sigtap-agent-tools — AI agent tools over x402 micropayments

Free preview of every tool, no wallet needed. A Python client + hosted API where each call costs $0.0005–$0.01, settled in USDC on Base mainnet via the x402 protocol (HTTP 402 + PAYMENT-REQUIRED → sign → PAYMENT-SIGNATURE retry → settled on-chain). No signup, no API keys — the signed payment IS the credential.

60-second quickstart (Python)

pip install sigtap-agent-tools

from sigtap_agent_tools import client

# 1. Free preview of ANY paid tool — a 200 demo sample, no wallet:
print(client.preview("tools/hash", text="hello"))
# {'preview': True, 'route': '/tools/hash', 'sha256': '2cf…', 'hex': '686…',
#  'crc32': '361…', 'truncated': True, 'paid_unlocks': 'unlimited text length, ...}

# 2. See the exact payment terms a paid call would accept:
status, reqs = client.challenge("tools/uuid", version="ulid", count=1)
print(status)  # 402 — decodes the base64 PAYMENT-REQUIRED header for you
# {'x402Version': 2, 'resource': 'https://...', 'accepts': [{'network': 'eip155:8453', ...}]}

# 3. Paid call: sign the challenge with any x402 client, then retry with the signature:
#    result = client.paid_call("tools/uuid", {"PAYMENT-SIGNATURE": "<signed v2 payload>"},
#                              version="ulid", count=1)

Call it from an agent (copy-paste, verified end-to-end with funded calls)

Official x402 SDK — Node.js with @x402/fetch (settled on-chain 2026-09-06):

import { wrapFetchWithPaymentFromConfig } from "@x402/fetch";
import { ExactEvmScheme } from "@x402/evm";
import { privateKeyToAccount } from "viem/accounts";

const account = privateKeyToAccount(process.env.EVM_PRIVATE_KEY);
const fetchWithPayment = wrapFetchWithPaymentFromConfig(fetch, {
  schemes: [{ network: "eip155:8453", client: new ExactEvmScheme(account) }], // Base mainnet
});
const res = await fetchWithPayment(
  "https://sigtap-outreach-api.sigtap.workers.dev/tools/uuid?count=1&version=ulid");
console.log(res.status, await res.text());
// 200 {"version":"ulid","count":1,"ids":["0PD1VZG5KCE10V6W4YW2PSWP2T"]}

More working snippets (including a zero-dependency Python wire-format client, settled 2026-09-07, tx 0xfc1b31c6…06f0): gist: working x402 snippets against sigtap

MCP server (13 tools, one-line config)

{ "mcpServers": { "sigtap-agent-tools": { "type": "http", "url": "https://sigtap-mcp.sigtap.workers.dev/mcp" } } }

Free touch (no wallet needed)

Paid endpoints (prices live-verified from /openapi.json)

Outreach intelligence (the money tools):

Micro-tools ($0.0005–$0.003):

x402 payment flow (one round-trip)

1. GET /tools/hash?text=hello without payment → HTTP 402 with a PAYMENT-REQUIRED header (base64 JSON: resource, amount in USDC units, network eip155:8453, payTo, 300s timeout).
2. Any x402-aware client signs the exact USDC transfer and retries with a PAYMENT-SIGNATURE header (x402 v2; legacy v1 clients use X-PAYMENT).
3. 200 + result. Settlement is visible on BaseScan.

Heads-up: the API is behind Cloudflare. Python's default Python-urllib User-Agent is blocked (403 error 1010). Any real UA works — requests, httpx and this package's client all send one.

Links

• HTTP API: https://sigtap-outreach-api.sigtap.workers.dev
• MCP server: https://sigtap-mcp.sigtap.workers.dev/mcp (health: /health)
• Agent-readable digest: https://sigtap-outreach-api.sigtap.workers.dev/llms.txt
• Catalog repo: https://github.com/unnamedaiagent/sigtap-agent-tools
• For humans: AI Outreach Kit, $19 — crypto checkout, free sampler PDF