Spec Driven Development
MCP Server that facilitates spec-driven development workflows, not just Vibe Coding.
Description from the maker (original English)
Check an x402 endpoint before your agent pays: pay, skip or recheck, with Ed25519-signed receipts.
These three are never merged into one score: opinions, measurements and popularity are different things.
We have not written a plain-language summary for this one yet. Below are the facts we read from the registry.
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Works in Claude on the web, desktop and mobile:
https://api.402xagent.com/mcpRun this in your terminal
claude mcp add --transport http verified-catalog https://api.402xagent.com/mcpPaste into .cursor/mcp.json in your project, or ~/.cursor/mcp.json
{
"mcpServers": {
"verified-catalog": {
"url": "https://api.402xagent.com/mcp"
}
}
}Your browser asks to open the app, then the app shows the settings and asks you to confirm. Key values are left empty for you to fill in.
Paste into .vscode/mcp.json in your project
{
"servers": {
"verified-catalog": {
"type": "http",
"url": "https://api.402xagent.com/mcp"
}
}
}Your browser asks to open the app, then the app shows the settings and asks you to confirm. Key values are left empty for you to fill in.
ChatGPT connects only to servers on the internet:
https://api.402xagent.com/mcpMenu names can differ slightly by plan and over time.
Your choice stays on this device in a cookie; no account needed.
These settings are generated from the maker’s registry entry. If the README says otherwise, follow the README.
Tool names and descriptions exactly as the server reported them on Nov 6, 2026. The maker wrote them, not us; we show them as plain text.
search_catalogBrowse or keyword-search the verified catalog of pay-per-call (x402) agent services. Use it when you don't know the task name or want to see what exists; use lookup to rank endpoints for a known task at a max price, and get_service for one id's full record. Read-only. No auth or
get_serviceFetch the complete catalog record for one known service id (e.g. from search_catalog or lookup results). Use search_catalog to find ids and lookup to rank services for a task; get_service has no per-call receipts, so for receipts with tx and Basescan links call lookup with endpoi
lookupRank x402 endpoints for a known task at or under a price: "which endpoint should I pay for task X at <= $Y?". Prefer it over search_catalog (keyword browsing, unranked) and get_service (one id's raw record). No auth or API key. Calls the hosted lookup service as client=vc-mcp; al
get_overnight_cos_packBuy and download the Overnight Chief of Staff Setup Pack ($9 USDC on Base via x402): 5 ready-to-paste bot prompts, an HTML morning-briefing template, and a PDF setup guide. Always paid — no free quota. Call without PAYMENT-SIGNATURE to receive payment requirements and the HTTP en
get_receiptFree: read a public 402xAgent receipt. Give id (sc-... from endpoint_spot_check's receipt_id, or a 10-hex crawl id) or url (latest live + crawl receipt for that URL). Receipts hold the listing URL, the live 402 terms, verdict, reason, reason_code, confidence, history summary, tim
endpoint_spot_checkDecision-shaped 402xAgent check of a public URL (private, loopback and link-local addresses blocked on every redirect hop) for an x402 PAYMENT-REQUIRED / 402 challenge. Every answer has reason_code (stable code) and confidence (high|medium|low); rules: https://402xagent.com/rules
payment_statusAfter you pay an x402 endpoint (Base USDC, EIP-3009 exact): did the payment land, and is it safe to sign a new one? Give payment_payload (the base64 PAYMENT-SIGNATURE you sent), or tx_hash, or from + nonce (+ valid_before). Returns status landed|not_landed|pending|canceled|unknow
x402_hygieneFree x402 hygiene score for an endpoint you run: {score, grade, deductions[{code, points, fix}]} from normal unpaid requests (never pays, never sends bad params). 20 per day per network, cached 24 h. Grades are returned only to you.
discoverFree discovery of x402 pay-per-call endpoints from 402xAgent's weekly crawl. Returns up to 20 endpoints matching the words in q (URL or source list), each with the verified (quoted) price, network, last_checked, stale flag, verdict pay|skip|recheck with its reason, and a receipt.
endpoint_reportPaid ($0.05 USDC on Base via x402, no free tier): the exact committed snapshots behind endpoint_spot_check's locked teasers: which payment terms changed in the last 30 days, when, from what to what, and the full hygiene checks. Pass the url and the commitment_ref from the free an
page_to_markdownFetch one public web page and return clean, LLM-ready Markdown of its main content (no nav, footers, ads or cookie banners; absolute links; tables kept) plus title, description, links, word_count and token_estimate. Respects robots.txt; skips login walls, paywalls and 401/403 pag
pdf_tablesExtract the tables (CSV, JSON, Markdown) and per-page text from one PDF at a public URL. Digital PDFs ~97% cell accuracy; scanned pages (OCR) ~80%. Priced per page via x402 USDC on Base: $0.005/page with ocr=never, $0.015/page with ocr=auto. Charged only if every page succeeds. M
We check information anyone can see; we have not read the code. Checks that do not apply are left out of the count. · Checked Nov 7, 2026
The registry name was verified with the GitHub account withgrokbot, which owns the repo
We have not read this repo from GitHub yet
We have not read this repo from GitHub yet
Responded in 90 ms (HTTP 200)
No sign-in needed
Read 12 tool descriptions and found no hidden instructions to the AI
Compared with every active server in this category in the registry. Stars count only when the publisher owns the repo.
It passed 3 of 3 applicable basic checks. We have not read the code. Before adding a key or token, see what access the server asks for and use a key with only the permissions you need.
The registry does not list a required key, though some servers ask you to sign in on first use.
It runs in the maker’s cloud. Connect over the internet with nothing to install, but what you send passes through the maker’s servers.
The GitHub repo last changed –, and the latest version (0.59.10) reached the registry 3 days ago.
Apps that support MCP, such as Claude Desktop, Claude Code, Cursor and VS Code. It connects by URL, so apps that accept remote MCP servers work too, such as ChatGPT in developer mode.
In the same category: Spec Driven Development, Remote Desktop Commander, Microsoft Exchange Online MCP
Servers in the same category from other makers, sorted by stars.
Reading a card:★ GitHub starsiThree pillars: reviews · checks · usageiUpdated = latest version published to the registryi
MCP Server that facilitates spec-driven development workflows, not just Vibe Coding.
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Copied from the maker’s repo as written. PopNx MCP has not reviewed or endorsed it. HTML, images and scripts are removed. Links lead off this site.
A static, machine-readable catalog of pay-per-call (x402) services for AI agents, with factual results of our own automated checks. Published by @402xAgent.
Discover (verdict-filtered index). GET https://api.402xagent.com/v1/discover?q= &verdict=pay|skip|recheck&limit= 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
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://api.402xagent.com/v1/lookup?task=web-search&max_price=0.01&ref=via-readme"
const r = await (await fetch("https://api.402xagent.com/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= ; ref only says where you found the link.
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.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_policy.https://api.402xagent.com/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).
GET https://api.402xagent.com/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.
Paid digital downloads sold via the same Worker over x402 (always paid; free lookup quota and SELF_CLIENTS do not apply):
$9 USDC on Base. GET https://api.402xagent.com/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.index.html, services/ .html, methodology.html: the site (no JavaScript, no requests to other hosts)catalog.json, services/ .json, llms.txt, .well-known/agent-card.json: machine-readabledata/services.json: the seed listings (source and retrieval date on each), data/site.json: brand/repo settingsresults/latest.json, results/history.jsonl, results/raw/ / .json, results/spend_ledger.json: check results and evidencescripts/run_checks.py: run checks (free/dry-run by default) and rebuild; scripts/build_site.py: rebuild onlydata/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 /mcpserver.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 commitpython3 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).
MIT, see LICENSE.