Server Feature Utilities

​

Protocol Overview

This endpoint provides three server feature utility methods as defined in the MCP 2025-03-26 specification:

1. completion/complete - Argument autocompletion for prompts and resource URIs
2. logging/setLevel - Set minimum log level for server notifications
3. Cursor-based pagination - For paginating large result sets in list operations

All methods use JSON-RPC 2.0 over HTTP with tenant-specific endpoints.

​

Prerequisites

1. Valid OAuth Token - Bearer token from Cognito authentication
2. MCP Session - Initialized via initialize method
3. Tenant Context - Valid tenant path (e.g., /pipedrive/mcp, /hubspot/mcp)

​

Completion Utility

​

completion/complete

Provides argument autocompletion suggestions for prompts and resource URIs. Enables rich, IDE-like experiences where users receive contextual suggestions while entering argument values.

​

Request

{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "completion/complete",
  "params": {
    "ref": {
      "type": "ref/prompt",
      "name": "code_review"
    },
    "argument": {
      "name": "language",
      "value": "py"
    }
  }
}

​

Parameters

​

Response

{
  "jsonrpc": "2.0",
  "id": 1,
  "result": {
    "completion": {
      "values": ["python", "pytorch", "pyside"],
      "total": 3,
      "hasMore": false
    }
  }
}

​

Completion Features

• Prompt Arguments: Contextual suggestions based on argument names (language, type, status, format)
• Resource URIs: URI completion based on available resources
• Maximum Results: Limited to 100 suggestions per request
• Fuzzy Matching: Partial string matching for suggestions

​

Logging Utility

​

logging/setLevel

Sets the minimum log level for server notifications. Uses RFC 5424 standard log levels and controls which notifications/message events are sent to clients.

​

Request

{
  "jsonrpc": "2.0",
  "id": 2,
  "method": "logging/setLevel",
  "params": {
    "level": "info"
  }
}

​

Parameters

​

Response

{
  "jsonrpc": "2.0",
  "id": 2,
  "result": {}
}

​

Log Levels (RFC 5424)

​

Log Message Notifications

Once a level is set, the server sends notifications/message for qualifying log events:

{
  "jsonrpc": "2.0",
  "method": "notifications/message",
  "params": {
    "level": "error",
    "logger": "database",
    "data": {
      "error": "Connection failed",
      "details": {
        "host": "localhost",
        "port": 5432
      }
    }
  }
}

​

Pagination Utility

​

Cursor-based Pagination

Our implementation supports cursor-based pagination for all list operations that may return large result sets. Pagination uses opaque cursor tokens instead of numbered pages.

​

Supported Operations

• resources/list - List available resources
• resources/templates/list - List resource templates
• prompts/list - List available prompts
• tools/list - List available tools

​

Pagination Request

{
  "jsonrpc": "2.0",
  "id": 3,
  "method": "resources/list",
  "params": {
    "cursor": "eyJvZmZzZXQiOjUwLCJwYWdlX3NpemUiOjUwfQ=="
  }
}

​

Pagination Response

{
  "jsonrpc": "2.0",
  "id": 3,
  "result": {
    "resources": [
      {
        "uri": "file:///example.txt",
        "name": "example.txt",
        "mimeType": "text/plain"
      }
    ],
    "nextCursor": "eyJvZmZzZXQiOjEwMCwicGFnZV9zaXplIjo1MH0="
  }
}

​

Pagination Features

• Opaque Cursors: Base64-encoded tokens containing position information
• Default Page Size: 50 items per page
• Maximum Page Size: 100 items per page
• Total Count: Not exposed (cursor-based approach)
• Stable Ordering: Consistent results across pagination requests

​

Pagination Flow

1. First Request: Send list request without cursor parameter
2. Check Next Cursor: Look for nextCursor in response
3. Continue Pagination: Use nextCursor value in subsequent requests
4. End Detection: Missing nextCursor indicates no more results

​

Error Handling

All utilities follow standard JSON-RPC 2.0 error responses:

​

Common Error Codes

​

Error Response Format

{
  "jsonrpc": "2.0",
  "id": 1,
  "error": {
    "code": -32602,
    "message": "Invalid params: missing level parameter"
  }
}

​

Security Considerations

​

Completion Security

• Input validation on all completion parameters
• Rate limiting to prevent abuse
• Access control based on OAuth permissions
• No sensitive data in completion suggestions

​

Logging Security

• Log messages must not contain credentials or secrets
• Personal identifying information is filtered
• Internal system details are sanitized
• Rate limiting prevents log flooding

​

Pagination Security

• Cursor validation prevents injection attacks
• Access control applied to all paginated resources
• Consistent permissions across pagination requests
• Resource filtering based on OAuth scope

​

Implementation Notes

​

Server Capabilities

These utilities are declared in the server’s capabilities during initialization:

{
  "capabilities": {
    "completions": {},
    "logging": {}
  }
}

Note: Pagination is implicit in list operations and does not require a separate capability declaration.

​

Rate Limiting

• Completion: Debounced requests recommended
• Logging: Message emission rate controlled by server
• Pagination: Standard HTTP rate limits apply

​

Client Integration

• Completion: Implement debouncing for real-time suggestions
• Logging: Handle notifications asynchronously
• Pagination: Cache cursors appropriately but do not persist across sessions