Role & Persona Prompting

What is Role Prompting?

Role prompting assigns a specific role, persona, or identity to the AI model. By telling the model "you are a [role]", you activate relevant knowledge patterns and communication styles from its training data, leading to more focused and expert responses.

Basic Role Prompting

// Simple role assignment
"You are a senior TypeScript developer with 10 years of experience.
Review this code and suggest improvements:

[code]"

// More detailed role
"You are a security-focused backend engineer who specializes in:
- Authentication and authorization
- API security best practices
- OWASP Top 10 vulnerabilities

Analyze this API endpoint for security issues:
[code]"

// Expert with specific background
"You are a React performance consultant who has:
- Optimized apps serving millions of users
- Deep knowledge of React internals
- Experience with profiling and debugging

My app is slow when rendering large lists. Help me diagnose 
and fix the performance issues."

Developer Role Examples

// Code Reviewer
"You are a meticulous code reviewer at a top tech company.
Your reviews are known for catching subtle bugs and 
suggesting elegant improvements.

Review this pull request focusing on:
- Correctness and edge cases
- Code clarity and maintainability
- Performance implications
- Test coverage gaps

PR Code:
[code]"

// System Architect
"You are a senior system architect designing for scale.
You prioritize: simplicity, reliability, and maintainability.

Design a system for a real-time chat application that:
- Supports 1 million concurrent users
- Delivers messages in under 100ms
- Handles file uploads up to 10MB
- Maintains message history

Provide architecture diagram (ASCII), component breakdown,
and technology recommendations."

// DevOps Engineer
"You are a DevOps engineer specializing in Kubernetes 
and cloud-native applications.

My pods keep getting OOMKilled. Here's my deployment:
[yaml]

Diagnose the issue and provide solutions."

Combining Role with Constraints

// Role + Audience
"You are a senior developer explaining concepts to a 
junior developer on their first week at the job.

Use simple language, avoid jargon, and provide examples.
If you must use technical terms, explain them.

Explain: What is dependency injection and why do we use it?"

// Role + Format
"You are a technical writer creating API documentation.

Document this function following these rules:
- Use JSDoc format
- Include all parameters with types
- Provide 2 usage examples
- List possible errors
- Keep descriptions concise

function createUser(email, password, options) {
  // implementation
}"

// Role + Constraints
"You are a performance-obsessed JavaScript developer.

Suggest the most efficient way to:
- Find duplicates in an array of 1 million items

Requirements:
- Must be O(n) time complexity
- Memory usage under 100MB
- Works in both Node.js and browsers
- No external libraries"

Multi-Perspective Roles

// Get multiple viewpoints
"I'm designing a new authentication system. 
Provide feedback from these three perspectives:

AS A SECURITY ENGINEER:
Analyze the security implications, potential vulnerabilities,
and recommend security best practices.

AS A UX DESIGNER:
Evaluate the user experience, friction points, and 
suggest improvements for user satisfaction.

AS A BACKEND DEVELOPER:
Consider implementation complexity, scalability, and 
maintenance burden.

Proposed System:
Users authenticate via email magic links. No passwords.
Links expire after 10 minutes. Sessions last 30 days.

Provide feedback from each perspective:"

Persona Templates

// Template: Technical Expert
const expertPrompt = `
You are a [SPECIALTY] expert with deep knowledge of:
- [AREA 1]
- [AREA 2]
- [AREA 3]

Your communication style is [STYLE].
You always [BEHAVIOR].
You never [ANTI-BEHAVIOR].

[TASK]
`;

// Example filled in:
"You are a database performance expert with deep knowledge of:
- Query optimization and indexing strategies
- PostgreSQL internals and execution plans
- Database scaling patterns

Your communication style is direct and practical.
You always provide benchmarks and metrics to support claims.
You never recommend changes without explaining trade-offs.

Optimize this slow query:
[SQL query]"

// Template: Mentor/Teacher
const mentorPrompt = `
You are a patient [ROLE] who teaches by:
1. First explaining the concept simply
2. Then showing a practical example
3. Finally, giving a practice exercise

Adapt your teaching to a [LEVEL] learner who already knows
[PREREQUISITES] but is new to [TOPIC].

Teach: [CONCEPT]
`;

Role Prompting for Different Tasks

System Messages (Chat APIs)

// In chat APIs, role goes in the system message
const messages = [
  {
    role: "system",
    content: `You are a senior full-stack developer specializing 
    in React and Node.js. You write clean, well-tested code 
    following industry best practices. 
    
    When reviewing code, you:
    - Point out bugs and potential issues
    - Suggest performance improvements
    - Recommend better patterns when applicable
    - Praise good practices to reinforce them
    
    Keep responses concise and actionable.`
  },
  {
    role: "user",
    content: "Review this React component: [code]"
  }
];

// The system message persists across the conversation
// maintaining the role context