| name | piprail |
| description | A self-custodial crypto payment wallet for your OpenClaw agent, with a hard spend cap it can't exceed. It autonomously pays x402 paywalls ('402 Payment Required') on every major chain, settling funds straight to the recipient — no facilitator, no fee, no signup. Runs read-only with no key (discover/quote/plan before you add a wallet); add a key only to let the agent pay, optionally gaslessly via the standard x402 'exact' rail. |
| metadata | {"openclaw":{"emoji":"🛤️","homepage":"https://piprail.com","os":["darwin","linux","win32"],"requires":{"bins":["npx"]},"install":[{"id":"node","kind":"node","package":"@piprail/mcp","bins":["piprail-mcp"],"label":"Install @piprail/mcp (the PipRail MCP server)"}]}} |
PipRail — Agent Payment Wallet 🛤️
Give your OpenClaw agent a self-custodial crypto payment wallet with a hard spend cap it
can't exceed. It autonomously pays x402 "402 Payment Required" paywalls across every major
chain — settling funds straight to the recipient's wallet, with no facilitator, no fee, no signup.
No API key. No account. No signup. PipRail is self-custodial — you bring a wallet you control.
It even runs read-only with zero config: discover, quote, register, budget, and guide
work the moment it starts, no key at all. Add your own wallet key (PIPRAIL_PRIVATE_KEY) only when
the agent should actually pay — it's a wallet signing key you hold, never an API credential, and
it never leaves your machine.
PipRail plugs into OpenClaw as a standard MCP server — the published
@piprail/mcp (npx -y @piprail/mcp) over stdio —
so the agent gets all 8 tools natively, capped by a budget it can't exceed.
Why PipRail (vs every other crypto skill)
Every other OpenClaw payment skill routes through a facilitator or custodian that holds keys
and/or takes a cut. PipRail is different:
- Backendless — no facilitator, no hosted service. Payments verify locally against your own RPC.
- No fee — funds settle straight to the service provider's wallet. PipRail takes nothing.
- Self-custodial — your key, your machine. PipRail hosts and holds nothing.
- Every major chain — EVM (Base, Ethereum, Polygon, Arbitrum, Optimism, Avalanche, BNB…), Solana,
TON, Tron, NEAR, Sui, Aptos, Algorand, Stellar, XRPL — one
PIPRAIL_CHAIN param picks everything.
- Gasless when you want it — opt into the standard x402
exact rail (PIPRAIL_SCHEMES=exact) and the
agent pays zero gas: it signs the transfer (EIP-3009/Permit2 on EVM, SVM on Solana) and the server settles.
- A hard spend cap the model can't cross —
PIPRAIL_MAX_TOTAL=5.00 and that's the ceiling, enforced
in the SDK before any on-chain send. MIT open source.
The 8 tools your agent gets
| Tool | What it does | Moves money? |
|---|
piprail_discover | Find payable x402 APIs on the open indexes — filter by category/asset/reliability, sort by price or uptime | no |
piprail_quote_payment | Get a URL's price without paying | no |
piprail_plan_payment | Check you can afford it (balance + gas + recipient-ready) | no |
piprail_pay_request | Pay the 402 and return the resource | yes |
piprail_register | List your own x402 API so other agents find it — add a category + tags for findability | no |
piprail_budget | Read remaining spend + time leash | no |
piprail_guide | Read the agent contract (how to quote → plan → pay) | no |
piprail_verify_receipt | Re-verify a payment receipt against the chain, wallet-free | no |
Only piprail_pay_request moves funds. Six tools — discover, quote, register, budget,
guide, verify_receipt — work with no key at all; pay and plan (it reads your balance) need your wallet.
Install
Discover + install on ClawHub (either command works):
clawhub install piprail
openclaw skills install piprail
Then wire the MCP server into ~/.openclaw/openclaw.json — OpenClaw nests servers under mcp.servers.
No key is needed — this is the whole config, and it starts the server read-only
(discover / quote / register / budget / guide all work):
{ "mcp": { "servers": { "piprail": {
"command": "npx", "args": ["-y", "@piprail/mcp"],
"env": { "PIPRAIL_CHAIN": "base" }
} } } }
Want the agent to actually pay? Then — and only then — add your own self-custodial wallet key plus
a budget cap (PIPRAIL_PRIVATE_KEY is a wallet signing key you hold, never an API key):
{ "mcp": { "servers": { "piprail": {
"command": "npx", "args": ["-y", "@piprail/mcp"],
"env": { "PIPRAIL_CHAIN": "base", "PIPRAIL_MAX_TOTAL": "5.00", "PIPRAIL_PRIVATE_KEY": "0xYOUR_KEY" }
} } } }
Restart OpenClaw (or run openclaw mcp set) and the piprail_* tools appear. See Configure below.
Configure
| Variable | Required | Default | Purpose |
|---|
PIPRAIL_PRIVATE_KEY | — (only to pay) | — | Your self-custodial wallet key/seed. Omit it for read-only (discover/quote/register/budget/guide); set it only to let the agent pay. Not an API key; never sent anywhere. |
PIPRAIL_CHAIN | — | base | Which chain to pay on |
PIPRAIL_CHAINS | — | — | Pay across several chains (instead of PIPRAIL_CHAIN) — e.g. base,polygon,solana; give each its own PIPRAIL_<CHAIN>_KEY. The agent pays whichever chain a 402 asks for (the first you listed that can settle), under one shared budget. |
PIPRAIL_MAX_AMOUNT | — | 0.10 | Max per payment, in the token's units (≈ $ for USDC/USDT; native-coin units on a native rail) |
PIPRAIL_MAX_TOTAL | — | 10.00 | Lifetime budget per (chain, token) |
PIPRAIL_TOKENS | — | chain stables | Allowed tokens |
PIPRAIL_SCHEMES | — | onchain-proof | Add exact to also pay standard x402 servers |
PIPRAIL_RPC_URL | — | chain default | Custom RPC endpoint (recommended in production; fold any API key into the URL) |
Defaults are deliberately small and safe (0.10 per payment, 10.00 lifetime, USDC on Base).
Start there, raise as you trust it.
The agent workflow
discover → quote → plan → pay. A typical session:
User: Find me a crypto price API I can pay for.
Agent: [piprail_discover("crypto price")] → cheapest is 0.001 USDC/call on Base.
User: Can I afford it?
Agent: [piprail_plan_payment(url)] → yes; 4.82 USDC left of 5.00, recipient ready, gas ~$0.05.
User: Get me the ETH price.
Agent: [piprail_pay_request(url)] → paid 0.001 USDC (tx 0x…). ETH: $3,247.18. 4.819 USDC left.
Learn more
