Power Platform MCP Connector Suite

MCP Capabilities in Copilot Studio

• ✅ Tools: Functions that the LLM can call (with user approval)
• ✅ Resources: File-like data that agents can read (must be tool outputs)

• ❌ Prompts: Pre-written templates (prepare for future support)

Connector Generation

• apiDefinition.swagger.json

  with

  x-ms-agentic-protocol: mcp-streamable-1.0

• apiProperties.json

  with connector metadata and authentication

• script.csx

  with custom C# transformations for MCP JSON-RPC handling

• readme.md

  with connector documentation

• POST

  /mcp

  endpoint for JSON-RPC 2.0 communication
• McpResponse and McpErrorResponse schema definitions
• Copilot Studio constraint compliance (no reference types, single types)
• Resource integration as tool outputs (Resources and Tools supported; Prompts not yet supported)

Schema Validation & Troubleshooting

• ✅ No reference types (

  $ref

  ) in tool inputs/outputs
• ✅ Single type values only (not

  ["string", "number"]

  )
• ✅ Primitive types: string, number, integer, boolean, array, object
• ✅ Resources as tool outputs, not separate entities
• ✅ Full URIs for all endpoints

• Tools filtered → Remove reference types, use primitives
• Type errors → Single types with validation logic
• Resources unavailable → Include in tool outputs
• Connection failures → Verify

  x-ms-agentic-protocol

  header

Context Variables

• Connector Name: [Display name for the connector]
• Server Purpose: [What the MCP server should accomplish]
• Tools Needed: [List of MCP tools to implement]
• Resources: [Types of resources to provide]
• Authentication: [none, api-key, oauth2, basic]
• Host Environment: [Azure Function, Express.js, etc.]
• Target APIs: [External APIs to integrate with]

Generation Modes

Mode 1: Complete New Connector

Mode 2: Schema Validation

Mode 3: Integration Troubleshooting

Mode 4: Hybrid Connector

Mode 5: Certification Preparation

Mode 6: OAuth Security Hardening

Expected Output

• Swagger 2.0 format with Microsoft extensions
• MCP endpoint:

  POST /mcp

  with proper protocol header
• Compliant schema definitions (primitive types only)
• McpResponse/McpErrorResponse definitions

• Connector metadata and branding (

  iconBrandColor

  required)
• Authentication configuration
• Policy templates for MCP transformations

• JSON-RPC 2.0 message handling
• Request/response transformations
• MCP protocol compliance logic
• Error handling and validation

• Tool registration and execution patterns
• Resource management strategies
• Copilot Studio integration steps
• Testing and validation procedures

Validation Checklist

Technical Compliance

• x-ms-agentic-protocol: mcp-streamable-1.0

  in MCP endpoint
• No reference types in any schema definitions
• All type fields are single types (not arrays)
• Resources included as tool outputs
• JSON-RPC 2.0 compliance in script.csx
• Full URI endpoints throughout
• Clear descriptions for Copilot Studio agents
• Authentication properly configured
• Policy templates for MCP transformations
• Generative Orchestration compatibility

CLI Validation

• paconn validate:

  paconn validate --api-def apiDefinition.swagger.json

  passes without errors
• pac CLI ready: Connector can be created/updated with

  pac connector create/update

• Script validation: script.csx passes automatic validation during pac CLI upload
• Package validation:

  ConnectorPackageValidator.ps1

  runs successfully

OAuth and Security Requirements

• OAuth 2.0 Enhanced: Standard OAuth 2.0 with MCP security best practices implementation
• Token Validation: Implement token audience validation to prevent passthrough attacks
• Custom Security Logic: Enhanced validation in script.csx for MCP compliance
• State Parameter Protection: Secure state parameters for CSRF prevention
• HTTPS Enforcement: All production endpoints use HTTPS only
• MCP Security Practices: Implement confused deputy attack prevention within OAuth 2.0

Certification Requirements

• Complete metadata: settings.json with product and service information
• Icon compliance: PNG format, 230x230 or 500x500 dimensions
• Documentation: Certification-ready readme with comprehensive examples
• Security compliance: OAuth 2.0 enhanced with MCP security practices, privacy policy
• Authentication flow: OAuth 2.0 with custom security validation properly configured

Example Usage

Mode: Complete New Connector
Connector Name: Customer Analytics MCP
Server Purpose: Customer data analysis and insights
Tools Needed:
  - searchCustomers: Find customers by criteria
  - getCustomerProfile: Retrieve detailed customer data
  - analyzeCustomerTrends: Generate trend analysis
Resources:
  - Customer profiles (JSON data)
  - Analysis reports (structured data)
Authentication: oauth2
Host Environment: Azure Function
Target APIs: CRM REST API