@Resource

The @Resource decorator defines a static MCP resource with a fixed URI that can be read by AI clients.

Basic Usage

import { Resource, ResourceContext } from '@frontmcp/sdk';

@Resource({
  name: 'app-config',
  uri: 'config://app',
  mimeType: 'application/json',
  description: 'Application configuration',
})
class AppConfigResource extends ResourceContext {
  async execute(uri: string) {
    return {
      contents: [{
        uri,
        mimeType: 'application/json',
        text: JSON.stringify({ version: '1.0.0', debug: false }),
      }],
    };
  }
}

Signature

function Resource(providedMetadata: ResourceMetadata): ClassDecorator

Configuration Options

Required Properties

Property	Type	Description
name	string	Unique resource identifier
uri	string	Resource URI (must be valid per RFC 3986)

Optional Properties

Property	Type	Description
title	string	Human-readable title
description	string	Resource description
mimeType	string	MIME type (e.g., ‘application/json’)
icons	Icon[]	Icons for display

URI Schemes

Resources can use any valid URI scheme:

// File scheme
@Resource({
  name: 'readme',
  uri: 'file:///docs/README.md',
  mimeType: 'text/markdown',
})

// Custom scheme
@Resource({
  name: 'database-schema',
  uri: 'db://schema/users',
  mimeType: 'application/json',
})

// HTTPS scheme
@Resource({
  name: 'api-spec',
  uri: 'https://api.example.com/openapi.json',
  mimeType: 'application/json',
})

Return Format

Resources must return ReadResourceResult:

interface ReadResourceResult {
  contents: Array<{
    uri: string;
    mimeType?: string;
    text?: string;      // Text content
    blob?: string;      // Base64-encoded binary content
  }>;
}

Text Content

@Resource({ name: 'text-file', uri: 'file://readme.txt' })
class TextResource extends ResourceContext {
  async execute(uri: string) {
    return {
      contents: [{
        uri,
        mimeType: 'text/plain',
        text: 'Hello, World!',
      }],
    };
  }
}

Binary Content

@Resource({ name: 'image', uri: 'file://logo.png', mimeType: 'image/png' })
class ImageResource extends ResourceContext {
  async execute(uri: string) {
    const imageBuffer = await readFile('/path/to/logo.png');
    return {
      contents: [{
        uri,
        mimeType: 'image/png',
        blob: imageBuffer.toString('base64'),
      }],
    };
  }
}

Function-Based Alternative

import { resource } from '@frontmcp/sdk';

const appConfig = resource({
  name: 'app-config',
  uri: 'config://app',
  mimeType: 'application/json',
})((uri, params) => ({
  contents: [{
    uri,
    mimeType: 'application/json',
    text: JSON.stringify({ version: '1.0.0' }),
  }],
}));

Context Methods

The ResourceContext base class provides:

async execute(uri: string, params: Record<string, string>) {
  // Dependency injection
  const db = this.get(DatabaseToken);

  // Logging
  this.logger.info('Reading resource', { uri });

  // Authentication
  const auth = this.getAuthInfo();

  // Access scope
  const tools = this.scope.tools;

  // Error handling
  if (!exists) {
    this.fail(new ResourceNotFoundError(uri));
  }

  // Early return
  this.respond({ contents: [...] });
}

Full Example

import { Resource, ResourceContext, App, FrontMcp } from '@frontmcp/sdk';

@Resource({
  name: 'system-status',
  uri: 'status://system',
  title: 'System Status',
  description: 'Current system health and metrics',
  mimeType: 'application/json',
})
class SystemStatusResource extends ResourceContext {
  async execute(uri: string) {
    this.mark('fetching-metrics');

    const metrics = {
      uptime: process.uptime(),
      memory: process.memoryUsage(),
      timestamp: new Date().toISOString(),
    };

    return {
      contents: [{
        uri,
        mimeType: 'application/json',
        text: JSON.stringify(metrics, null, 2),
      }],
    };
  }
}

@App({
  name: 'monitoring',
  resources: [SystemStatusResource],
})
class MonitoringApp {}

@FrontMcp({
  info: { name: 'Monitor', version: '1.0.0' },
  apps: [MonitoringApp],
})
export default class MonitorServer {}

Related

@ResourceTemplate

Dynamic URI templates

ResourceContext

Context class details

ResourceRegistry

Resource registry API

Resource Errors

Resource-related errors