Resource Errors

Errors thrown during resource lookup, reading, and URI validation.

Overview

Resource errors cover failures related to MCP resources — not found, read failures, and invalid URIs. ResourceNotFoundError includes a custom toJsonRpcError() method that returns an MCP-compliant JSON-RPC error with the resource URI.

Error Reference

ResourceNotFoundError

Thrown when a requested resource URI does not match any registered resource.

Property	Type	Value
code	string	RESOURCE_NOT_FOUND
statusCode	number	404
isPublic	boolean	true
uri	string	The requested URI
mcpErrorCode	number	-32002

new ResourceNotFoundError(uri: string)

JSON-RPC format:

error.toJsonRpcError();
// { code: -32002, message: "Resource not found: file:///missing.txt", data: { uri: "file:///missing.txt" } }

Example:

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

throw new ResourceNotFoundError('file:///missing.txt');

---

ResourceReadError

Thrown when reading a resource fails. This is an internal error — details are hidden from clients.

Property	Type	Value
code	string	RESOURCE_READ_ERROR
statusCode	number	500
isPublic	boolean	false
originalError	Error | undefined	The underlying cause

new ResourceReadError(uri: string, originalError?: Error)

Example:

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

try {
  const data = await fs.readFile(path);
} catch (error) {
  throw new ResourceReadError('file:///data.json', error);
}

---

InvalidResourceUriError

Thrown when a resource URI does not conform to RFC 3986 or is otherwise malformed.

Property	Type	Value
code	string	INVALID_RESOURCE_URI
statusCode	number	400
isPublic	boolean	true

new InvalidResourceUriError(uri: string, reason?: string)

Example:

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

throw new InvalidResourceUriError('no-scheme', 'URI must have a valid scheme');