Tollkit SMS
Pay-per-call SMS for AI agents. x402 V2 + AP2 mandates on Arbitrum. Buyers fund one Intent Mandate, agents send N transactional SMS off-chain, we batch-settle every 5 sends. Twilio toll-free verified, TCPA compliant. Part of tollkit.dev.
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描述
TOLLKIT SMS
Pay-per-call SMS for AI agents. Production-grade SMS gateway that lets agents send transactional messages to US recipients—order updates, system alerts, security notifications, account messages—without API keys, contracts, or monthly subscriptions. Settlement happens on-chain in USDC via x402, with multi-chain support across Arbitrum One and Base.
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THE PROBLEM
Per-call x402 payments break at sub-cent scale because settlement gas can exceed payment value. AI agents performing thousands of API calls need settlement economics that supports sub-cent payments—without a separate on-chain transaction every time.
THE SOLUTION
Tollkit SMS combines x402 V2 with AP2 mandates to give agents a pre-funded balance model alongside per-call payments.
1. User signs an Intent Mandate (EIP-712) authorizing the agent to send up to N SMS to their phone over a time window, paid from a specific wallet.
2. Agent calls /send with mandate reference. Seller verifies the signature, debits an off-chain balance ledger, dispatches the SMS.
3. Every 5 sends, the seller batches accumulated debits into one on-chain x402 settlement to Arbitrum.
Result: 50 SMS = 1-2 on-chain transactions. Per-call gas approaches zero. Sub-cent pricing becomes viable.
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KEY FEATURES
- Dual-mode payment — per-call x402 V2 or AP2 Mandate.
- Multi-chain settlement — Arbitrum One and Base via CAIP-2 network IDs.
- TCPA and CTIA compliant — Twilio toll-free verified, STOP/HELP handling, S.H.A.F.T.-C excluded, E.164 US-only.
- Consumer-facing /optin form with EIP-712 mandate signing.
- Per-buyer rate limiting (10/min, 60/hour, 200/day) prevents abuse before payment is signed.
- Cryptographic audit trail linking mandate, Twilio SID, and settlement tx hash.
- Drop-in MCP client on npm: npx -y x402-sms-mcp installs in Claude Desktop, Cursor, Windsurf.
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LIVE LINKS
▸ sms.tollkit.dev — production SMS service
▸ tollkit.dev — umbrella brand and landing page
▸ github.com/UltraStarz/tollkit-mandate-flow — buildathon deliverables
▸ npmjs.com/package/x402-sms-mcp — open-source MCP client
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VISION
Tollkit SMS is the first product in the tollkit.dev family—paid developer tools for AI agents, settling in USDC over x402. Future tools follow the same dual-mode pattern (per-call plus mandate) under one umbrella brand. The mandate primitive enables ecosystem-wide composability: agents can pre-fund balances across multiple paid services without dozens of individual on-chain transactions.