Prompt Engineering Step 2: Specifying Constraints (Cursor)

Guide Cursor's AI by telling it not only what you want, but also what *rules* or *limitations* to follow. This leads to more precise and useful results.

1. Explicit Instructions in Prompts

Directly state constraints within your prompt using clear language. This works for both Chat (Cmd+L) and Inline Generation (Cmd+K).

Examples:

  • Language Version: "Generate a Python function compatible with version 3.8 to..."
  • Library Usage: "Refactor this data processing logic using Pandas DataFrames, but *do not* use the numpy library directly."
  • Coding Standards: "Write a JavaScript class following standard Airbnb style guide conventions..."
  • Output Format: "Explain the selected code, formatting the output as a markdown list."
  • Things to Avoid: "Implement the login check, avoiding the use of global variables."

Example Prompt (Cmd+K): 

Create a React functional component for a button. Use Tailwind CSS for styling and ensure it accepts an 'onClick' prop. Do not use default HTML button styles.

2. Persistent Constraints: An Introduction to Cursor Rules

Beyond immediate prompt instructions, Cursor offers powerful ways to define more permanent, reusable constraints using Cursor Rules. These are ideal for ensuring consistency across your entire project, such as enforcing coding standards, preferred libraries, or architectural patterns.

There are two main ways to implement these:

  • Project Rules (Modern Approach): Stored in a dedicated .cursor/rules directory within your project, these allow for fine-grained, version-controlled rule sets. They use a special format (MDC) to define various types of rules that can be automatically or manually applied.
  • Legacy .cursorrules File: A single file in your project's root that can also define project-wide guidelines. While still supported, the newer Project Rules system offers more flexibility.

Think of these rules as a way to give the AI a comprehensive "style guide" or "project constitution." You can instruct it to always use specific design patterns, avoid certain anti-patterns, or prefer particular technologies.

We will dive deep into creating, managing, and mastering both Project Rules and the legacy .cursorrules in a dedicated step later in this learning path, specifically in the section on "Mastering Cursor Rules." For now, it's important to know that these mechanisms exist for more robust and persistent AI guidance.

Key Takeaway

Clearly state limitations, requirements, or standards directly in your prompts for immediate tasks. For establishing broader, project-wide consistency and encoding deeper project knowledge, Cursor provides powerful Rule systems (Project Rules and legacy .cursorrules), which you'll learn to master in a subsequent section.

Proceed to Prompting Step 3: Role-Playing