and ZoomInfo in the openai/plugins repository as templates

Frequently Asked Questions

What is the character limit for an OpenAI plugin short description?

The shortDescription field should not exceed 120 characters to display properly in the ChatGPT Marketplace listings. This constraint ensures the text remains readable in compact UI views while forcing developers to distill their value proposition into a single sentence without generic filler words like "tool" or "service".

How should I format the long description in plugin.json?

Format the longDescription as plain text using \n\n to separate paragraphs. Include 2-4 paragraphs (300-500 words) covering: what data sources the plugin accesses, specific use cases with natural language examples, any limitations or latency considerations, and a call-to-action directing users to the default prompts.

Do I need to include both light and dark logos?

Yes, you must provide both logo and logoDark paths in your interface configuration. The ChatGPT Marketplace supports dark mode, and providing both variants ensures consistent branding. Use 512×512px PNG or SVG files with transparent backgrounds for optimal rendering across different themes.

What makes a good default prompt for an OpenAI plugin?

Effective default prompts showcase specific functionality using natural language without code syntax. Each prompt should be under 200 characters, demonstrate a concrete use case (e.g., "Compare recurring analyst question themes from the last two earnings calls"), and require no modification from the user to execute successfully.

{
  "mcpServers": {
    "instagit": {
      "command": "npx",
      "args": ["-y", "instagit@latest"]
    }
  }
}