Prompt Engineering for Copilot Chat (VS Code)

 

Prompt engineering is about how you ask Copilot for help — better prompts = better responses.

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✅ Key Strategies for Better Prompts

1. Provide Context

• Open relevant files in VS Code.

• Use top-level comments and descriptive function names.

• Set includes/imports explicitly to guide Copilot's suggestions.

• Use meaningful variable names and function scopes.

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2. Use Chat Participants & Slash Commands

Chat Participants

• @workspace — Ask questions about your open project.

• @vscode — Ask about VS Code features/extensions.

• @terminal — Run or explain shell commands.

Slash Commands

• /explain — Explain code.

• /fix — Suggest fixes.

• /tests — Generate test cases.

• /optimize — Suggest improvements.

🔹 Example:
/fix why is #auth.service.ts throwing "undefined" on line 24?

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3. Add Specific Context with # Variables

Use #filename, #folder, or #symbol to focus on specific areas of your code.

🔹 Examples:

• “Summarize the changes in #changes.”

• “What does the function #getUserData do?”

• “Improve logging in #server.js using Winston.”

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4. Break Down Tasks

Avoid huge multi-step prompts. Instead, guide Copilot one step at a time.

🔹 Bad:

“Create an Express app with Pug, TypeScript, MongoDB, and a product page.”

🔹 Better:

1. “Set up a basic Express app using TypeScript and Pug.”

2. “Add a /products route that renders a view.”

3. “Connect to MongoDB using Mongoose and fetch product data.”

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5. Use High-Quality Example Code

• Paste small, relevant examples to prime Copilot’s suggestions.

• Use current or desired libraries in the snippet.

• Delete the sample after Copilot “gets it.”

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6. Iterate on Results

You can always ask for:

• A different approach (“avoid recursion”)

• Better naming (“use camelCase”)

• Performance improvements

• Alignment with your coding style

🔹 Prompt:

“Rewrite this function using a loop instead of recursion.”

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7. Maintain Quality

• Copilot mimics your code quality.

• Clean, idiomatic code = better suggestions.

• Consider disabling Copilot during “quick and dirty” coding.

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📚 Example Prompts

Task	Prompt
Add a route	“Add a POST /products route in #api.ts using Express.”
Refactor code	“Refactor #invoice.js to remove duplicate logic.”
Debug	“/fix error in #auth.service.ts on line 24”
Learn code	“/explain how JWT validation works in #auth.ts”
Generate tests	“/tests for validateInput in #form-utils.js”

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💬 Quick Reference: Prompt Formula

Intent + Context + Constraint

🧾 Example:

“Create a pagination helper in #utils.js that limits to 10 items per page using plain JavaScript.”

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🔗 Learn More

• GitHub Copilot Docs

• VS Code Copilot Guide

• Prompting Best Practices