import type { McpServer } from '@modelcontextprotocol/sdk/server/mcp.js';
import type { Resend } from 'resend';
import { z } from 'zod';
export function addBroadcastTools(
server: McpServer,
resend: Resend,
{
senderEmailAddress,
replierEmailAddresses,
}: {
senderEmailAddress?: string;
replierEmailAddresses: string[];
},
) {
server.tool(
'create-broadcast',
'Create a new broadcast email to an audience.',
{
name: z
.string()
.nonempty()
.describe(
'Name for the broadcast. If the user does not provide a name, go ahead and create a descriptive name for them, based on the email subject/content and the context of your conversation.',
),
audienceId: z.string().nonempty().describe('Audience ID to send to'),
subject: z.string().nonempty().describe('Email subject'),
text: z
.string()
.nonempty()
.describe(
'Plain text version of the email content. The following placeholders may be used to personalize the email content: {{{FIRST_NAME|fallback}}}, {{{LAST_NAME|fallback}}}, {{{EMAIL}}}, {{{RESEND_UNSUBSCRIBE_URL}}}',
),
html: z
.string()
.optional()
.describe(
'HTML version of the email content. The following placeholders may be used to personalize the email content: {{{FIRST_NAME|fallback}}}, {{{LAST_NAME|fallback}}}, {{{EMAIL}}}, {{{RESEND_UNSUBSCRIBE_URL}}}',
),
previewText: z.string().optional().describe('Preview text for the email'),
...(!senderEmailAddress
? {
from: z.string().email().nonempty().describe('From email address'),
}
: {}),
...(replierEmailAddresses.length === 0
? {
replyTo: z
.string()
.email()
.array()
.optional()
.describe('Reply-to email address(es)'),
}
: {}),
},
async ({
name,
audienceId,
subject,
text,
html,
previewText,
from,
replyTo,
}) => {
console.error(
`Debug - Creating broadcast: ${name ?? '<no-name>'} to audience: ${audienceId}`,
);
const fromEmailAddress = from ?? senderEmailAddress;
const replyToEmailAddresses = replyTo ?? replierEmailAddresses;
// Type check on from, since "from" is optionally included in the arguments schema
// This should never happen.
if (typeof fromEmailAddress !== 'string') {
throw new Error('from argument must be provided.');
}
// Similar type check for "reply-to" email addresses.
if (
typeof replyToEmailAddresses !== 'string' &&
!Array.isArray(replyToEmailAddresses)
) {
throw new Error('replyTo argument must be provided.');
}
const response = await resend.broadcasts.create({
name,
audienceId,
subject,
text,
html,
previewText,
from: fromEmailAddress,
replyTo: replyToEmailAddresses,
});
if (response.error) {
throw new Error(
`Failed to create broadcast: ${JSON.stringify(response.error)}`,
);
}
return {
content: [
{ type: 'text', text: 'Broadcast created 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.tool(
'send-broadcast',
'Send a broadcast email by ID. You may optionally schedule the send.',
{
id: z.string().nonempty().describe('Broadcast ID'),
scheduledAt: z
.string()
.optional()
.describe(
'When to send the broadcast. Value may be in ISO 8601 format (e.g., 2024-08-05T11:52:01.858Z) or in natural language (e.g., "tomorrow at 10am", "in 2 hours", "next day at 9am PST", "Friday at 3pm ET"). If not provided, the broadcast will be sent immediately.',
),
},
async ({ id, scheduledAt }) => {
console.error(`Debug - Sending broadcast with id: ${id}`);
const response = await resend.broadcasts.send(id, { scheduledAt });
if (response.error) {
throw new Error(
`Failed to send broadcast: ${JSON.stringify(response.error)}`,
);
}
return {
content: [
{ type: 'text', text: 'Broadcast sent 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.tool(
'list-broadcasts',
'List all broadcasts. Use this to find broadcast IDs or names.',
{},
async () => {
console.error('Debug - Listing broadcasts');
const response = await resend.broadcasts.list();
if (response.error) {
throw new Error(
`Failed to list broadcasts: ${JSON.stringify(response.error)}`,
);
}
const broadcasts = response.data.data;
return {
content: [
{
type: 'text',
text: `Found ${broadcasts.length} broadcast${broadcasts.length === 1 ? '' : 's'}${broadcasts.length === 0 ? '.' : ':'}`,
},
...broadcasts.map(
({
name,
id,
audience_id,
status,
created_at,
scheduled_at,
sent_at,
}) => ({
type: 'text' as const,
text: [
`ID: ${id}`,
`Name: ${name}`,
audience_id !== null && `Audience ID: ${audience_id}`,
`Status: ${status}`,
`Created at: ${created_at}`,
scheduled_at !== null && `Scheduled at: ${scheduled_at}`,
sent_at !== null && `Sent at: ${sent_at}`,
]
.filter(Boolean)
.join('\n'),
}),
),
],
};
},
);
server.tool(
'get-broadcast',
'Get a broadcast by ID.',
{
id: z.string().nonempty().describe('Broadcast ID'),
},
async ({ id }) => {
console.error(`Debug - Getting broadcast with id: ${id}`);
const response = await resend.broadcasts.get(id);
if (response.error) {
throw new Error(
`Failed to get broadcast: ${JSON.stringify(response.error)}`,
);
}
const {
id: broadcastId,
name,
audience_id,
from,
subject,
reply_to,
preview_text,
status,
created_at,
scheduled_at,
sent_at,
} = response.data;
return {
content: [
{
type: 'text',
text: [
`ID: ${broadcastId}`,
`Name: ${name}`,
audience_id !== null && `Audience ID: ${audience_id}`,
from !== null && `From: ${from}`,
subject !== null && `Subject: ${subject}`,
reply_to !== null && `Reply-to: ${reply_to.join(', ')}`,
preview_text !== null && `Preview text: ${preview_text}`,
`Status: ${status}`,
`Created at: ${created_at}`,
scheduled_at !== null && `Scheduled at: ${scheduled_at}`,
sent_at !== null && `Sent at: ${sent_at}`,
]
.filter(Boolean)
.join('\n'),
},
],
};
},
);
server.tool(
'remove-broadcast',
'Remove a broadcast by ID. Before using this tool, you MUST double-check with the user that they want to remove this broadcast. Reference the NAME of the broadcast when double-checking, and warn the user that removing a broadcast is irreversible. You may only use this tool if the user explicitly confirms they want to remove the broadcast after you double-check.',
{
id: z.string().nonempty().describe('Broadcast ID'),
},
async ({ id }) => {
console.error(`Debug - Removing broadcast with id: ${id}`);
const response = await resend.broadcasts.remove(id);
if (response.error) {
throw new Error(
`Failed to remove broadcast: ${JSON.stringify(response.error)}`,
);
}
return {
content: [
{ type: 'text', text: 'Broadcast removed successfully.' },
{ type: 'text', text: `ID: ${response.data.id}` },
],
};
},
);
server.tool(
'update-broadcast',
'Update a broadcast by ID.',
{
id: z.string().nonempty().describe('Broadcast ID'),
name: z.string().optional().describe('Name for the broadcast'),
audienceId: z.string().optional().describe('Audience ID to send to'),
from: z.string().email().optional().describe('From email address'),
html: z.string().optional().describe('HTML content of the email'),
text: z.string().optional().describe('Plain text content of the email'),
subject: z.string().optional().describe('Email subject'),
replyTo: z
.string()
.email()
.array()
.optional()
.describe('Reply-to email address(es)'),
previewText: z.string().optional().describe('Preview text for the email'),
},
async ({
id,
name,
audienceId,
from,
html,
text,
subject,
replyTo,
previewText,
}) => {
console.error(`Debug - Updating broadcast with id: ${id}`);
const response = await resend.broadcasts.update(id, {
name,
audienceId,
from,
html,
text,
subject,
replyTo,
previewText,
});
if (response.error) {
throw new Error(
`Failed to update broadcast: ${JSON.stringify(response.error)}`,
);
}
return {
content: [
{ type: 'text', text: 'Broadcast updated successfully.' },
{ type: 'text', text: `ID: ${response.data.id}` },
],
};
},
);
}
