Tollbooth Examples — AI Agent Token Swaps with x402 Micropayments

Working, copy-paste examples for letting an autonomous AI agent swap tokens and screen tokens for honeypots/rug pulls using Tollbooth and the x402 payment protocol. No API keys, no accounts, no custody: the agent pays ~half a cent in USDC per call and signs its own transactions.

Supported chains: Solana, Base, Ethereum, Arbitrum, Polygon, Optimism, BSC, Avalanche (Jupiter aggregation on Solana, 0x on EVM chains).

How it works

1. GET /v1/tokens/:chain/:symbol — resolve a ticker like PEPE to contract addresses, ranked by DEX liquidity (free)
2. GET /v1/quote — fee-inclusive swap quote (free)
3. GET /v1/check/:chain/:token — honeypot / rug-pull safety check (x402, $0.01)
4. POST /v1/swap/build — unsigned, ready-to-sign swap transaction (x402, ~$0.005)
5. Your agent signs and submits with its own wallet. Tollbooth never touches keys or funds.

Tolls are payable in USDC on Base (gasless via EIP-3009) or Solana mainnet (gas sponsored by the facilitator — the payer wallet needs zero SOL). The @x402/fetch client handles the whole 402 payment loop automatically.

Run the examples

npm install --legacy-peer-deps

# free endpoints, no wallet needed
npx tsx examples/01-resolve-and-quote.ts

# paid endpoints: fund a wallet with a little USDC on Base first
PAYER_KEY=0x... npx tsx examples/02-safety-check.ts
PAYER_KEY=0x... TAKER=<your wallet> npx tsx examples/03-build-swap.ts

# pay tolls from a Solana wallet instead (USDC on Solana mainnet, no SOL needed)
SOLANA_PAYER_KEYPAIR=/path/to/keypair.json npx tsx examples/04-solana-payer.ts

Use from MCP (Claude, Cursor, any MCP client)

Tollbooth also ships an MCP server exposing resolve_token, get_quote, check_token, build_swap and get_receipt as tools. Example config in mcp.json.

Docs

• Agent usage guide: https://api.tollboothswap.xyz/skill.md
• Full tutorial: https://api.tollboothswap.xyz/guides/agent-swaps.md
• Service manifest: https://api.tollboothswap.xyz/.well-known/x402-service
• x402 Bazaar (service discovery for agents): https://docs.cdp.coinbase.com/x402/bazaar

Keywords

AI agent token swap, x402 payment protocol example, autonomous agent DeFi, Solana swap API for agents, honeypot checker API, rug pull detection API, non-custodial swap transaction builder, USDC micropayments, HTTP 402, machine-to-machine payments, Jupiter aggregator API, 0x swap API, MCP DeFi tools.

License

MIT