Userlist for AI agents
Userlist automates behavior-based email and in-app messaging for SaaS companies, used by product and marketing teams running lifecycle 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 Userlist.
Update a user-company relationship
Sync which company a user belongs to so messaging targets the right account.
Confirm before deleting a company
Check with the user before deleting a company record, since its linked users and history go with it.
Review a company before removal
Look up a company's current data before deciding whether to delete it from Userlist.
2 Userlist actions, graded by risk.
Every Userlist action is tagged read, write or destructive, so one policy covers the whole app and new actions inherit the right default.
read
0Look things up. Allowed by default.
- No read actions.
write
1Create and change things. Allow, or ask the user first.
- userlist.push_relationshipPush User-Company Relationship
destructive
1Delete, cancel or archive. Ask first, or deny outright.
- userlist.delete_companyDelete Company from Userlist
Userlist in three steps.
- 01Your users connect UserlistThey add their Userlist api key on Arc0 Connect, under your brand. It goes straight into the vault.
- 02You set the rulesReads run, writes like “push User-Company Relationship” can wait for the user, and “delete Company from Userlist” can be denied outright.
- 03Any agent can actYour agent calls Userlist through the Arc0 SDK or MCP, and so can Claude, ChatGPT and Cursor. Every call lands on the audit log.
await arc0.policies.set('userlist', { read: 'allow', write: 'ask', // push_relationship destructive: 'deny', // delete_company }) # Claude Code: the same connection, one URL $ claude mcp add --transport http arc0 \ https://mcp.arc0.ai/u/u_8f2
How Userlist connects.
Users add their Userlist 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 Userlist 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 Userlist from any agent.
ClaudeChatGPTCursor
Codex
VS CodeOpenAI Agents SDKClaude Agent SDK
Vercel AI SDK
Mastra
LangGraph
Userlist and Arc0, answered.
Can I use Userlist with Claude, ChatGPT or Cursor?
Yes. Connect Userlist 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 Userlist actions you allow.
How do users connect Userlist?
Users add their Userlist 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 Userlist actions can my agent take?
2 in total: 0 read, 1 write and 1 destructive, such as “push User-Company Relationship”. Your policies decide which of them each agent may call.
Can I stop my agent from deleting things in Userlist?
Yes. Actions like “delete Company from Userlist” 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 Userlist too?
Yes. The same Userlist connection is available over REST and through the Arc0 proxy, so your product and your agent share one connection per user.
Plug Userlist into your agent.
Your users connect Userlist once, under your brand. Your agent gets 2 actions behind your policies, with every call on the record.
Free to build · MCP + REST · Audit log on every plan