Advanced Topics

Prerequisites

• Completed Modules 1-11
• Comfortable with Copilot CLI basics
• Understanding of CI/CD concepts

Learning Objectives

• Configure environment variables and paths
• Set up Copilot CLI for CI/CD pipelines
• Use advanced command-line flags
• Troubleshoot common issues
• Apply best practices for team workflows

Configuration Hierarchy

Environment Variables
        ↓
XDG_CONFIG_HOME (~/.copilot)
        ↓
Repository Configuration
        ↓
Session Overrides (flags)

Key Directories

Directory	Purpose
~/.copilot/	Default config location
~/.copilot/config.json	User settings
~/.copilot/mcp-config.json	MCP servers
~/.copilot/skills/	Personal skills
.github/	Repository config

Exercise 1: Environment Variables

important

Use COPILOT_GITHUB_TOKEN, GH_TOKEN, or GITHUB_TOKEN (in order of precedence) as the authentication token. These take precedence over previously stored credentials.

Goal: Configure Copilot CLI behavior via environment.

Steps:

1. XDG_CONFIG_HOME - Change config location:

   # Set custom config directory
   export XDG_CONFIG_HOME=/custom/path
   
   # Copilot will now use /custom/path/copilot/
   copilot

2. GITHUB_TOKEN - Authentication for CI/CD:

   export GITHUB_TOKEN="ghp_your_personal_access_token"
   
   # Use in scripts
   copilot -p "Run the test suite" --allow-tool 'shell'

3. GITHUB_ASKPASS - Credential helper:

   # Create a credential helper script
   cat > ~/credential-helper.sh << 'EOF'
   #!/bin/bash
   echo "$COPILOT_TOKEN"
   EOF
   chmod +x ~/credential-helper.sh
   
   export GITHUB_ASKPASS=~/credential-helper.sh
   export COPILOT_TOKEN="your-token"
   
   copilot

4. NO_COLOR - Disable colored output:

   export NO_COLOR=1
   copilot -p "List files"

5. View effective configuration:

   copilot --help | head -50

Expected Outcome: Environment variables customize Copilot behavior.

Exercise 2: CI/CD Integration

Goal: Set up Copilot CLI in automated pipelines.

Steps:

1. GitHub Actions workflow:

   # .github/workflows/copilot-review.yml
   name: Copilot Code Review
   
   on:
     pull_request:
       types: [opened, synchronize]
   
   jobs:
     review:
       runs-on: ubuntu-latest
       steps:
         - uses: actions/checkout@v4
   
         - name: Setup Node.js
           uses: actions/setup-node@v4
           with:
             node-version: '22'
   
         - name: Install Copilot CLI
           run: npm install -g @github/copilot
   
         - name: Run Code Review
           env:
             GITHUB_TOKEN: ${{ secrets.COPILOT_TOKEN }}
           run: |
             copilot -p "Review the changes in this PR and provide feedback" \
               --allow-tool 'shell(git)' \
               --deny-tool 'write' \
               --silent

2. Pre-commit hook:

   # .git/hooks/pre-commit
   #!/bin/bash
   
   # Run Copilot analysis on staged files
   STAGED_FILES=$(git diff --cached --name-only --diff-filter=ACM)
   
   if [ -n "$STAGED_FILES" ]; then
     copilot -p "Review these staged files for issues: $STAGED_FILES" \
       --allow-tool 'shell(cat)' \
       --allow-tool 'shell(git diff)' \
       --deny-tool 'write' \
       --silent
   fi

3. Docker container usage:

   FROM node:22-slim
   
   RUN npm install -g @github/copilot
   
   # Set up config directory
   ENV XDG_CONFIG_HOME=/app/config
   
   WORKDIR /workspace
   
   # Entry point for CI
   ENTRYPOINT ["copilot"]

4. Safe CI flags:

   copilot -p "Your prompt" \
     --allow-tool 'shell(npm test)' \
     --allow-tool 'shell(npm run lint)' \
     --deny-tool 'shell(rm)' \
     --deny-tool 'shell(git push)' \
     --deny-tool 'write' \
     --silent

Expected Outcome: Copilot CLI integrated into automated workflows.

Exercise 3: Advanced Command-Line Flags

Goal: Master all available flags.

Steps:

1. Output control:

   # Silent mode - minimal output
   copilot -p "Count lines of code" --silent
   
   # Export session to markdown
   copilot -p "Analyze project" --share ./analysis.md
   
   # Export to GitHub Gist
   copilot -p "Generate report" --share-gist

2. Tool control:

   # Allow specific tools only
   copilot --available-tools 'shell,read'
   
   # Exclude specific tools
   copilot --excluded-tools 'write,web_fetch'

3. Model selection:

   # Use specific model
   copilot --model gpt-4.1
   
   # Use faster model for simple tasks
   copilot --model gpt-5-mini -p "What time is it?"

4. Session control:

   # Resume last session
   copilot --resume
   
   # Use additional MCP config temporarily
   copilot --additional-mcp-config ./custom-mcp.json

5. View all flags:

   copilot --help

Expected Outcome: Full command-line control over Copilot behavior.

Quick Reference

Configuration Files

File	Purpose	Version Added
~/.copilot/config.json	User settings	Base
~/.copilot/mcp-config.json	MCP servers	Base
~/.copilot/lsp.json	LSP timeout configuration	v0.0.412
~/.copilot/skills/	Personal skills	Base
.github/copilot-instructions.md	Repository instructions	Base

Environment Variables

Variable	Purpose
XDG_CONFIG_HOME	Config directory location
GITHUB_TOKEN	Authentication token
GITHUB_ASKPASS	Credential helper script
NO_COLOR	Disable colored output
COPILOT_DEBUG	Enable debug logging

Command-Line Flags

Flag	Description	Version
-p, --prompt	Programmatic mode prompt	Base
--model	Select AI model	Base
--resume	Resume last session	Base
--yolo	Allow all tools	Base
--allow-tool	Allow specific tool	Base
--deny-tool	Deny specific tool	Base
--silent	Suppress output	Base
--share PATH	Export to markdown	Base
--share-gist	Export to Gist	Base
--additional-mcp-config	Add MCP config	Base
--autopilot	Enable autonomous multi-step execution	v0.0.411
--bash-env	Source BASH_ENV in shell sessions	v0.0.412
--experimental	Enable experimental features	v0.0.413

Shell Mode Access

note

Changed in v0.0.410: Shell mode removed from Shift+Tab cycle.

Method	Description	Version
!	Direct access to shell mode	v0.0.410+
Shift+Tab	Cycle (chat) / (command) only	v0.0.410+

Useful Aliases

# Add to ~/.bashrc or ~/.zshrc

# Quick Copilot start
alias cop='copilot'

# Read-only analysis
alias cop-analyze='copilot --deny-tool write'

# Safe automation mode
alias cop-safe='copilot --allow-tool "shell(cat)" --allow-tool "shell(grep)" --deny-tool write'

# Full autonomy (careful!)
alias cop-yolo='copilot --yolo'

# Resume session
alias cop-resume='copilot --resume'

Next Steps

Continue to Automation Patterns for autopilot mode, fleet command, and LSP configuration.