# MCP Resources
This directory contains MCP resource implementations following the [MCP 2025-06-18 specification](https://modelcontextprotocol.io/specification/2025-06-18/server/resources).
## Overview
Resources provide read-only data that MCP clients can access. Unlike tools (which execute actions), resources are static or dynamic data sources identified by URIs.
## Available Resources
| Resource | URI | Description | MIME Type |
| ------------------ | ---------------------- | ------------------------------- | --------------- |
| Echo Documentation | `echo://documentation` | Documentation for the echo tool | `text/markdown` |
## Resource Templates
Resource templates use [RFC 6570 URI Templates](https://datatracker.ietf.org/doc/html/rfc6570) for parameterized access:
| Template | URI Pattern | Description | MIME Type |
| ----------- | -------------------------- | ----------------------------------- | ------------------ |
| Echo Result | `echo://result/{resultId}` | Access echo operation results by ID | `application/json` |
## Creating Resources
### Static Resources
Use `ResourceBuilder` for resources with fixed URIs:
```typescript
import { ResourceBuilder } from '@/resources/types';
export const myResource = new ResourceBuilder('myscheme://path')
.name('Resource Name')
.title('Human-Readable Title')
.description('Description of the resource')
.mimeType('text/plain')
.annotations({
audience: ['user', 'assistant'],
priority: 0.7,
})
.readImplementation(async (uri, context) => ({
contents: [{ uri, mimeType: 'text/plain', text: 'Content here' }],
}))
.build();
```
### Resource Templates
Use `ResourceTemplateBuilder` for parameterized resources:
```typescript
import { ResourceTemplateBuilder } from '@/resources/types';
export const myTemplate = new ResourceTemplateBuilder('myscheme://item/{id}')
.name('Item Resource')
.description('Access items by ID')
.mimeType('application/json')
.readImplementation(async (uri, context) => {
const idMatch = /myscheme:\/\/item\/(.+)/.exec(uri);
const id = idMatch?.[1] ?? 'unknown';
return {
contents: [
{ uri, mimeType: 'application/json', text: JSON.stringify({ id }) },
],
};
})
.build();
```
## Registration
Resources are automatically loaded by `resourceLoader.loadAllResources()` during server initialization. To add a new resource:
1. Create the resource in a subdirectory (e.g., `src/resources/myresource/index.ts`)
2. Export the resource from `src/resources/index.ts`
3. Register it in `src/resources/loader.ts`
## Annotations
Per MCP 2025-06-18, resources support the following annotations:
| Annotation | Type | Description |
| -------------- | --------------------------- | ----------------------------------------- |
| `audience` | `('user' \| 'assistant')[]` | Who the content is intended for |
| `priority` | `number` (0.0-1.0) | Relative importance (1 = most, 0 = least) |
| `lastModified` | `string` (ISO 8601) | When the resource was last modified |
## Content Types
Resources can return different content types:
- **Text content**: Plain text, markdown, or other text formats
- **Binary content**: Base64-encoded binary data (via `blob` field)
## Directory Structure
```
src/resources/
├── echo/
│ └── index.ts # Echo resource and template implementations
├── index.ts # Re-exports all resource modules
├── loader.ts # Resource loader singleton
├── registry.ts # Resource registry for registration/lookup
├── types.ts # TypeScript types and builders
└── README.md # This file
```
