GitHub Copilot Chat Deep Dive

What Is Copilot Chat?

GitHub Copilot Chat is an AI assistant built into VS Code. You type natural language, and it helps you write code, answer questions, debug problems, and — with @Solar — build entire prototypes.

Open it with ⌘ Shift I (macOS) or Ctrl Shift I (Windows/Linux).

Modes

Copilot Chat has three modes that control how it interacts with your code:

Mode	What it does	When to use it
Ask	Answers questions, explains code, suggests approaches. Read-only — never edits files.	You want information or guidance without changing anything
Edit	Edits specific files you point it to. Shows a diff for you to accept or reject.	You want targeted changes to one or a few files
Agent	Works autonomously — reads files, runs terminal commands, creates/edits multiple files.	You want Copilot to handle a multi-step task end-to-end (this is what @Solar uses)

Switch modes using the dropdown at the top of the chat panel, or type a message and choose the mode before sending.

Tip for @Solar: Always use Agent mode when working with @Solar. It needs the ability to read your project, run commands, and edit multiple files.

Models

You can choose which AI model powers Copilot Chat:

Model	Strengths
GPT-4o	Fast, good all-round performance
Claude Sonnet	Strong at reasoning and longer tasks
Claude Opus	Most capable for complex multi-step work
Gemini	Google's model — good at code understanding

Switch models using the model selector dropdown at the bottom of the chat input.

Tip: For @Solar prototyping, Claude Sonnet or Claude Opus generally produce the best results. Experiment and see what works for your use case.

Attachments (Context)

Copilot Chat works best when you give it context — information about what you're looking at or working with. You attach context using the # symbol or the paperclip icon.

Attachment	Syntax	What it provides
File	#file:HomePage.tsx	The full contents of a specific file
Selection	Select code, then ask	The highlighted text in your editor
Terminal	#terminal	Recent terminal output (errors, logs)
Browser	#browser	A screenshot of the Simple Browser preview
Codebase	#codebase	Searches your entire project for relevant context
Problems	#problems	Current errors and warnings from the Problems panel
Git changes	#changes	Files modified since your last commit

How to attach

1. Type # in the chat input — a dropdown appears with all available attachments
2. Click the paperclip icon (📎) in the chat input bar
3. Select text in the editor before asking a question — it's automatically included

Tip: The more relevant context you give, the better the response. For @Solar, #browser is especially powerful — it lets Copilot see exactly what your prototype looks like.

Tools & MCP Servers

What are Tools?

Tools are capabilities that Copilot Chat can use in Agent mode. They let the AI go beyond text generation and actually do things:

• Read and write files
• Run terminal commands
• Search your codebase
• Fetch web pages
• Interact with external services

You can see available tools by clicking the toolbox icon (🧰) in the chat input.

What are MCP Servers?

MCP (Model Context Protocol) servers are plugins that give Copilot Chat access to external tools and services. Think of them as "connectors" between Copilot and the outside world.

Examples:

• Figma MCP — lets Copilot read Figma designs and generate code from them
• GitHub MCP — lets Copilot create issues, PRs, and manage repos
• Database MCPs — let Copilot query databases

How MCPs work (simplified)

1. An MCP server is configured in your VS Code settings (usually in .vscode/mcp.json)
2. When you use Agent mode, Copilot discovers the tools provided by the MCP server
3. Copilot can then call those tools to fetch data or perform actions
4. You see what tools Copilot wants to use and can approve or deny each call

You don't need to set up MCPs yourself. Your workspace may already have them configured. The key thing is understanding that when Copilot asks to use a tool like "get Figma design" or "create GitHub issue," it's using an MCP.

Approvals & Autopilot

When Copilot Chat is in Agent mode, it may want to:

• Edit files
• Run terminal commands
• Call external tools (MCPs)

VS Code gives you control over how much autonomy Copilot gets:

Level	What happens
Manual approval (default)	Copilot asks permission for every action. You click "Allow" or "Deny" for each one.
Session trust	After you approve a tool once, it's trusted for the rest of the session.
Autopilot	Copilot runs all actions automatically without asking. Use this when you trust the task (like @Solar prototyping).

To change the approval level:

• Click the dropdown arrow next to the Send button
• Or configure it in Settings → search for "copilot approval"

Tip for @Solar: Enable Autopilot when prototyping with @Solar so it can run commands, edit files, and navigate the preview without interrupting you for each step.

How to "Send" a Message

The way you send a message affects what Copilot does:

Action	How	What it does
Send (Enter)	Press Enter	Sends your message in the current mode (Ask, Edit, or Agent)
New line	Press Shift + Enter	Adds a line break — useful for multi-line prompts
Send to specific mode	Click the dropdown arrow next to Send	Lets you pick Ask/Edit/Agent for just this message

The Send dropdown

The small ▾ arrow next to the Send button reveals options:

• Ask — send as a question (no edits)
• Edit — send as an edit request
• Agent — send as a full agent task

This is useful when you want a quick one-off in a different mode without changing your default.

Putting It All Together

Here's a typical @Solar workflow using everything from this module:

1. Open Copilot Chat (⌘ Shift I)
2. Set Agent mode (dropdown at the top)
3. Select a model (Claude Sonnet recommended)
4. Type your prompt: @solar /initiate a merchant dashboard
5. Enable Autopilot so @Solar can work uninterrupted
6. Attach context when refining: #browser look at the table — make the columns sortable
7. Review changes in the editor — accept or revert as needed

Summary

Concept	Key takeaway
Modes	Ask (read-only), Edit (targeted changes), Agent (autonomous multi-step)
Models	Choose based on task complexity — Claude Sonnet/Opus for @Solar
Attachments	Use # to give Copilot context — #browser and #file are most useful
Tools & MCPs	Agent mode can use tools; MCPs connect to external services
Approvals	Control Copilot's autonomy — use Autopilot for trusted @Solar tasks
Send types	Enter to send, Shift+Enter for new line, dropdown to switch modes per message