# agent-payment [Health: Active] **Category:** πŸ’» Developer Tools **Repository:** https://github.com/evidai/agent-payment-mcp **GitHub Stars:** 3 **Views:** 0 **Installs:** 0 **Upvotes:** 0 **Directory Page:** https://allmcps.com/mcp/agent-payment ## Description USDC micropayments for AI agents. Pay-per-call any HTTP API. Kill switch + spend limits. ## Claude Desktop Quick Installation Install path detected from listing signals. Uses `npx` (confidence: high): ```json "mcpServers": { "agent-payment": { "command": "npx", "args": ["-y","create-lemon-mcp"] } } ``` ## Documentation & README
# πŸ‹ LemonCake **The billing, budget & identity layer for software for agents.** `Private Beta Β· Open core` *Monetize any MCP/API in minutes, and let AI agents pay for it safely β€” each agent gets a spend-capped identity (budget, usage, pause/revoke). Buyers pay by card; **no crypto wallet**.* *First 3,000 calls free (lifetime). Then 3% only when your API earns.* [![License: MIT (SDK)](https://img.shields.io/badge/license-MIT_(SDK)-green.svg)](LICENSE) [![Open core](https://img.shields.io/badge/model-open--core-brightgreen.svg)](#-open-core) [![MCP Compatible](https://img.shields.io/badge/MCP-compatible-blue.svg)](https://modelcontextprotocol.io) [![x402 native](https://img.shields.io/badge/x402-native-blueviolet)](https://x402.org) [![npm: agent-payment-mcp](https://img.shields.io/npm/v/agent-payment-mcp?label=agent-payment-mcp)](https://www.npmjs.com/package/agent-payment-mcp) [![FSA-confirmed](https://img.shields.io/badge/Japan_FSA-registration_not_required-blue)](https://lemoncake.xyz/security) [![Glama score](https://glama.ai/mcp/servers/evidai/lemon-cake/badges/score.svg)](https://glama.ai/mcp/servers/evidai/lemon-cake) **[πŸš€ Get started](#-get-started) Β· [πŸ’² Pricing](https://lemoncake.xyz/pricing) Β· [πŸ“š Docs](https://lemoncake.xyz/docs) Β· [🌐 Live](https://lemoncake.xyz)**
An AI agent pays for paid API calls on its own β€” spend-capped, no crypto ☝️ A real AI agent buys API calls by itself ($0.01 each), stops at its cap, and the API owner earns β€” no human, no crypto. Β· demo source
--- ## πŸš€ Get started **Monetizing an MCP/API? Start here β€” one command:** ```bash npx create-lemon-mcp my-paid-mcp # a paid MCP server, running in sandbox now # then add a Seller Key in /app and set LEMONCAKE_SELLER_KEY β†’ it charges for real (no code change) ``` Pick your path: | I want to… | Do this | |---|---| | **Monetize my MCP/API** (sellers) | **`npx create-lemon-mcp`** β†’ add a Seller Key in [/app](https://lemoncake.xyz/app) to go live | | Add billing to a server I **already have** | [`@lemon-cake/mcp-sdk`](https://www.npmjs.com/package/@lemon-cake/mcp-sdk) β€” wrap a tool with `lc.charge()`, or route through the gateway (no code) | | **Let an agent pay** for paid APIs (buyers) | `npx -y agent-payment-mcp` β€” 8 free demo tools, no signup |
Buyer-side MCP β€” try in 30 seconds ```bash npx -y agent-payment-mcp ``` ```json { "mcpServers": { "lemon": { "command": "npx", "args": ["-y", "agent-payment-mcp"] } } } ``` Ask your agent to run `list_demos` / `call_demo`. To call **paid** APIs, set `LC_PAY_TOKEN` (get one at [lemoncake.xyz/app](https://lemoncake.xyz/app)).
--- ## What is LemonCake? LemonCake is an **x402 payment rail** for monetizing MCP servers and HTTP APIs. Sellers register an endpoint and set a price per call. Buyers prepay by card and receive a spend-capped Pay Token. Agents call the gateway with that token, and LemonCake verifies, meters, forwards, and records usage. ```mermaid sequenceDiagram participant A as πŸ€– AI Agent participant G as πŸ‹ LemonCake Gateway participant API as Your API A->>G: POST /g/:id (no token) G-->>A: 402 + accepts[] (price, mintUrl) A->>G: mint Pay Token (off-session, capped) A->>G: Bearer :jwt G->>API: forward (upstream key hidden) API-->>A: 200 + result Note over A,G: budget exhausted β†’ 402 β†’ agent self-funds β†’ continues ``` **Sellers** register any HTTP API and set a price per call. **Buyers / agents** prepay with a card β†’ Pay Token issued automatically β†’ agent calls the API within budget. Budget exhausted β†’ 402 challenge β†’ agent self-funds β†’ continues. No humans. --- ## 🧱 Open core | Layer | Status | Where | |---|---|---| | Buyer-side MCP (`agent-payment-mcp`) | βœ… MIT | [npm](https://www.npmjs.com/package/agent-payment-mcp), [src](https://github.com/evidai/agent-payment-mcp/blob/HEAD/mcp-server) | | Seller SDK (`@lemon-cake/mcp-sdk`) | βœ… MIT | [npm](https://www.npmjs.com/package/@lemon-cake/mcp-sdk), [src](https://github.com/evidai/agent-payment-mcp/blob/HEAD/lemoncake-mcp-sdk) | | Starter templates | βœ… MIT | [examples/](https://github.com/evidai/agent-payment-mcp/blob/HEAD/examples) | | Docs site | βœ… Public | [lemoncake.xyz/docs](https://lemoncake.xyz/docs) | | **Gateway + billing engine** | πŸ”’ Hosted | lemoncake.xyz | | **Dashboard** (analytics, usage ledger) | πŸ”’ Hosted | lemoncake.xyz/app | --- ## πŸ’³ How payment works ### For buyers (human or agent) 1. Open a **buy link** (`lemoncake.xyz/buy/`) 2. Pay with a card β†’ **Pay Token (JWT) issued automatically** 3. Pass `Authorization: Bearer ` to the gateway 4. Gateway verifies, meters, forwards to the real API 5. Budget exhausted β†’ 402 challenge returned with payment instructions ### For agents (fully autonomous) 1. Issue a **Buyer Key** (`bk_...`) at [/app](https://lemoncake.xyz/app) β†’ Pay Tokens pane 2. Save a card once at [/agent/fund](https://lemoncake.xyz/agent/fund) 3. Agent calls `POST /api/lc/agent/tokens` (Bearer bk_) β†’ off-session card charge β†’ JWT 4. Agent uses JWT to call gateway β€” **hard-capped, no human in the loop** ```json // MCP config for agent with pre-issued Pay Token { "mcpServers": { "lemon": { "command": "npx", "args": ["-y", "agent-payment-mcp"], "env": { "LC_PAY_TOKEN": "" } } } } ``` --- ## πŸ— Publish your API on LemonCake (sellers) Monetize any HTTP API or MCP server: 1. Sign in at [lemoncake.xyz/app](https://lemoncake.xyz/app) 2. **Add API** β€” paste your URL, set price per call (e.g. `$0.01`) 3. Share the **buy link**, or issue a **Seller Key** (`sk_live_…`) to charge from your own server 4. **You keep 97%.** LemonCake takes 3% (Stripe Connect Direct Charge). Never holds funds. **Scaffold a paid MCP in one command** β€” sandbox by default, production with one env var: ```bash npx create-lemon-mcp my-paid-mcp # demo runs with no key # then: set LEMONCAKE_SELLER_KEY=sk_live_… β†’ it charges for real (no code change) ``` Add billing to any tool with the SDK ([`@lemon-cake/mcp-sdk`](https://www.npmjs.com/package/@lemon-cake/mcp-sdk) v1, no crypto): ```typescript import { createLemonCakeSDK } from "@lemon-cake/mcp-sdk"; const lc = createLemonCakeSDK(); // reads LEMONCAKE_SELLER_KEY (demo without it) server.tool("my_premium_tool", "desc", { q: z.string() }, lc.charge({ price: 0.01 })(async ({ q }) => { return { content: [{ type: "text", text: "result" }] }; }), ); ``` `lc.charge` wraps the handler: preflight (reserve) β†’ run β†’ settle (confirm on success, refund on failure). Or route existing traffic through `https://lemoncake.xyz/g/` β€” **no code changes required**. --- ## πŸͺͺ Agent Identity Give each AI agent its own spend-capped identity β€” so a fleet can pay for APIs without a shared card or runaway cost. Built on top of Pay Tokens; **no balance pool, custody-free** (an agent's "budget" is just the Pay Tokens bound to it). - **Bind a Pay Token to an agent** when issuing it (`agentId`) β†’ spend is attributed to that agent. - **Per-agent rollup** β€” budget, spend, calls, last-used in the dashboard. - **Kill switch** β€” `pause` / `resume` / `revoke` an agent; bound tokens are rejected at the gateway instantly (`AGENT_PAUSED` / `AGENT_REVOKED`), even with budget remaining. - **Server-authoritative** β€” price is set on the endpoint; agents never carry a card or a seller key. ```bash # manage agents (owner-authenticated) POST /api/agents # create β†’ { agent_id, ... } POST /api/agents/:id/pause # kill switch (also /resume, /revoke) GET /api/agents # list + per-agent spend rollup ``` --- ## ✨ Features ### For agents / buyers - βœ… **x402 native** β€” 402 challenge returns `accepts[]` with price + mintUrl - βœ… **Hard-capped** β€” per-mint / daily / monthly limits, server-enforced - βœ… **Off-session top-up** β€” agent self-funds via Buyer Key (`bk_...`), no prompts - βœ… **Demo Mode** β€” 8 free tools, try without any setup ### For API providers / sellers - βœ… **5-min go-live** β€” `npx create-lemon-mcp`, or `lc.charge()` on any tool, or route through the gateway - βœ… **Custody-free** β€” Stripe Connect Direct Charge, 97% goes directly to seller - βœ… **Usage ledger** β€” every call recorded, revenue visible in dashboard - βœ… **Buy link** β€” share one URL, buyers self-serve ### For agent fleets / operators - βœ… **Per-agent identity** β€” bind Pay Tokens to an agent, attribute spend - βœ… **Per-agent kill switch** β€” pause / resume / revoke, enforced at the gateway - βœ… **Spend rollup** β€” budget / spent / calls per agent - βœ… **No balance pool** β€” custody-free; budget = the agent's bound Pay Tokens ### Infrastructure - πŸ”§ Stripe Connect Direct Charge (no custody) - πŸ”§ x402 gateway with `WWW-Authenticate: Lemoncake-Prepaid` - πŸ”§ EN / ζ—₯本θͺž / EspaΓ±ol dashboard - πŸ”§ [JP FSA: registration not required](https://lemoncake.xyz/security) (confirmed 2026-06) --- ## πŸ— Architecture ``` β”Œβ”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β” β”‚ Buyer / Agent β”‚ β”‚ ↳ prepays via card OR Buyer Key (bk_...) β”‚ β”‚ ↳ receives Pay Token (signed JWT) β”‚ β””β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”¬β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”˜ β”‚ Authorization: Bearer β–Ό β”Œβ”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β” β”‚ LemonCake Gateway /g/ β”‚ β”‚ ↳ verify JWT signature β”‚ β”‚ ↳ check budget + calls + rate limit β”‚ β”‚ ↳ decrement spend, write to ledger β”‚ β””β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”¬β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”˜ β”‚ HTTPS + upstream_auth (hidden) β–Ό β”Œβ”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β” β”‚ Your API / MCP server (unchanged) β”‚ β””β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”˜ ``` LemonCake is the middle box. It never holds funds β€” money flows Stripe β†’ seller via Direct Charge. --- ## 🌍 Compliance Japan FSA Fintech Support Desk (2026-06) confirmed: no registration required. Custody-free design (Stripe Connect Direct Charge, no pooled balance). | Jurisdiction | Basis | |---|---| | πŸ‡―πŸ‡΅ Japan | FSA β€” registration not required | | πŸ‡ΊπŸ‡Έ USA | FinCEN 2019 Β§4.5 β€” non-custodial software β‰  MSB | | πŸ‡ͺπŸ‡Ί EU | MiCA β€” non-CASP | | πŸ‡¬πŸ‡§ UK | FCA β€” Tech Service Provider | | πŸ‡ΈπŸ‡¬ Singapore | MAS β€” DPT non-applicable | | πŸ‡¨πŸ‡¦ Canada | FINTRAC β€” non-custodial exemption | | πŸ‡¨πŸ‡­ Switzerland | FINMA β€” non-financial intermediary | See [lemoncake.xyz/security](https://lemoncake.xyz/security) --- ## πŸ”Œ Package family | Package | What it does | |---|---| | [`agent-payment-mcp`](https://www.npmjs.com/package/agent-payment-mcp) | Main entry β€” x402 gateway + agent payment rail | | [`@lemon-cake/mcp-sdk`](https://www.npmjs.com/package/@lemon-cake/mcp-sdk) | Seller SDK β€” `lc.charge()` / `lc.protect()`, fiat, no crypto | | [`create-lemon-mcp`](https://www.npmjs.com/package/create-lemon-mcp) | Scaffold a paid MCP server β€” sandboxβ†’prod with one env var | | [`xstocks-mcp`](https://www.npmjs.com/package/xstocks-mcp) | Buy tokenized US stocks on Solana | | [`alpaca-guard-mcp`](https://www.npmjs.com/package/alpaca-guard-mcp) | Alpaca paper / live trading with hard daily cap | | [`tokenized-stock-mcp`](https://www.npmjs.com/package/tokenized-stock-mcp) | Dinari dShares | --- ## πŸ›‘ Security - **Server-side hard caps** β€” per-mint / daily / monthly, cannot be exceeded - **Pay Token = signed JWT** β€” HS256, verified on every gateway call - **upstream_auth never exposed** β€” seller's real API key hidden from buyers - **RLS on all DB tables** β€” Supabase row-level security enabled - **Stripe Connect Direct Charge** β€” LemonCake never holds funds