mcpField
4
402xAgent

402xAgent

Remote
402xagent.comDeveloper Tools1Updated today

About 402xAgent

402xAgent catalogs x402 pay-per-call services with factual results from automated checks, helping AI agents decide whether to pay, skip, or recheck before a call. The catalog is available through an API, website, and MCP, with results including prices, networks, and signed receipts.

Key features

  1. 01Search and filter the x402 catalog
  2. 02Show pay, skip, or recheck verdicts
  3. 03Include quoted prices, networks, and skip reasons
  4. 04Attach Ed25519-signed receipts
  5. 05Look up verified results for paid calls
  6. 06Publish machine-readable catalog files

Use cases

  1. 01Filter services by task and price before payment
  2. 02Recheck endpoints when terms are stale
  3. 03Find verified service results for a task

MCP support

The remote MCP server provides `search_catalog`, `get_service`, and `lookup` tools. `lookup` uses a free quota and reports HTTP 402 when that quota is exhausted; it does not pay on the caller's behalf.

Configuration

Remote servers need no local install. Pick your client, then copy the config or install in one click.

Endpointhttps://api.402xagent.com/mcp
Copy install command
Claude CodeTerminal
Cursor.cursor/mcp.json
VS Code.vscode/mcp.json
Claude Desktopclaude_desktop_config.json
Windsurf~/.codeium/windsurf/mcp_config.json

Run commands in a terminal; paste JSON into the client’s MCP config and restart. Servers that need sign-in will prompt on first connect.

All endpoints
Streamable HTTPhttps://api.402xagent.com/mcp
Streamable HTTPhttps://verified-catalog-lookup.withgrokbot.workers.dev/mcp

Tools

7
ParameterTypeRequiredDescription
limitintegerNoOptional. Maximum number of results, 1-100 (default 20).
querystringNoOptional. Space-separated words; every word must appear (case-insensitive) in the service id, name, category, description or provider. Omit to list all. Examples: "search", "crypto news".
categorystringNoOptional. Case-insensitive substring of the service category, e.g. "web search", "news", "on-chain data", "weather", "public records", "utility".
max_price_usdnumberNoOptional. Keep services whose advertised price per call is at or below this many USD, e.g. 0.01.
reachable_onlybooleanNoOptional (default false). If true, keep only services that were reachable in the latest check.

Details

From the project 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.

Discover (verdict-filtered index). GET https://api.402xagent.com/v1/discover?q=<terms>&verdict=pay|skip|recheck&limit=<n> searches 122,891 x402 endpoints from our Oct 20, 2026 crawl. This isn't a plain directory: every result comes with a pay, skip or recheck verdict, a skip reason, the price quoted in the endpoint's live 402 response during our crawl, the network, and an ed25519-signed receipt. Results are facts from an unpaid crawl probe, not endorsements. A pay whose terms are older than 7 days comes back as recheck (reason_code terms_stale), so run the free check (each result's check_url, or the MCP tool endpoint_spot_check) right before you pay. Also available as the MCP tool discover at https://api.402xagent.com/mcp. — 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"
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.

Products

Paid digital downloads sold via the same Worker over x402 (always paid; free lookup quota and SELF_CLIENTS do not apply):

  • Overnight Chief of Staff Setup Pack — $9 USDC on Base. GET https://verified-catalog-lookup.withgrokbot.workers.dev/v1/products/overnight-cos-pack (or MCP tool get_overnight_cos_pack). Unpaid calls return HTTP 402 with Bazaar discovery metadata. After payment: prompts, HTML morning-briefing template, and PDF guide.

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)

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.

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