Agenticpay MCP Server

agenticpay

Get paid by AI agents. Open-source payment infrastructure for the MCP ecosystem — declare a price on any tool, agents pay in USDC over x402, settles on Solana in ~1.5 seconds.

No Stripe. No accounts. No API keys.

The full stack is here — SDK, CLI, paywall middleware, self-hosted x402 facilitator, and a live LLM agent demo. All TypeScript, MIT licensed.

Just want to test it? Point your mcp-server at our hosted devnet facilitator: FACILITATOR_URL=https://agentpay-facilitator-e9b20a5fee6a.herokuapp.com — no setup needed.

Live demo

A real Claude Opus agent receives a task, decides which paid tools to use, pays autonomously via x402 micropayments on Solana, and answers the user.

$ pnpm --filter @agenticpay/two-agent-demo agent

Agent wallet: 3rHoEumCpH8EGrr6Lq2vBKeyec6h3yPRGj2nGG2FzEfX
Server:       http://localhost:4021
Facilitator:  http://localhost:4022   ← our own
Model:        claude-opus-4-7
Task:         Reverse the string 'agentpay rocks' and tell me how many words
              are in 'The quick brown fox jumps over the lazy dog'.

[turn 1] tool_use: reverse_string({"text":"agenticpay rocks"})  →  paying $0.001 USDC ...
  ✓ paid + got result in 1596ms: {"result":"skcor yaptnega"}
[turn 1] tool_use: word_count({"text":"The quick..."})  →  paying $0.0005 USDC ...
  ✓ paid + got result in 1286ms: {"count":9}

Agent final answer:
  1. Reversed string: skcor yaptnega
  2. Word count: 9 words

=== payments summary ===
  reverse_string   $0.0010 USDC   1596ms
  word_count       $0.0005 USDC   1286ms
  TOTAL            $0.0015 USDC   2 calls

On-chain proof (Solana devnet):

• Settled by our self-hosted facilitator: EsqzTG8id...Bnku
• Earlier settle via x402.org: 2d2HcefgJ...vkqY

Why

The current AI agent stack assumes humans hold the credit card. That breaks the moment agents act on their own initiative — calling APIs, hiring sub-agents, paying for compute. You can't OAuth your way through it.

Stablecoin micropayments over HTTP fix it. agenticpay packages the missing ergonomics for the MCP ecosystem specifically: any tool can declare a price, any agent can pay it, and the whole pipeline — including the facilitator that actually submits the on-chain settlement — is open source and self-hostable.

Architecture

┌──────────────┐     1) HTTP request                    ┌─────────────┐
│   Claude /   │ ────────────────────────────────────▶ │  mcp-server │
│   GPT agent  │     2) HTTP 402 + payment requirements │  (yours)    │
│              │ ◀──────────────────────────────────── │             │
│              │     3) signed USDC payload             │             │
│              │ ────────────────────────────────────▶ │             │
└──────────────┘                                        └─────┬───────┘
                                                              │ verify+settle
                                                              ▼
                                                   ┌──────────────────────┐
                                                   │ agenticpay facilitator │
                                                   │   (also yours, this  │
                                                   │    repo, port 4022)  │
                                                   └──────────┬───────────┘
                                                              │ submit
                                                              ▼
                                                          Solana
                                                       (USDC SPL,
                                                       sub-cent fees)

You can also point mcp-server at the public x402.org/facilitator for testnet/devnet, or at Coinbase CDP for mainnet. We just made the self-hosted route easy.

Packages

Install

npm install @agenticpay/sdk           # Solana + USDC primitives
npm install -g @agenticpay/cli        # `agenticpay` command
npm install @agenticpay/mcp-server    # paywalled HTTP server
npm install @agenticpay/facilitator   # self-hosted x402 facilitator
npm install @agenticpay/eliza-plugin  # Eliza plugin (Solana-native agents)
npm install @agenticpay/ai-sdk        # Vercel AI SDK paid tools
npm install -g @agenticpay/mcp-bridge # MCP server for Claude Desktop / Cursor

Or clone the monorepo to get the live two-agent demo and edit-friendly templates (recommended for first run — see Quickstart below).

Use with Claude Code

This repo ships an Anthropic Skill at .claude/skills/agenticpay/SKILL.md. Copy it into your ~/.claude/skills/ to give Claude Code first-class context about agenticpay — it'll then walk you through monetizing an MCP server, generating tool routes, and verifying on-chain settlements without re-reading the README every time.

mkdir -p ~/.claude/skills
cp -r .claude/skills/agenticpay ~/.claude/skills/

Quickstart (devnet, ~5 minutes, free)

# 1. Install
pnpm install
pnpm -r build

# 2. Generate a payer wallet, fund it on devnet
node packages/cli/dist/index.js wallet new
node packages/cli/dist/index.js wallet show
# → fund SOL at https://faucet.solana.com  (paste pubkey)
# → fund USDC at https://faucet.circle.com (Solana Devnet, same pubkey)

# 3. (option A — fastest) Use our hosted devnet facilitator. Skip step 4.
export FACILITATOR_URL=https://agentpay-facilitator-e9b20a5fee6a.herokuapp.com

# 3. (option B — fully self-hosted) Start your own facilitator (terminal 1)
pnpm --filter @agenticpay/facilitator dev
# Note the printed feePayer address. It needs ~0.05 SOL devnet to cover fees.
# Either airdrop or use the helper:
pnpm --filter @agenticpay/facilitator fund
export FACILITATOR_URL=http://localhost:4022

# 4. Start the paywalled mcp-server (terminal 2)
PAY_TO=<recipient pubkey> pnpm --filter @agenticpay/mcp-server dev

# 5. Run the live LLM agent demo (terminal 3, needs ANTHROPIC_API_KEY in .env)
pnpm --filter @agenticpay/two-agent-demo agent

Framework integrations

Drop-in templates for the most common AI agent stacks live under examples/:

See examples/README.md for the integration matrix.

Status

Pre-alpha. Devnet validated end-to-end. Mainnet config supported but requires funding the facilitator with real SOL and pointing at a mainnet-capable RPC (Helius, QuickNode, etc.).

Roadmap

• Devnet end-to-end demo (smoke + LLM agent)
• Self-hosted x402 facilitator (verify + settle, fee_payer abstraction)
• Real-world MCP server template (search, fetch, summarize, extract — instead of toy reverse_string)
• On-chain escrow for long-running tasks (Anchor program)
• Agent reputation registry on-chain
• Hosted facilitator service (agenticpay.com)

What's a facilitator?

If you've never seen x402 before: the facilitator is the trusted middleman that (1) verifies an agent's signed payment payload, (2) submits the USDC transfer on-chain, and (3) pays the SOL gas fees so the agent doesn't need any SOL — only USDC. Most MCP devs don't want to run their own; they point at a hosted one.

This repo ships a complete facilitator implementation. You can self-host it, fork it, audit it, or deploy it as a service for your own users.

What happens when a paid tool call fails?

Short version: a failed tool call is never charged. x402 settlement is an irreversible push, so the middleware is careful about when it settles:

1. Verify before execute. The payment payload (signature, funds, requirements match) is verified before your tool handler runs. Invalid payment → HTTP 402, the tool never executes.
2. Execute with a buffered response. The handler runs, but its response is held back — nothing is sent to the agent yet.
3. Settle only on success. If the handler responds with status ≥ 400, the middleware skips settlement entirely and just returns the error. The agent pays nothing for a failed call.
4. No result without payment. If on-chain settlement itself fails, the buffered tool result is discarded and the agent gets a payment error instead — the server never leaks a result it wasn't paid for.

What this doesn't cover: a tool that returns 200 OK with a junk answer is still charged — the protocol can't judge response quality. That's what keeps per-call prices micro ($0.0005–$0.001 in the demo): the worst case is capped at one call's price, and quality enforcement belongs to a reputation layer (see Roadmap) rather than the payment protocol.

License

MIT