Why This Matters

Beginner role prompting (BE-17) is 'act as X'. Intermediate role prompting treats role and constraints as orthogonal knobs you tune for different effects. This systematic approach produces consistent, predictable output.

Concept Explained

Role and constraints are control variables. Role shapes tone/depth/lens; constraints shape behavior (no external libs, must handle null, throw on invalid). Combining them gives you 2D control over output character.

How It Works

Build a matrix: rows = roles (senior engineer, security reviewer, tech writer, mentor), columns = constraint types (no externals, must handle null, prefer functional style, error explicitly). Pick one from each axis per request.

Step-by-Step Tutorial

1. Identify the lens

2. Pick role

3. Pick constraints

4. Combine

5. Iterate

Real-World Example

A team built a role+constraint matrix for code reviews. For security reviews: 'security reviewer, focus on input validation, output as numbered list with severity'. For readability: 'senior engineer, prefer early returns, max 3 levels of nesting, suggest names'. Reviewers picked the right cell per PR; reviews became consistent across the team.

Example Prompts / Commands / Code

              No externals    Must handle null    Prefer pure    Throw on invalid
Security       ✓              ✓                   ✓              ✓
Perf           ✓              -                   ✓              -
Readability    -              -                   ✓              -
Mentor         -              ✓                   -              -

Act as a security reviewer.
Constraints:
- No external libraries.
- Must handle null inputs explicitly.
- Prefer pure functions.
- Throw TypeError on invalid input.

Review the following function. Output as a numbered list with severity (high/med/low), issue, and suggested fix.

Common Mistakes

• Always using the same role — output becomes one-note.
• Mixing too many constraints — model can't satisfy all.
• Not iterating — first role+constraint combo is rarely best.
• Forgetting role and constraints are independent — change one at a time.

Best Practices

• Treat role and constraints as orthogonal knobs.
• Build a matrix for common task types.
• Change one variable at a time when iterating.
• Use 'security reviewer' + 'throw on invalid' for safety-critical code.
• Use 'senior engineer' + 'prefer pure functions' for refactors.

Troubleshooting

Practical Exercise

Professional Challenge

Frequently Asked Questions

Further Reading

• Prompt engineering

Official References

• Prompt engineering

Related lessons: BE-17, IN-02