import type { McpServer } from '@modelcontextprotocol/sdk/server/mcp.js';
import type { Resend } from 'resend';
import { z } from 'zod';
export function addTopicTools(server: McpServer, resend: Resend) {
server.registerTool(
'create-topic',
{
title: 'Create Topic',
description:
'Create a new topic in Resend. Topics allow contacts to manage their subscription preferences for different types of emails.',
inputSchema: {
name: z
.string()
.nonempty()
.max(50)
.describe('Topic name (max 50 characters)'),
defaultSubscription: z
.enum(['opt_in', 'opt_out'])
.describe(
'Default subscription preference for new contacts. Cannot be modified after creation.',
),
description: z
.string()
.max(200)
.optional()
.describe('Topic description (max 200 characters)'),
},
},
async ({ name, defaultSubscription, description }) => {
console.error(`Debug - Creating topic with name: ${name}`);
const response = await resend.topics.create({
name,
defaultSubscription,
...(description && { description }),
});
if (response.error) {
throw new Error(
`Failed to create topic: ${JSON.stringify(response.error)}`,
);
}
const created = response.data;
return {
content: [
{ type: 'text', text: 'Topic created successfully.' },
{ type: 'text', text: `Name: ${name}\nID: ${created.id}` },
{
type: 'text',
text: "Don't bother telling the user the ID unless they ask for it.",
},
],
};
},
);
server.registerTool(
'list-topics',
{
title: 'List Topics',
description:
'List all topics from Resend. This tool is useful for getting topic IDs to use with other tools like send-email.',
inputSchema: {},
},
async () => {
console.error('Debug - Listing topics');
const response = await resend.topics.list();
if (response.error) {
throw new Error(
`Failed to list topics: ${JSON.stringify(response.error)}`,
);
}
const topics = response.data.data;
return {
content: [
{
type: 'text',
text: `Found ${topics.length} topic${topics.length === 1 ? '' : 's'}${topics.length === 0 ? '.' : ':'}`,
},
...topics.map((topic) => {
const t = topic as unknown as {
visibility?: string;
};
const defaultSub = topic.default_subscription;
const visibility = t.visibility;
return {
type: 'text' as const,
text: `Name: ${topic.name}\nID: ${topic.id}\nDescription: ${topic.description || '(none)'}\nDefault subscription: ${defaultSub}\nVisibility: ${visibility ?? '(unknown)'}`,
};
}),
...(topics.length === 0
? []
: [
{
type: 'text' as const,
text: "Don't bother telling the user the IDs unless they ask for them.",
},
]),
],
};
},
);
server.registerTool(
'get-topic',
{
title: 'Get Topic',
description: 'Get a topic by ID from Resend.',
inputSchema: {
id: z.string().nonempty().describe('Topic ID'),
},
},
async ({ id }) => {
console.error(`Debug - Getting topic with id: ${id}`);
const response = await resend.topics.get(id);
if (response.error) {
throw new Error(
`Failed to get topic: ${JSON.stringify(response.error)}`,
);
}
const topic = response.data;
const t = topic as unknown as {
visibility?: string;
};
const defaultSub = topic.default_subscription;
const visibility = t.visibility;
return {
content: [
{
type: 'text',
text: `Name: ${topic.name}\nID: ${topic.id}\nDescription: ${topic.description || '(none)'}\nDefault subscription: ${defaultSub}\nVisibility: ${visibility ?? '(unknown)'}\nCreated at: ${topic.created_at}`,
},
],
};
},
);
server.registerTool(
'update-topic',
{
title: 'Update Topic',
description:
'Update an existing topic in Resend. Note: defaultSubscription cannot be modified after creation.',
inputSchema: {
id: z.string().nonempty().describe('Topic ID'),
name: z
.string()
.nonempty()
.max(50)
.optional()
.describe('New topic name (max 50 characters)'),
description: z
.string()
.max(200)
.optional()
.describe('New topic description (max 200 characters)'),
},
},
async ({ id, name, description }) => {
console.error(`Debug - Updating topic with id: ${id}`);
const response = await resend.topics.update({
id,
...(name && { name }),
...(description && { description }),
});
if (response.error) {
throw new Error(
`Failed to update topic: ${JSON.stringify(response.error)}`,
);
}
return {
content: [
{ type: 'text', text: 'Topic updated successfully.' },
{ type: 'text', text: `ID: ${response.data.id}` },
],
};
},
);
server.registerTool(
'remove-topic',
{
title: 'Remove Topic',
description:
'Remove a topic by ID from Resend. Before using this tool, you MUST double-check with the user that they want to remove this topic. Reference the NAME of the topic when double-checking, and warn the user that removing a topic is irreversible. You may only use this tool if the user explicitly confirms they want to remove the topic after you double-check.',
inputSchema: {
id: z.string().nonempty().describe('Topic ID'),
},
},
async ({ id }) => {
console.error(`Debug - Removing topic with id: ${id}`);
const response = await resend.topics.remove(id);
if (response.error) {
throw new Error(
`Failed to remove topic: ${JSON.stringify(response.error)}`,
);
}
return {
content: [
{ type: 'text', text: 'Topic removed successfully.' },
{ type: 'text', text: `ID: ${response.data.id}` },
],
};
},
);
}
