Mailercloud for AI agents
Mailercloud is an all-in-one email marketing platform for managing contact lists and custom fields for growing businesses sending regular campaigns. Connect it once through Arc0, and your agent, or Claude, ChatGPT and Cursor, can use it through one MCP endpoint, limited to what each user approved.
What agents do in Mailercloud.
Search contacts in a list
Search a list for a contact to confirm their current status, read-only.
Add a custom property
Create a new custom field to capture additional data about contacts going forward.
Check the account's plan limits
Look up the client's current plan before adding a large batch of new contacts.
6 Mailercloud actions, graded by risk.
Every Mailercloud action is tagged read, write or destructive, so one policy covers the whole app and new actions inherit the right default.
read
2Look things up. Allowed by default.
- mailercloud.get_client_planGet Client Plan
- mailercloud.search_contactsSearch Contacts in List
write
3Create and change things. Allow, or ask the user first.
- mailercloud.create_listCreate List
- mailercloud.create_propertyCreate custom property
- mailercloud.update_propertyUpdate Contact Property
destructive
1Delete, cancel or archive. Ask first, or deny outright.
- mailercloud.delete_propertyDelete Contact Property
Mailercloud in three steps.
- 01Your users connect MailercloudThey add their Mailercloud api key on Arc0 Connect, under your brand. It goes straight into the vault.
- 02You set the rulesReads run, writes like “create List” can wait for the user, and “delete Contact Property” can be denied outright.
- 03Any agent can actYour agent calls Mailercloud through the Arc0 SDK or MCP, and so can Claude, ChatGPT and Cursor. Every call lands on the audit log.
await arc0.policies.set('mailercloud', { read: 'allow', write: 'ask', // create_list destructive: 'deny', // delete_property }) # Claude Code: the same connection, one URL $ claude mcp add --transport http arc0 \ https://mcp.arc0.ai/u/u_8f2
How Mailercloud connects.
Users add their Mailercloud api key on Arc0 Connect. It is encrypted in the vault, never shown to the model, and each user can rotate or revoke it at any time.
The same Mailercloud connection serves your agent over MCP and your own backend over REST and the proxy, so a user connects once. How Arc0 handles credentials →
- AUTH
- API key
- CREDENTIALS
- Per-tenant encrypted vault
- MODEL SEES
- Results only, never credentials
- AUDIT LOG
- Every call, on every plan
Use Mailercloud from any agent.
ClaudeChatGPTCursor
Codex
VS CodeOpenAI Agents SDKClaude Agent SDK
Vercel AI SDK
Mastra
LangGraph
Mailercloud and Arc0, answered.
Can I use Mailercloud with Claude, ChatGPT or Cursor?
Yes. Connect Mailercloud to Arc0 once, then add your Arc0 MCP URL to Claude, ChatGPT, Cursor, Claude Code or any other remote-MCP client. Each assistant only gets the Mailercloud actions you allow.
How do users connect Mailercloud?
Users add their Mailercloud api key on Arc0 Connect. It is encrypted in the vault, never shown to the model, and each user can rotate or revoke it at any time.
Which Mailercloud actions can my agent take?
6 in total: 2 read, 3 write and 1 destructive, such as “create List”. Your policies decide which of them each agent may call.
Can I stop my agent from deleting things in Mailercloud?
Yes. Actions like “delete Contact Property” are graded destructive. Set destructive actions to deny, or to ask so the user approves each one, and blocked calls still show up on the audit log.
Can my own backend call Mailercloud too?
Yes. The same Mailercloud connection is available over REST and through the Arc0 proxy, so your product and your agent share one connection per user.
Plug Mailercloud into your agent.
Your users connect Mailercloud once, under your brand. Your agent gets 6 actions behind your policies, with every call on the record.
Free to build · MCP + REST · Audit log on every plan