Moonclerk for AI agents
MoonClerk lets small businesses accept recurring and one-time online payments through hosted, no-code payment forms without building custom checkout pages. 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 Moonclerk.
Look up a customer's subscription
Check a customer's active subscription and payment history to answer a billing question, read-only.
Check a payment form's submissions
List payments received through a specific form to reconcile revenue against what was expected for the period.
Review active discounts
List discounts currently configured on payment forms before applying one to a new offer.
5 Moonclerk actions, graded by risk.
Every Moonclerk 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.
- moonclerk.list_formsList Payment Forms
- moonclerk.list_paymentsList Payments
- moonclerk.list_customersList Customers
- moonclerk.list_discountsList Discounts
- moonclerk.list_subscriptionsList Subscriptions
write
0Create and change things. Allow, or ask the user first.
- No write actions.
destructive
0Delete, cancel or archive. Ask first, or deny outright.
- No destructive actions.
Moonclerk in three steps.
- 01Your users connect MoonclerkThey add their Moonclerk api key on Arc0 Connect, under your brand. It goes straight into the vault.
- 02You set the rulesReads run, and writes like “updates” can wait for the user to approve.
- 03Any agent can actYour agent calls Moonclerk through the Arc0 SDK or MCP, and so can Claude, ChatGPT and Cursor. Every call lands on the audit log.
await arc0.policies.set('moonclerk', { read: 'allow', write: 'ask', destructive: 'deny', }) # Claude Code: the same connection, one URL $ claude mcp add --transport http arc0 \ https://mcp.arc0.ai/u/u_8f2
How Moonclerk connects.
Users add their Moonclerk 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 Moonclerk 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 Moonclerk from any agent.
ClaudeChatGPTCursor
Codex
VS CodeOpenAI Agents SDKClaude Agent SDK
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LangGraphMore finance and accounting apps.
Moonclerk and Arc0, answered.
Can I use Moonclerk with Claude, ChatGPT or Cursor?
Yes. Connect Moonclerk 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 Moonclerk actions you allow.
How do users connect Moonclerk?
Users add their Moonclerk 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 Moonclerk actions can my agent take?
5 in total: 5 read, 0 write and 0 destructive. Your policies decide which of them each agent may call.
Can I make my agent read-only in Moonclerk?
Yes. Allow read actions and deny writes in the Moonclerk policy. Your agent can still look things up, and any write it attempts is blocked and logged.
Can my own backend call Moonclerk too?
Yes. The same Moonclerk connection is available over REST and through the Arc0 proxy, so your product and your agent share one connection per user.
Plug Moonclerk into your agent.
Your users connect Moonclerk once, under your brand. Your agent gets 5 actions behind your policies, with every call on the record.
Free to build · MCP + REST · Audit log on every plan