Sender for AI agents
Sender is an email marketing platform for building campaigns, automated workflows, and subscriber lists, aimed at small businesses and independent creators on a budget. 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 Sender.
Create or update a subscriber
Adds a new subscriber or updates their tags and custom fields inside a subscriber list.
Look up a campaign's details
Reads a specific campaign's status and content before deciding whether to reuse or edit it.
Update subscriber fields only after approval
Changes a subscriber's custom fields only once the update has been confirmed by the marketing team.
8 Sender actions, graded by risk.
Every Sender action is tagged read, write or destructive, so one policy covers the whole app and new actions inherit the right default.
read
5Look things up. Allowed by default.
- sender.get_all_fieldsGet All Fields
- sender.get_group_by_idGet Group By ID
- sender.get_all_workflowsGet All Workflows
- sender.get_campaign_by_idGet Campaign By ID
- sender.get_subscriber_by_idGet Subscriber By ID
write
3Create and change things. Allow, or ask the user first.
- sender.create_fieldCreate Field
- sender.update_subscriber_fieldsUpdate Subscriber Fields
- sender.create_or_update_subscriberCreate Or Update Subscriber
destructive
0Delete, cancel or archive. Ask first, or deny outright.
- No destructive actions.
Sender in three steps.
- 01Your users connect SenderThey add their Sender api key on Arc0 Connect, under your brand. It goes straight into the vault.
- 02You set the rulesReads run, and writes like “create Field” can wait for the user to approve.
- 03Any agent can actYour agent calls Sender through the Arc0 SDK or MCP, and so can Claude, ChatGPT and Cursor. Every call lands on the audit log.
await arc0.policies.set('sender', { read: 'allow', write: 'ask', // create_field destructive: 'deny', }) # Claude Code: the same connection, one URL $ claude mcp add --transport http arc0 \ https://mcp.arc0.ai/u/u_8f2
How Sender connects.
Users add their Sender 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 Sender 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 Sender from any agent.
ClaudeChatGPTCursor
Codex
VS CodeOpenAI Agents SDKClaude Agent SDK
Vercel AI SDK
Mastra
LangGraph
Sender and Arc0, answered.
Can I use Sender with Claude, ChatGPT or Cursor?
Yes. Connect Sender 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 Sender actions you allow.
How do users connect Sender?
Users add their Sender 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 Sender actions can my agent take?
8 in total: 5 read, 3 write and 0 destructive, such as “create Field”. Your policies decide which of them each agent may call.
Can I make my agent read-only in Sender?
Yes. Allow read actions and deny writes in the Sender policy. Your agent can still look things up, and any write it attempts is blocked and logged.
Can my own backend call Sender too?
Yes. The same Sender connection is available over REST and through the Arc0 proxy, so your product and your agent share one connection per user.
Plug Sender into your agent.
Your users connect Sender once, under your brand. Your agent gets 8 actions behind your policies, with every call on the record.
Free to build · MCP + REST · Audit log on every plan