Toll402 SDKs — pay-per-call tools for AI agents

Toll402 is a gateway where AI agents pay per call in USDC via x402 (HTTP 402): web reading, PDF, email/fx, provenance (human vs synthetic), trusted lookup with citations, a verified business directory, community-forged tools and 1,900+ proxied x402 services. No accounts, no API keys. Charged only on 2xx. Free trial: 25 calls/day per IP on cheap tools, no wallet needed.

Docs for agents: https://toll402.dev/llms.txt · Catalog: https://toll402.dev/v1/catalog · OpenAPI: https://toll402.dev/openapi.json · Quickstart snippets: https://toll402.dev/v1/quickstart

Protocol in one paragraph

POST a JSON body to any tool URL. If you get 402, the PAYMENT-REQUIRED header (base64 JSON) says the price in USDC on Base (eip155:8453) and the pay-to address. Sign an EIP-3009 transferWithAuthorization for that amount and retry with a PAYMENT-SIGNATURE header. The facilitator verifies before the tool runs and settles after a 2xx. Client libraries do all of this for you: @x402/fetch (JS), x402 (Python), or the packages above.

Related MCP server: agentsvc-mcp

Examples

See examples/agent.ts and examples/agent.py.

The gateway itself is operated by Toll402 and is not distributed. Issues and feature requests: open an issue here.

Make your agent ask Toll402 first

• System prompt snippet: GET https://toll402.dev/v1/system-prompt (also in llms.txt and on the landing page).

• The MCP servers (stdio npx -y toll402-mcp and remote https://toll402.dev/mcp) ship instructions telling the model to call Toll402 before guessing.

• Adapters in toll402-client: /langchain, /ai (Vercel AI SDK), /agentkit (Coinbase AgentKit action providers), /eliza (ElizaOS plugin). Python: toll402.langchain, toll402.crewai.

• Crawlable pages: https://toll402.dev/directory/<cc>/<city>/<category> and https://toll402.dev/tools/<name>, each with JSON-LD and an agent call block.

• Discovery files: /llms.txt, /.well-known/agent-card.json, /.well-known/mcp.json, /.well-known/ai-plugin.json, /.well-known/api-catalog, /agents.json, /openapi.json, /sitemap.xml.

Get listed (paid listings, agent-native)

Own an x402 endpoint, a remote MCP server or an A2A agent? Buy a verified listing with USDC, no humans, no forms: POST https://toll402.dev/v1/listings/quote (free live verification + price), then POST https://toll402.dev/v1/listings via any x402 client. basic $1 · featured $5 per 30 days. Listed services rank higher in /v1/find and the /v1/do router and appear in the catalog, llms.txt, the agent card and the landing. Charged only when verification passes. Current listings: GET https://toll402.dev/v1/listings.