# Block402

> Blockchain intelligence for AI agents.

Query blockchain data through a read-only, pay-per-request API with x402.

## Interfaces

- [API guide](https://api.block402.xyz/docs/api.md): methods, payment policy, recovery, and MCP.
- [OpenAPI](https://api.block402.xyz/openapi.json): available operations, exact prices, schemas, and examples.
- [MCP metadata](https://api.block402.xyz/mcp/server.json): Streamable HTTP adapter; clients need x402 payment support.
- [Agent setup](https://block402.xyz/agents/): installable CLI, budgeted local MCP bridge and downloadable agent skill.
- [Runnable demos](https://block402.xyz/agents/demos.html): Ethereum balance, transaction receipt and read-only simulation.

## Current Availability

Currently advertised chains: Bitcoin. OpenAPI and MCP list the available operations.
Payments: USDC on Base mainnet (eip155:8453).
The payment network is independent of the blockchain being queried.

Discovery does not authorize spending. Preserve private recovery keys and never sign a discovery-only challenge.