How do I install the Taiko X402 skill?

Run npx skillmds@latest add taikoxyz/taiko-x402 in your terminal (requires Node.js), paste this page's agent-chat prompt into Claude, Cursor, or any MCP-connected agent, or download the SKILL.md file and copy it into your agent's skills directory.

Is Taiko X402 safe to use?

This skill has not completed SkillMD's automated safety review yet. SkillMD never runs a skill's scripts for you; review the SKILL.md before installing.

Which AI agents work with Taiko X402?

This skill is tagged as working with Claude Code, Claude.ai, OpenAI Codex. SKILL.md is an open format, so most agents that read a skills directory can load it too.

Is Taiko X402 free to use?

Yes. Installing skills from SkillMD is free, and the skill stays under its author's original license.

Who published Taiko X402?

taikoxyz (@taikoxyz) published this skill. Their other Agent Skills are listed on their SkillMD profile.

Taiko X402 by taikoxyz — Agent Skill

Name: Taiko X402
Author: taikoxyz

Taiko X402

Build and integrate x402 HTTP payment flows on Taiko using Taiko-operated facilitators. Use when adding per-request USDC payment gating to APIs deployed on Taiko (seller), building AI agents or clients that autonomously pay for x402 services (buyer), or configuring Taiko facilitators. Triggers: "x402", "HTTP payment", "pay per request", "monetize API", "USDC payment", "402 Payment Required", "facilitator.taiko.xyz", "paid API", "AI agent payments", "payment middleware".

taikoxyz b2fc30d 4 files · 15.4 KB Updated Sep 17, 2026

File contents

x402 Payments on Taiko

Network Selection: If the user has not specified "hoodi" or "mainnet", always ask which network to use before proceeding.

x402 is an open HTTP payment protocol: a server responds 402 Payment Required with a price; a client signs an EIP-712 USDC authorization and retries. No accounts, sessions, or subscriptions needed — payment is the authentication.

Taiko runs two live facilitators that verify and settle payments on Taiko Mainnet and Hoodi testnet. These handle EIP-3009 signature verification and on-chain USDC transfer on behalf of the buyer.

Lifecycle

Buyer → GET /api → 402 (PAYMENT-REQUIRED header) → sign EIP-712 →
  retry with PAYMENT-SIGNATURE → Facilitator verifies → 200 OK

Quick Decision

Task	What to do
Protect an API endpoint	Seller (server) setup
Call a paid API from code	Buyer (client) setup
Facilitator URLs, CAIP-2 IDs, USDC addresses	Facilitators reference
Both sides (full-stack demo)	Start with server.md, then client.md

Networks

Network	CAIP-2	Facilitator
Taiko Mainnet	`eip155:167000`	`https://facilitator.taiko.xyz`, `https://x402.taiko.xyz`
Taiko Hoodi	`eip155:167013`	`https://facilitator.taiko.xyz` only

No CDP API key required — Taiko facilitators are independent of Coinbase's CDP.

Common Errors

Error	Fix
`No scheme registered for network`	Register the EVM scheme for `eip155:167000` or `eip155:167013`
`Payment already attempted`	Facilitator rejected payment — check USDC balance and allowance
`Invalid signature`	Signer address doesn't match `from` in EIP-712 payload
`Token not supported`	Use the USDC contract address listed in facilitators reference
402 on every request	Middleware misconfigured — check route pattern and `payTo` address
`No default asset configured for network`	Use `price` as `{ amount, asset }` with the verified USDC token address for that Taiko network

Network Contract Addresses

USDC addresses and chain IDs are maintained in the taiko skill:

taiko/references/networks.md — USDC contract addresses per network, chain IDs for CAIP-2 identifiers

Use taiko network info --json to retrieve current contract addresses programmatically:

taiko network info --json --network hoodi    # chain ID, USDC address, explorer URLs
taiko network info --json --network mainnet

MCP Tools for Verification

Task	Tool
Verify USDC contract	`get_contract_abi` — confirm it's the USDC contract before integration
Check buyer USDC balance	`read_contract` — call `balanceOf(address)` on USDC
Debug payment failure	`decode_calldata` — decode payment tx input
Verify payment on-chain	`get_transaction_info` — confirm 402 payment tx hash
Look up facilitator address	`search` — find by name on the target network
Fee guidance	`get_gas_price` — help users estimate appropriate payment amounts

Related Skills

Contract addresses & chain IDs: taiko skill
Foundry & contract deployment: taiko/references/foundry-guide.md

References

Server setup — Express/Next.js/Hono middleware, route config, Bazaar discovery
Client setup — fetch/axios wrappers, wallet signer, USDC requirements
Facilitators — Taiko facilitator URLs, USDC addresses, CAIP-2 identifiers

---name: taiko-x402description: Build and integrate x402 HTTP payment flows on Taiko using Taiko-operated facilitators. Use when adding per-request USDC payment gating to APIs deployed on Taiko (seller), building AI agents or clients that autonomously pay for x402 services (buyer), or configuring Taiko facilitators. Triggers: "x402", "HTTP payment", "pay per request", "monetize API", "USDC payment", "402 Payment Required", "facilitator.taiko.xyz", "paid API", "AI agent payments", "payment middleware".---# x402 Payments on Taiko> **Network Selection:** If the user has not specified "hoodi" or "mainnet", always ask which network to use before proceeding.x402 is an open HTTP payment protocol: a server responds `402 Payment Required` with a price; a client signs an EIP-712 USDC authorization and retries. No accounts, sessions, or subscriptions needed — payment is the authentication.**Taiko runs two live facilitators** that verify and settle payments on Taiko Mainnet and Hoodi testnet. These handle EIP-3009 signature verification and on-chain USDC transfer on behalf of the buyer.## Lifecycle```Buyer → GET /api → 402 (PAYMENT-REQUIRED header) → sign EIP-712 → retry with PAYMENT-SIGNATURE → Facilitator verifies → 200 OK```## Quick Decision| Task | What to do ||------|------------|| Protect an API endpoint | [Seller (server) setup](./references/server.md) || Call a paid API from code | [Buyer (client) setup](./references/client.md) || Facilitator URLs, CAIP-2 IDs, USDC addresses | [Facilitators reference](./references/facilitators.md) || Both sides (full-stack demo) | Start with server.md, then client.md |## Networks| Network | CAIP-2 | Facilitator ||---------|--------|-------------|| Taiko Mainnet | `eip155:167000` | `https://facilitator.taiko.xyz`, `https://x402.taiko.xyz` || Taiko Hoodi | `eip155:167013` | `https://facilitator.taiko.xyz` only |No CDP API key required — Taiko facilitators are independent of Coinbase's CDP.## Common Errors| Error | Fix ||-------|-----|| `No scheme registered for network` | Register the EVM scheme for `eip155:167000` or `eip155:167013` || `Payment already attempted` | Facilitator rejected payment — check USDC balance and allowance || `Invalid signature` | Signer address doesn't match `from` in EIP-712 payload || `Token not supported` | Use the USDC contract address listed in [facilitators reference](./references/facilitators.md) || 402 on every request | Middleware misconfigured — check route pattern and `payTo` address || `No default asset configured for network` | Use `price` as `{ amount, asset }` with the verified USDC token address for that Taiko network |## Network Contract AddressesUSDC addresses and chain IDs are maintained in the taiko skill:- **[taiko/references/networks.md](../taiko/references/networks.md)** — USDC contract addresses per network, chain IDs for CAIP-2 identifiersUse `taiko network info --json` to retrieve current contract addresses programmatically:```bashtaiko network info --json --network hoodi # chain ID, USDC address, explorer URLstaiko network info --json --network mainnet```## MCP Tools for Verification| Task | Tool ||------|------|| Verify USDC contract | `get_contract_abi` — confirm it's the USDC contract before integration || Check buyer USDC balance | `read_contract` — call `balanceOf(address)` on USDC || Debug payment failure | `decode_calldata` — decode payment tx input || Verify payment on-chain | `get_transaction_info` — confirm 402 payment tx hash || Look up facilitator address | `search` — find by name on the target network || Fee guidance | `get_gas_price` — help users estimate appropriate payment amounts |## Related Skills- **Contract addresses & chain IDs:** [taiko skill](../taiko/SKILL.md)- **Foundry & contract deployment:** [taiko/references/foundry-guide.md](../taiko/references/foundry-guide.md)## References- [Server setup](./references/server.md) — Express/Next.js/Hono middleware, route config, Bazaar discovery- [Client setup](./references/client.md) — fetch/axios wrappers, wallet signer, USDC requirements- [Facilitators](./references/facilitators.md) — Taiko facilitator URLs, USDC addresses, CAIP-2 identifiers

Frequently asked questions