MCP M365 Copilot

MCP-based M365 Copilot Development Guidelines

Core Principles

Model Context Protocol First

• Leverage MCP servers for external system integration
• Import tools from server endpoints, not manual definitions
• Let MCP handle schema discovery and function generation
• Use point-and-click tool selection in Agents Toolkit

Declarative Over Imperative

• Define agent behavior through configuration, not code
• Use declarativeAgent.json for instructions and capabilities
• Specify tools and actions in ai-plugin.json
• Configure MCP servers in mcp.json

Security and Governance

• Always use OAuth 2.0 or SSO for authentication
• Follow principle of least privilege for tool selection
• Validate MCP server endpoints are secure
• Review compliance requirements before deployment

User-Centric Design

• Create adaptive cards for rich visual responses
• Provide clear conversation starters
• Design for responsive experience across hubs
• Test thoroughly before organizational deployment

MCP Server Design

Server Selection

Choose MCP servers that:

• Expose relevant tools for user tasks
• Support secure authentication (OAuth 2.0, SSO)
• Provide reliable uptime and performance
• Follow MCP specification standards
• Return well-structured response data

Tool Import Strategy

• Import only necessary tools (avoid over-scoping)
• Group related tools from same server
• Test each tool individually before combining
• Consider token limits when selecting multiple tools

Authentication Configuration

OAuth 2.0 Static Registration:

{
  "type": "OAuthPluginVault",
  "reference_id": "YOUR_AUTH_ID",
  "client_id": "github_client_id",
  "client_secret": "github_client_secret",
  "authorization_url": "https://github.com/login/oauth/authorize",
  "token_url": "https://github.com/login/oauth/access_token",
  "scope": "repo read:user"
}

SSO (Microsoft Entra ID):

{
  "type": "OAuthPluginVault",
  "reference_id": "sso_auth",
  "authorization_url": "https://login.microsoftonline.com/common/oauth2/v2.0/authorize",
  "token_url": "https://login.microsoftonline.com/common/oauth2/v2.0/token",
  "scope": "User.Read"
}

File Organization

Project Structure

project-root/
├── appPackage/
│   ├── manifest.json           # Teams app manifest
│   ├── declarativeAgent.json   # Agent config (instructions, capabilities)
│   ├── ai-plugin.json          # API plugin definition
│   ├── color.png               # App icon color
│   └── outline.png             # App icon outline
├── .vscode/
│   └── mcp.json               # MCP server configuration
├── .env.local                  # Credentials (NEVER commit)
└── teamsapp.yml               # Teams Toolkit config

Critical Files

declarativeAgent.json:

• Agent name and description
• Instructions for behavior
• Conversation starters
• Capabilities (actions from plugins)

ai-plugin.json:

• MCP server tools import
• Response semantics (data_path, properties)
• Static adaptive card templates
• Function definitions (auto-generated)

mcp.json:

• MCP server URL
• Server metadata endpoint
• Authentication reference

.env.local:

• OAuth client credentials
• API keys and secrets
• Environment-specific config
• CRITICAL: Add to .gitignore

Response Semantics Best Practices

Data Path Configuration

Use JSONPath to extract relevant data:

{
  "data_path": "$.items[*]",
  "properties": {
    "title": "$.name",
    "subtitle": "$.description", 
    "url": "$.html_url"
  }
}

Template Selection

For dynamic templates:

{
  "data_path": "$",
  "template_selector": "$.templateType",
  "properties": {
    "title": "$.title",
    "url": "$.url"
  }
}

Static Templates

Define in ai-plugin.json for consistent formatting:

• Use when all responses follow same structure
• Better performance than dynamic templates
• Easier to maintain and version control

Adaptive Card Guidelines

Design Principles

• Single-column layout: Stack elements vertically
• Flexible widths: Use "stretch" or "auto", not fixed pixels
• Responsive design: Test in Chat, Teams, Outlook
• Minimal complexity: Keep cards simple and scannable

Template Language Patterns

Conditionals:

{
  "type": "TextBlock",
  "text": "${if(status == 'active', '✅ Active', '❌ Inactive')}"
}

Data Binding:

{
  "type": "TextBlock",
  "text": "${title}",
  "weight": "bolder"
}

Number Formatting:

{
  "type": "TextBlock",
  "text": "Score: ${formatNumber(score, 0)}"
}

Conditional Rendering:

{
  "type": "Container",
  "$when": "${count(items) > 0}",
  "items": [ ... ]
}

Card Elements Usage

• TextBlock: Titles, descriptions, metadata
• FactSet: Key-value pairs (status, dates, IDs)
• Image: Icons, thumbnails (use size: "small")
• Container: Grouping related content
• ActionSet: Buttons for follow-up actions

Testing and Deployment

Local Testing Workflow

1. Provision: Teams Toolkit → Provision
2. Deploy: Teams Toolkit → Deploy
3. Sideload: App uploaded to Teams
4. Test: Visit m365.cloud.microsoft/chat
5. Iterate: Fix issues and re-deploy

Pre-Deployment Checklist

• All MCP server tools tested individually
• Authentication flow works end-to-end
• Adaptive cards render correctly across hubs
• Response semantics extract expected data
• Error handling provides clear messages
• Conversation starters are relevant and clear
• Agent instructions guide proper behavior
• Compliance and security reviewed

Deployment Options

Organization Deployment:

• IT admin deploys to all or selected users
• Requires approval in Microsoft 365 admin center
• Best for internal business agents

Agent Store:

• Submit to Partner Center for validation
• Public availability to all Copilot users
• Requires rigorous security review

Common Patterns

Multi-Tool Agent

Import tools from multiple MCP servers:

{
  "mcpServers": {
    "github": {
      "url": "https://github-mcp.example.com"
    },
    "jira": {
      "url": "https://jira-mcp.example.com"
    }
  }
}

Search and Display

1. Tool retrieves data from MCP server
2. Response semantics extract relevant fields
3. Adaptive card displays formatted results
4. User can take action from card buttons

Authenticated Actions

1. User triggers tool requiring auth
2. OAuth flow redirects for consent
3. Access token stored in plugin vault
4. Subsequent requests use stored token

Error Handling

MCP Server Errors

• Provide clear error messages in agent responses
• Fall back to alternative tools if available
• Log errors for debugging
• Guide user to retry or alternative approach

Authentication Failures

• Check OAuth credentials in .env.local
• Verify scopes match required permissions
• Test auth flow outside Copilot first
• Ensure token refresh logic works

Response Parsing Failures

• Validate JSONPath expressions in response semantics
• Handle missing or null data gracefully
• Provide default values where appropriate
• Test with varied API responses

Performance Optimization

Tool Selection

• Import only necessary tools (reduces token usage)
• Avoid redundant tools from multiple servers
• Test impact of each tool on response time

Response Size

• Use data_path to filter unnecessary data
• Limit result sets where possible
• Consider pagination for large datasets
• Keep adaptive cards lightweight

Caching Strategy

• MCP servers should cache where appropriate
• Agent responses may be cached by M365
• Consider cache invalidation for time-sensitive data

Security Best Practices

Credential Management

• NEVER commit .env.local to source control
• Use environment variables for all secrets
• Rotate OAuth credentials regularly
• Use separate credentials for dev/prod

Data Privacy

• Only request minimum necessary scopes
• Avoid logging sensitive user data
• Review data residency requirements
• Follow compliance policies (GDPR, etc.)

Server Validation

• Verify MCP server is trusted and secure
• Check HTTPS endpoints only
• Review server's privacy policy
• Test for injection vulnerabilities

Governance and Compliance

Admin Controls

Agents can be:

• Blocked: Prevented from use
• Deployed: Assigned to specific users/groups
• Published: Made available organization-wide

Monitoring

Track:

• Agent usage and adoption
• Error rates and performance
• User feedback and satisfaction
• Security incidents

Audit Requirements

Maintain:

• Change history for agent configurations
• Access logs for sensitive operations
• Approval records for deployments
• Compliance attestations

Resources and References

Official Documentation

• Build Declarative Agents with MCP (DevBlogs)
• Build MCP Plugins (Learn)
• API Plugin Adaptive Cards (Learn)
• Manage Copilot Agents (Learn)

Tools and SDKs

• Microsoft 365 Agents Toolkit (VS Code extension v6.3.x+)
• Teams Toolkit for agent packaging
• Adaptive Cards Designer
• MCP specification documentation

Partner Examples

• monday.com: Task management integration
• Canva: Design automation
• Sitecore: Content management