Verified x402 Catalog

io.github.withgrokbotv0.4.0Updated Oct 3, 2026

Which x402 pay-per-call endpoint delivered for a task at a price? Facts from our own paid calls.

VerifiedStreamable HTTPWeb executableFinance Web Search & Scraping Data & Analytics

Overview

AI-generated overview

Lets an assistant query a static catalog of x402 pay-per-call services, with results from the publisher's own paid test calls.

What it does: Exposes three tools over a remote Streamable HTTP endpoint: search_catalog and get_service read the published catalog of x402 pay-per-call services, and lookup returns services matching a task and maximum price, sorted by known-answer pass rate over the publisher's paid calls, then by price. Each result carries Base settlement receipts and check outcomes. The same tools are also available as a small local stdio server.
When to use it: Useful when an agent needs to pick a pay-per-call x402 endpoint for a task such as web search and wants price and reliability facts before paying. It is a lookup and comparison aid, not a payment or execution service.
Requirements: Remote endpoint over Streamable HTTP; no key or account. The lookup tool shares the client name vc-mcp, which gets five free lookups per client per UTC day; beyond that the endpoint returns HTTP 402 and does not pay. A local stdio variant exists and needs Python.

Before you install

Paid lookups cost $0.02 USDC on Base per call after the free tier, settled through a public facilitator; the MCP lookup tool itself does not pay and only reports the 402. The catalog is the publisher's own paid-call evidence, not independent verification, and results can be contested only via a GitHub issue.

Installation

In SourceWeft

Open Verified x402 Catalog in the dashboard and add it to a workspace.
Enable the server for the chats that should use its tools.

Web executable via Streamable HTTP. Remote servers run from the web runtime once configured in a workspace.

Other MCP clients

Add this to your client's mcpServers config.

{
  "mcpServers": {
    "verified-catalog": {
      "type": "http",
      "url": "https://verified-catalog-lookup.withgrokbot.workers.dev/mcp"
    }
  }
}

README

Verified Pay-Per-Call Catalog

A static, machine-readable catalog of pay-per-call (x402) services for AI agents, with factual results of our own automated checks. Published by @WithGrokBot.

Try it in one line

Which x402 web-search endpoint delivered on our last paid calls, at $0.01 or less? No key; 5 free lookups per client per UTC day:

curl -s "https://verified-catalog-lookup.withgrokbot.workers.dev/v1/lookup?task=web-search&max_price=0.01&ref=via-readme"

curl -s "https://verified-catalog-lookup.withgrokbot.workers.dev/v1/lookup?task=web-search&max_price=0.01&ref=via-readme"

const r = await (await fetch("https://verified-catalog-lookup.withgrokbot.workers.dev/v1/lookup?task=web-search&max_price=0.01&ref=via-readme")).json();

const r = await (await fetch("https://verified-catalog-lookup.withgrokbot.workers.dev/v1/lookup?task=web-search&max_price=0.01&ref=via-readme")).json();

Results are sorted by known-answer pass rate over our last paid calls, then price, each with its Base settlement receipts. Other tasks: /v1/tasks. Optional client=<your agent name>; ref only says where you found the link.

Pricing

5 free lookups per client per UTC day. The client is your client value when you send one, otherwise a salted hash of your IP (raw IPs are never stored). The counter resets at 00:00 UTC. Only /v1/lookup is metered; /v1/tasks, /openapi.json and the static catalog files stay free.
After that, $0.02 USDC on Base per lookup via x402. The lookup answers HTTP 402 with a v2 PAYMENT-REQUIRED header (exact scheme, eip155:8453, USDC, payTo 0x37cfCC8a29e9ff9458902B29E31E42dc7B718674). Retry with a PAYMENT-SIGNATURE (or X-PAYMENT) header; the payment is verified and settled through the public PayAI x402 facilitator, and the settlement tx comes back in the PAYMENT-RESPONSE header and the response's access block.
Payment never changes results, sort order or listings. It buys query access only. Free, paid and exempt lookups run the same code on the same data and get identical results; no seller can pay for placement, and no check result or known-answer outcome depends on who paid. Every lookup response repeats this in payment_policy.

Remote MCP server (free)

https://verified-catalog-lookup.withgrokbot.workers.dev/mcp (Streamable HTTP, stateless JSON-RPC, no key). Same 3 tools and results as mcp/server.py: search_catalog, get_service and lookup. lookup uses the client name vc-mcp, so it shares that client's 5 free lookups per UTC day; after that it reports the 402 and does not pay. Registry name: io.github.withgrokbot/verified-catalog (server.json).

Always-paid endpoint (x402)

GET https://verified-catalog-lookup.withgrokbot.workers.dev/v1/lookup/paid?task=web-search&max_price=0.01 takes the same parameters and returns the same result as /v1/lookup, for $0.02 USDC on Base per call with no free quota. Its 402 carries x402 Bazaar discovery metadata (extensions.bazaar); it is also listed in /openapi.json (x-payment-info) and /.well-known/x402. Bad parameters get a 400 before anything is settled.

Files

index.html, services/<id>.html, methodology.html: the site (no JavaScript, no requests to other hosts)
catalog.json, services/<id>.json, llms.txt, .well-known/agent-card.json: machine-readable
data/services.json: the seed listings (source and retrieval date on each), data/site.json: brand/repo settings
results/latest.json, results/history.jsonl, results/raw/<run>/<id>.json, results/spend_ledger.json: check results and evidence
scripts/run_checks.py: run checks (free/dry-run by default) and rebuild; scripts/build_site.py: rebuild only
data/quality_tests.json, scripts/quality.py: known-answer tests run on every paid call (pass/fail; broken services are "facts only")
receipts.json: every paid call (time, charged, settlement tx with Basescan link, delivered, known-answer result)
worker/: reliability lookup, a Cloudflare Worker (GET /v1/lookup?task=web-search&max_price=0.01&n=5) that reads catalog.json and receipts.json from this site and counts distinct clients (see worker/README.md)
mcp/server.py: small stdio MCP server with search_catalog, get_service (read catalog.json) and lookup (calls the Worker); the Worker serves the same tools remotely at /mcp
server.json: official MCP Registry entry (remote server)
scripts/demand_weekly.py: weekly count of distinct lookup clients -> results/demand_weekly.json
.github/workflows/daily.yml: daily free checks and commit

Run

python3 scripts/run_checks.py            # free checks, no payment (default)python3 scripts/build_site.py            # rebuild pages from data/ and results/python3 tests/run_tests.py               # acceptance tests (Node 18+ for the Worker tests)

python3 scripts/run_checks.py            # free checks, no payment (default)python3 scripts/build_site.py            # rebuild pages from data/ and results/python3 tests/run_tests.py               # acceptance tests (Node 18+ for the Worker tests)

Paid checks exist but are off by default. They need --pay, a wallet file outside this folder (--wallet), and pip install -r scripts/requirements-pay.txt. Hard caps: $0.10 per call, $1.00 per UTC day, $20.00 lifetime; only USDC "exact" on Base is ever signed.

We publish facts only, no grades. We hold no customer funds and are not a party to any seller transaction; lookup fees after the free tier go to our own wallet. To contest a result, open a GitHub issue (see methodology.html#contest).

License

MIT, see LICENSE.

Source: README.md at commit 5c2a89c

Tools

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Version history

v0.4.0LatestOct 3, 2026