Connect your AI agent to x402
Give any open-source AI coding harness — Claude Code, Codex CLI, Goose, Hermes, IronClaw and more — the ability to pay grug402's x402 endpoints on the Radius testnet. Generate a portable x402-pay SKILL.md, an MCP server config, or an ACP job.
How to connect your AI agent to x402
- Pick your harness and read where its testnet wallet key goes.
- Generate a portable x402-pay SKILL.md with the live facilitator URL, SBC asset, 6 decimals, and scenario URL filled in.
- Install the SKILL.md into your harness's skills directory, or add grug402 as an MCP server or ACP job.
- Fund a testnet wallet with SBC from the faucet and verify the compliant-get scenario.
Per-harness guides
Connect Claude Code to x402
To make Claude Code pay an x402 endpoint on the Radius testnet, drop the generated x402-pay SKILL.md into its skills directory (.claude/skills/x402-pay/SKILL.md). Point it at a grug402 scenario URL; it reads the 402 PAYMENT-REQUIRED challenge, signs a permit2/EIP-712 authorization with a testnet wallet, and retries with PAYMENT-SIGNATURE. Put the testnet wallet key in a shell env var or the project .env — keep .env out of git.
Connect Codex CLI to x402
To make Codex CLI pay an x402 endpoint on the Radius testnet, drop the generated x402-pay SKILL.md into its skills directory (.codex/skills/x402-pay/SKILL.md). Point it at a grug402 scenario URL; it reads the 402 PAYMENT-REQUIRED challenge, signs a permit2/EIP-712 authorization with a testnet wallet, and retries with PAYMENT-SIGNATURE. Store the key in a shell env var; Codex reads it at runtime — never commit it.
Connect Hermes to x402
To make Hermes pay an x402 endpoint on the Radius testnet, drop the generated x402-pay SKILL.md into its skills directory (~/.hermes/skills/x402-pay/SKILL.md). Point it at a grug402 scenario URL; it reads the 402 PAYMENT-REQUIRED challenge, signs a permit2/EIP-712 authorization with a testnet wallet, and retries with PAYMENT-SIGNATURE. Use the Hermes env/secret store. Tirith blocks `curl | sh`, so install from the signed script rather than a piped installer.
Connect IronClaw to x402
To make IronClaw pay an x402 endpoint on the Radius testnet, delegate an ACP job that runs the x402-pay skill (WASM tool + .ironclaw/skills/x402-pay/SKILL.md). Point it at a grug402 scenario URL; it reads the 402 PAYMENT-REQUIRED challenge, signs a permit2/EIP-712 authorization with a testnet wallet, and retries with PAYMENT-SIGNATURE. The key lives in IronClaw's encrypted vault and is injected at the host boundary — the model never sees it.
Connect OpenClaw to x402
To make OpenClaw pay an x402 endpoint on the Radius testnet, drop the generated x402-pay SKILL.md into its skills directory (.claw/skills/x402-pay/SKILL.md). Point it at a grug402 scenario URL; it reads the 402 PAYMENT-REQUIRED challenge, signs a permit2/EIP-712 authorization with a testnet wallet, and retries with PAYMENT-SIGNATURE. Keep the key in the claw secret store / vault, not a plaintext env var.
Connect Goose to x402
To make Goose pay an x402 endpoint on the Radius testnet, add grug402 as an MCP server (~/.config/goose/recipes/x402-pay.yaml). Point it at a grug402 scenario URL; it reads the 402 PAYMENT-REQUIRED challenge, signs a permit2/EIP-712 authorization with a testnet wallet, and retries with PAYMENT-SIGNATURE. Store the key in the Goose keychain / configured secret and reference it from the recipe.
Connect Pi to x402
To make Pi pay an x402 endpoint on the Radius testnet, drop the generated x402-pay SKILL.md into its skills directory (~/.pi/skills/x402-pay/SKILL.md). Point it at a grug402 scenario URL; it reads the 402 PAYMENT-REQUIRED challenge, signs a permit2/EIP-712 authorization with a testnet wallet, and retries with PAYMENT-SIGNATURE. Use an env var or Pi's secret store; never inline the key.
Connect OpenCode to x402
To make OpenCode pay an x402 endpoint on the Radius testnet, drop the generated x402-pay SKILL.md into its skills directory (.opencode/skills/x402-pay/SKILL.md). Point it at a grug402 scenario URL; it reads the 402 PAYMENT-REQUIRED challenge, signs a permit2/EIP-712 authorization with a testnet wallet, and retries with PAYMENT-SIGNATURE. Store the key in a shell env var or a .env kept out of git.
Connect Generic (MCP + SKILL.md) to x402
To make Generic (MCP + SKILL.md) pay an x402 endpoint on the Radius testnet, drop the generated x402-pay SKILL.md into its skills directory (<your-agent>/skills/x402-pay/SKILL.md). Point it at a grug402 scenario URL; it reads the 402 PAYMENT-REQUIRED challenge, signs a permit2/EIP-712 authorization with a testnet wallet, and retries with PAYMENT-SIGNATURE. Provide the testnet wallet key via an environment variable or your agent's secret store — never inline it in the SKILL.md and never commit it.
Frequently asked questions
How do I make Claude Code pay an x402 endpoint? To make Claude Code pay an x402 endpoint on the Radius testnet, drop the generated x402-pay SKILL.md into its skills directory (.claude/skills/x402-pay/SKILL.md). Point it at a grug402 scenario URL; it reads the 402 PAYMENT-REQUIRED challenge, signs a permit2/EIP-712 authorization with a testnet wallet, and retries with PAYMENT-SIGNATURE. Put the testnet wallet key in a shell env var or the project .env — keep .env out of git.
How do I make Codex CLI pay an x402 endpoint? To make Codex CLI pay an x402 endpoint on the Radius testnet, drop the generated x402-pay SKILL.md into its skills directory (.codex/skills/x402-pay/SKILL.md). Point it at a grug402 scenario URL; it reads the 402 PAYMENT-REQUIRED challenge, signs a permit2/EIP-712 authorization with a testnet wallet, and retries with PAYMENT-SIGNATURE. Store the key in a shell env var; Codex reads it at runtime — never commit it.
How do I make Hermes pay an x402 endpoint? To make Hermes pay an x402 endpoint on the Radius testnet, drop the generated x402-pay SKILL.md into its skills directory (~/.hermes/skills/x402-pay/SKILL.md). Point it at a grug402 scenario URL; it reads the 402 PAYMENT-REQUIRED challenge, signs a permit2/EIP-712 authorization with a testnet wallet, and retries with PAYMENT-SIGNATURE. Use the Hermes env/secret store. Tirith blocks `curl | sh`, so install from the signed script rather than a piped installer.
How do I make IronClaw pay an x402 endpoint? To make IronClaw pay an x402 endpoint on the Radius testnet, delegate an ACP job that runs the x402-pay skill (WASM tool + .ironclaw/skills/x402-pay/SKILL.md). Point it at a grug402 scenario URL; it reads the 402 PAYMENT-REQUIRED challenge, signs a permit2/EIP-712 authorization with a testnet wallet, and retries with PAYMENT-SIGNATURE. The key lives in IronClaw's encrypted vault and is injected at the host boundary — the model never sees it.
How do I make OpenClaw pay an x402 endpoint? To make OpenClaw pay an x402 endpoint on the Radius testnet, drop the generated x402-pay SKILL.md into its skills directory (.claw/skills/x402-pay/SKILL.md). Point it at a grug402 scenario URL; it reads the 402 PAYMENT-REQUIRED challenge, signs a permit2/EIP-712 authorization with a testnet wallet, and retries with PAYMENT-SIGNATURE. Keep the key in the claw secret store / vault, not a plaintext env var.
How do I make Goose pay an x402 endpoint? To make Goose pay an x402 endpoint on the Radius testnet, add grug402 as an MCP server (~/.config/goose/recipes/x402-pay.yaml). Point it at a grug402 scenario URL; it reads the 402 PAYMENT-REQUIRED challenge, signs a permit2/EIP-712 authorization with a testnet wallet, and retries with PAYMENT-SIGNATURE. Store the key in the Goose keychain / configured secret and reference it from the recipe.
How do I make Pi pay an x402 endpoint? To make Pi pay an x402 endpoint on the Radius testnet, drop the generated x402-pay SKILL.md into its skills directory (~/.pi/skills/x402-pay/SKILL.md). Point it at a grug402 scenario URL; it reads the 402 PAYMENT-REQUIRED challenge, signs a permit2/EIP-712 authorization with a testnet wallet, and retries with PAYMENT-SIGNATURE. Use an env var or Pi's secret store; never inline the key.
How do I make OpenCode pay an x402 endpoint? To make OpenCode pay an x402 endpoint on the Radius testnet, drop the generated x402-pay SKILL.md into its skills directory (.opencode/skills/x402-pay/SKILL.md). Point it at a grug402 scenario URL; it reads the 402 PAYMENT-REQUIRED challenge, signs a permit2/EIP-712 authorization with a testnet wallet, and retries with PAYMENT-SIGNATURE. Store the key in a shell env var or a .env kept out of git.
How do I make Generic (MCP + SKILL.md) pay an x402 endpoint? To make Generic (MCP + SKILL.md) pay an x402 endpoint on the Radius testnet, drop the generated x402-pay SKILL.md into its skills directory (<your-agent>/skills/x402-pay/SKILL.md). Point it at a grug402 scenario URL; it reads the 402 PAYMENT-REQUIRED challenge, signs a permit2/EIP-712 authorization with a testnet wallet, and retries with PAYMENT-SIGNATURE. Provide the testnet wallet key via an environment variable or your agent's secret store — never inline it in the SKILL.md and never commit it.