agent-payment-x402

# Agent Payment Execution (x402) Enable AI agents to make policy-gated payments with built-in spending controls. Uses the x402 HTTP payment protocol and MCP tools so agents can pay for external services, APIs, or other agents without custodial risk. ## When to Use Use when: your agent needs to pay for an API call, purchase a service, settle with another agent, enforce per-task spending limits, or manage a non-custodial wallet. Pairs naturally with cost-aware-llm-pipeline and security-review skills. ## Decision Tree Choose the integration path based on whether your agent is buying access to a paid API or charging others for one: | Need | Recommended path | |------|------------------| | Agent pays a 402-gated API on Base or another agentwallet-supported chain | Use `agentwallet-sdk` as an MCP payment server with strict spending policy | | Agent pays a 402-gated API on X Layer | Use OKX Agent Payments Protocol from `okx/onchainos-skills`; `okx-x402-payment` is a deprecated legacy alias | | TypeScript API charges agents | Use OKX Payments TypeScript seller SDK docs for Express, Hono, Fastify, or Next.js | | Go API charges agents | Use OKX Payments Go seller SDK docs for Gin, Echo, or `net/http` | | Rust API charges agents | Use OKX Payments Rust seller SDK docs for Axum | | Java API charges agents | Use OKX Payments Java seller SDK docs for Spring Boot 2/3, Java EE, or Jakarta | | Python API charges agents | Check the current OKX Payments repository before implementation; a Python seller guide may not be available | ## Supported Networks - `agentwallet-sdk`: use the package docs to confirm current network coverage before production. Base Sepolia is the safest development default; Base mainnet is the production path called out by the original skill. - OKX Payments / X Layer: current seller docs target X Layer (`eip155:196`) and USDT0 settlement. Fetch current SDK docs before generating production code because payment packages and facilitator behavior can change quickly. ## How It Works ### x402 Protocol x402 extends HTTP 402 (Payment Required) into a machine-negotiable flow. When a server returns `402`, the agent's payment tool negotiates price, checks budget, signs a transaction, and retries only inside the policy and confirmation boundary set by the orchestrator. ### Spending Controls Every payment tool call enforces a `SpendingPolicy`: - **Per-task budget** — max spend for a single agent action - **Per-session budget** — cumulative limit across an entire session - **Allowlisted recipients** — restrict which addresses/services the agent can pay - **Rate limits** — max transactions per minute/hour ### Non-Custodial Wallets Agents hold their own keys via ERC-4337 smart accounts. The orchestrator sets policy before delegation; the agent can only spend within bounds. No pooled funds, no custodial risk. ## MCP Integration The payment layer exposes standard MCP tools that slot into any Claude Code or agent harness setup. > **Security note**