Msg91 for AI agents
MSG91 is a cloud communication platform for sending SMS, WhatsApp, email, and voice messages, including OTP verification for logins and transactions. 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 Msg91.
Send an OTP to a user
Send a one-time password to a phone number as part of a login or verification flow.
Verify a submitted OTP
Check a user-entered OTP against the one that was sent, a read-only verification with no side effects.
Approve before a bulk campaign send
Require approval before sending a bulk SMS campaign, since it reaches every recipient at once.
8 Msg91 actions, graded by risk.
Every Msg91 action is tagged read, write or destructive, so one policy covers the whole app and new actions inherit the right default.
read
4Look things up. Allowed by default.
- msg91.list_campaignsList Campaigns
- msg91.get_event_typesGet Event Types
- msg91.get_failed_eventsGet Failed Events
- msg91.verify_otpVerify OTP
write
4Create and change things. Allow, or ask the user first.
- msg91.send_otpSend OTP
- msg91.send_sms_v5Send SMS via Flow (V5)
- msg91.create_user_eventsCreate User Events
- msg91.resend_otpResend OTP
destructive
0Delete, cancel or archive. Ask first, or deny outright.
- No destructive actions.
Msg91 in three steps.
- 01Your users connect Msg91They add their Msg91 api key on Arc0 Connect, under your brand. It goes straight into the vault.
- 02You set the rulesReads run, and writes like “create User Events” can wait for the user to approve.
- 03Any agent can actYour agent calls Msg91 through the Arc0 SDK or MCP, and so can Claude, ChatGPT and Cursor. Every call lands on the audit log.
await arc0.policies.set('msg91', { read: 'allow', write: 'ask', // create_user_events destructive: 'deny', }) # Claude Code: the same connection, one URL $ claude mcp add --transport http arc0 \ https://mcp.arc0.ai/u/u_8f2
How Msg91 connects.
Users add their Msg91 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 Msg91 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 Msg91 from any agent.
ClaudeChatGPTCursor
Codex
VS CodeOpenAI Agents SDKClaude Agent SDK
Vercel AI SDK
Mastra
LangGraph
Msg91 and Arc0, answered.
Can I use Msg91 with Claude, ChatGPT or Cursor?
Yes. Connect Msg91 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 Msg91 actions you allow.
How do users connect Msg91?
Users add their Msg91 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 Msg91 actions can my agent take?
8 in total: 4 read, 4 write and 0 destructive, such as “create User Events”. Your policies decide which of them each agent may call.
Can I make my agent read-only in Msg91?
Yes. Allow read actions and deny writes in the Msg91 policy. Your agent can still look things up, and any write it attempts is blocked and logged.
Can my own backend call Msg91 too?
Yes. The same Msg91 connection is available over REST and through the Arc0 proxy, so your product and your agent share one connection per user.
Plug Msg91 into your agent.
Your users connect Msg91 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