import type { McpServer } from '@modelcontextprotocol/sdk/server/mcp.js';
import type { Resend } from 'resend';
import { z } from 'zod';
const webhookEventSchema = z.enum([
'email.sent',
'email.scheduled',
'email.delivered',
'email.delivery_delayed',
'email.complained',
'email.bounced',
'email.opened',
'email.clicked',
'email.received',
'email.failed',
'email.suppressed',
'contact.created',
'contact.updated',
'contact.deleted',
'domain.created',
'domain.updated',
'domain.deleted',
]);
export function addWebhookTools(server: McpServer, resend: Resend) {
server.registerTool(
'create-webhook',
{
title: 'Create Webhook',
description:
'Create a new webhook in Resend. A webhook allows you to receive notifications at a specified URL when certain events occur (e.g. email.sent, email.delivered, email.bounced).',
inputSchema: {
endpoint: z.url().describe('The URL where webhook events will be sent'),
events: webhookEventSchema
.array()
.min(1)
.describe('Array of event types to subscribe to'),
},
},
async ({ endpoint, events }) => {
console.error(
`Debug - Creating webhook for endpoint: ${endpoint} with events: ${events.join(', ')}`,
);
const response = await resend.webhooks.create({ endpoint, events });
if (response.error) {
throw new Error(
`Failed to create webhook: ${JSON.stringify(response.error)}`,
);
}
const created = response.data;
return {
content: [
{ type: 'text', text: 'Webhook created successfully.' },
{
type: 'text',
text: `ID: ${created.id}\nSigning Secret: ${created.signing_secret}`,
},
{
type: 'text',
text: 'IMPORTANT: Make sure to tell the user the signing secret — they will need it to verify webhook payloads and it cannot be retrieved again later.',
},
],
};
},
);
server.registerTool(
'list-webhooks',
{
title: 'List Webhooks',
description:
'List all webhooks from Resend. Use to get webhook IDs and see which endpoints and events are configured. Not for listing emails, segments, or broadcasts.',
inputSchema: {},
},
async () => {
console.error('Debug - Listing webhooks');
const response = await resend.webhooks.list();
if (response.error) {
throw new Error(
`Failed to list webhooks: ${JSON.stringify(response.error)}`,
);
}
const webhooks = response.data.data;
return {
content: [
{
type: 'text',
text: `Found ${webhooks.length} webhook${webhooks.length === 1 ? '' : 's'}${webhooks.length === 0 ? '.' : ':'}`,
},
...webhooks.map(({ id, endpoint, status, events, created_at }) => ({
type: 'text' as const,
text: `Endpoint: ${endpoint}\nStatus: ${status}\nEvents: ${events?.join(', ') ?? 'none'}\nID: ${id}\nCreated at: ${created_at}`,
})),
...(webhooks.length === 0
? []
: [
{
type: 'text' as const,
text: "Don't bother telling the user the IDs or creation dates unless they ask for them.",
},
]),
],
};
},
);
server.registerTool(
'get-webhook',
{
title: 'Get Webhook',
description: 'Get a webhook by ID from Resend.',
inputSchema: {
webhookId: z.string().nonempty().describe('Webhook ID'),
},
},
async ({ webhookId }) => {
console.error(`Debug - Getting webhook with id: ${webhookId}`);
const response = await resend.webhooks.get(webhookId);
if (response.error) {
throw new Error(
`Failed to get webhook: ${JSON.stringify(response.error)}`,
);
}
const webhook = response.data;
return {
content: [
{
type: 'text',
text: `Endpoint: ${webhook.endpoint}\nStatus: ${webhook.status}\nEvents: ${webhook.events?.join(', ') ?? 'none'}\nID: ${webhook.id}\nCreated at: ${webhook.created_at}\nSigning Secret: ${webhook.signing_secret}`,
},
],
};
},
);
server.registerTool(
'update-webhook',
{
title: 'Update Webhook',
description:
'Update an existing webhook in Resend. You can change the endpoint URL, subscribed events, or enable/disable the webhook.',
inputSchema: {
webhookId: z.string().nonempty().describe('Webhook ID'),
endpoint: z
.url()
.optional()
.describe('New URL where webhook events will be sent'),
events: webhookEventSchema
.array()
.min(1)
.optional()
.describe('New array of event types to subscribe to'),
status: z
.enum(['enabled', 'disabled'])
.optional()
.describe('Webhook status'),
},
},
async ({ webhookId, endpoint, events, status }) => {
console.error(`Debug - Updating webhook with id: ${webhookId}`);
const response = await resend.webhooks.update(webhookId, {
endpoint,
events,
status,
});
if (response.error) {
throw new Error(
`Failed to update webhook: ${JSON.stringify(response.error)}`,
);
}
return {
content: [
{ type: 'text', text: 'Webhook updated successfully.' },
{ type: 'text', text: `ID: ${response.data.id}` },
{
type: 'text',
text: "Don't bother telling the user the ID unless they ask for it.",
},
],
};
},
);
server.registerTool(
'remove-webhook',
{
title: 'Remove Webhook',
description:
'Remove a webhook by ID from Resend. Before using this tool, you MUST double-check with the user that they want to remove this webhook. Reference the ENDPOINT of the webhook when double-checking, and warn the user that removing a webhook is irreversible. You may only use this tool if the user explicitly confirms they want to remove the webhook after you double-check.',
inputSchema: {
webhookId: z.string().nonempty().describe('Webhook ID'),
},
},
async ({ webhookId }) => {
console.error(`Debug - Removing webhook with id: ${webhookId}`);
const response = await resend.webhooks.remove(webhookId);
if (response.error) {
throw new Error(
`Failed to remove webhook: ${JSON.stringify(response.error)}`,
);
}
return {
content: [
{ type: 'text', text: 'Webhook removed successfully.' },
{ type: 'text', text: `ID: ${response.data.id}` },
],
};
},
);
}
