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Resources expose data that clients read by URI. Register one with server.resource(config, handler) — FastMCP auto-detects whether the URI is static or a template by checking for { in the URI string, so there’s no separate method to learn: 
import { FastMCP } from '@prefecthq/fastmcp-ts/server'

const server = new FastMCP({ name: 'my-server' })

// Static resource
server.resource(
  { uri: 'config://settings', description: 'App configuration' },
  () => JSON.stringify({ theme: 'dark', lang: 'en' })
)

// URI template — extracted params are passed to the handler
server.resource(
  { uri: 'user://{id}', description: 'User by ID' },
  ({ id }) => `User #${id}`
)
Static resources are served via resources/list + resources/read. Templates appear in resources/templates/list and are matched at read time using RFC 6570 parameter extraction.

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Template parameter styles

Three styles are supported:
StyleExampleMatches
Simpleuser://{id}A single path segment
Wildcardfiles://{path*}Multiple segments
Querysearch://items{?q,lang}Query-string parameters

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Return values

Handler output is converted to an MCP ReadResourceResult automatically:
Returned valueConversion
stringText content (mimeType defaults to text/plain)
Buffer / Uint8ArrayBase64 blob content (mimeType defaults to application/octet-stream)
Plain object / arrayJSON-serialized text content (mimeType forced to application/json)
null / undefinedEmpty text content
ResourceResult(contents)Passed through as-is
ResourceResult is the escape hatch for full control over the contents array.

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Config fields

FieldBehavior
uriRequired. Static URI or RFC 6570 template
name, title, descriptionDisplay metadata, forwarded in list responses
mimeTypeOverrides the inferred MIME type
sizeSize hint in bytes (static resources only — omitted from template listings, since it’s unknown for parameterized URIs)
annotationsaudience, priority, lastModified — forwarded verbatim
timeoutPer-read timeout in milliseconds
disabledHides the resource and rejects reads
tagsUsed by transforms
authPer-resource authorization check

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Subscriptions

Clients can subscribe to a resource and be notified when it changes. On the client side: 
await client.subscribeResource('config://settings', (uri) => {
  console.log(`${uri} changed — re-read it`)
})

await client.unsubscribeResource('config://settings')
The handler fires whenever the server sends notifications/resources/updated for that URI.

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Dynamic registration

Like tools, resources can be registered before or after run() — adding one to a running server sends notifications/resources/list_changed automatically.