Spec Driven Development
by formulahendry
MCP Server that facilitates spec-driven development workflows, not just Vibe Coding.
Runs on your computer★ 440MITUpdated 14 months ago
Install
Assay
Overview
Description from the maker (original English)
x402 service-quality oracle: check a service's paid-probe quality tier and score before paying it.
PopNx MCP’s three pillars
These three are never merged into one score: opinions, measurements and popularity are different things.
- User voiceiNo reviews yetReviews open together with accounts in a later step
- Our basic checksi1 of 1 passedChecked from public information; code not scanned yet
- UsageiNot measured yet★ –
What you can do with it
We have not written a plain-language summary for this one yet. Below are the facts we read from the registry.
- Connection: Runs on your computer
- Transport: stdio
- Category: Other
- You need to fill in: ASSAY_WALLET_KEY
Install
Pick the AI app you use, then copy the settings.
Before you install
- Basic checks: 1 of 1 passed
- Runs on your computer with your user’s permissions (files, network, apps).
- You fill in yourself:
ASSAY_URL,ASSAY_WALLET_KEY
Values marked secret are keys to your account. Never share them or paste them into a chat.
You need
- npmNode.js installed (for the npx command)
Which app do you use?
Pick your app above. We remember it, so next time the button says “Install in …”.
Open Claude Desktop → Settings → Developer → Edit Config, and paste this into claude_desktop_config.json
{
"mcpServers": {
"assay": {
"command": "npx",
"args": [
"-y",
"assay-oracle-mcp"
],
"env": {
"ASSAY_URL": "your-value",
"ASSAY_WALLET_KEY": "your-value"
}
}
}
}Run this in your terminal
claude mcp add assay --env ASSAY_URL=your-value --env ASSAY_WALLET_KEY=your-value -- npx -y assay-oracle-mcpFill in the empty values before running it.
Or copy the settings yourself
Paste into .cursor/mcp.json in your project, or ~/.cursor/mcp.json
{
"mcpServers": {
"assay": {
"command": "npx",
"args": [
"-y",
"assay-oracle-mcp"
],
"env": {
"ASSAY_URL": "your-value",
"ASSAY_WALLET_KEY": "your-value"
}
}
}
}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.
Or copy the settings yourself
Paste into .vscode/mcp.json in your project
{
"servers": {
"assay": {
"type": "stdio",
"command": "npx",
"args": [
"-y",
"assay-oracle-mcp"
],
"env": {
"ASSAY_URL": "your-value",
"ASSAY_WALLET_KEY": "your-value"
}
}
}
}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.
This one runs on your computer, and ChatGPT can only connect to servers on the internet. Pick another app.
Your choice stays on this device in a cookie; no account needed.
Values you fill in
ASSAY_URLenvAssay instance to query (default: https://assay.nominal-labs.com)- Optional Base wallet private key; when set, get_score auto-purchases full reports ($0.005, hard-capped 0.01 USDC/call)
These settings are generated from the maker’s registry entry. If the README says otherwise, follow the README.
What it can do
Runs on your computer; the tool list appears in your AI app after you install it.
Basic checksi
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 8, 2026
- ✓ Pass
Maker matches the repo
The registry name was verified with the GitHub account JasonCZMeng, which owns the repo
- … Not checked yet
Still maintained
We have not read this repo from GitHub yet
- … Not checked yet
Has a licence
We have not read this repo from GitHub yet
- – Not applicable
Endpoint responds
This one runs on your computer; there is no internet endpoint
- – Not applicable
Sign-in with OAuth
Runs on your computer and uses local settings instead
- … Not checked yet
No hidden instructions in tool descriptions
Runs on your computer; we can only read tool lists from internet endpoints
Compared with others in Otheri
- More stars than 0% of the other 18428 servers in this category
- Published to the registry more recently than 19% of the other 18428 servers in this category
- Basic checks equal to or better than 100% of the other 18428 servers in this category
Compared with every active server in this category in the registry. Stars count only when the publisher owns the repo.
Common questions
Is Assay safe?
It passed 1 of 1 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.
What keys or codes does it need?
You need to fill in: ASSAY_WALLET_KEY
Does it run on my computer or in the cloud?
It runs on your computer. Your AI app starts it when needed, and data does not pass through the maker’s servers (unless it calls an online service itself).
Is it still maintained?
The GitHub repo last changed –, and the latest version (0.2.0) reached the registry 3 months ago.
Which apps can use it?
Apps that support MCP, such as Claude Desktop, Claude Code, Cursor and VS Code. You also need Node.js on your computer.
What can I use instead?
In the same category: Spec Driven Development, Remote Desktop Commander, Winecellarbuilders
Alternatives
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
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by desktop-commander
Remote Desktop Commander: use files, terminal and processes on your own computers from any AI app.
Runs in the cloud★ 211Updated 3 days ago
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Winecellarbuilders
by itsryanarmani
Find the team for your wine room.
Runs in the cloudUpdated today
Install
README from the maker
Open the README
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.
Assay
The quality oracle for the x402 agent economy — x402 being the open protocol that lets machines pay for HTTP APIs with stablecoin micropayments. Assay pays real USDC to probe machine-payable services, verifies what actually comes back, and sells the resulting quality scores — every rating backed by an on-chain payment receipt and a Bitcoin-anchored evidence trail.
Live: assay.nominal-labs.com · Leaderboard · Agent guide (SKILL.md)
The problem
Agents are starting to buy API responses from other machines over x402 — HTTP 402 payment challenges settled in USDC on Base (Coinbase's Ethereum L2), no accounts, no invoices. Tens of thousands of services already advertise themselves in discovery catalogs like the Coinbase x402 Bazaar. But an agent holding a wallet has no way to know which of them actually deliver: whether payment settles, whether the response matches the advertised schema, whether the data is even true. The trust signals that exist score *liveness* — uptime, latency, payment telemetry. Nobody pays these services and verifies what actually comes back. Paying to find out is the only real test — so that's what Assay does, on a schedule, with its own money, so your agent doesn't have to.
How scoring works
Assay probes a curated set of x402 services several times a day, at randomized times, with real paid requests. Each probe is scored on four independent checks:
| Component | Weight | Question it answers |
|---|---|---|
| Settlement | 40% | Did payment settle and a response come back? (tx hash recorded) |
| Schema | 30% | Does the response match the service's advertised output schema? |
| Ground truth | 20% | Does the data agree with an independent reference source? |
| LLM judge | 10% | Does the response deliver what the service claims to sell? |
Weights renormalize over the components a service has data for. A service's composite score (0–100) is computed over its trailing 30 days of probes and publishes only once it has 20+ probes spread across days — no scores from thin evidence. Tiers: gold ≥ 85, ok ≥ 60, otherwise avoid.
Why the history can't be quietly rewritten
Scores are only as trustworthy as the evidence behind them, so the probe corpus is append-only and publicly anchored:
- Every probe row (settlement result, response hash, paid amount, tx hash) becomes a leaf in a per-day Merkle tree; the root is anchored to Bitcoin via OpenTimestamps (OTS) after a safety lag.
- Daily Merkle roots and their OTS proofs are public at
/api/digests. - Anything that ever touches recorded history — migrations, re-anchoring — is logged in the open in docs/CORPUS-LOG.md.
The accumulating corpus is the point: anyone can copy the code, but nobody can backdate the evidence — the anchors prove when each day's records existed.
Using Assay
HTTP — the oracle itself is an x402 service at https://assay.nominal-labs.com. Paid endpoints answer with an HTTP 402 payment challenge that any x402 client settles automatically:
| Endpoint | Price | Returns |
|---|---|---|
GET /score/{url-encoded service URL} | $0.005 USDC (Base) | Composite, component breakdown, trend, probe count |
GET /tier/{url-encoded service URL} | free | gold / ok / avoid / unrated verdict |
GET /leaderboard | free | All scored services, ranked |
GET /api/digests | free | Daily Merkle roots + OTS proofs |
MCP server (Model Context Protocol — how AI assistants call external tools) — assay-oracle-mcp on npm and the official MCP registry. For Claude Code:
claude mcp add assay -- npx -y assay-oracle-mcpSpend guard — assay-x402-guard wraps your agent's paying fetch and throws *before* money moves to a service rated avoid:
import { wrapFetchWithAssay } from "assay-x402-guard";// payFetch = your x402-paying fetch (e.g. wrapFetchWithPayment from @x402/fetch) const safeFetch = wrapFetchWithAssay(payFetch);
More background: SUMMARY.md (what/why) and docs/specs/ (design).
Development (any OS)
cp .env.example .envand fill in (all vars documented in the example):
PROBE_WALLET_KEY: fresh dedicated wallet, ≤ $50 USDC on Base mainnet (no ETH needed — x402 "exact" settles via facilitator using EIP-3009 signatures)ANTHROPIC_API_KEY: the LLM judge
npm install && npm test(no network or wallet needed for the suite)npx tsx scripts/verify-env.mts— preflight; fails loudly on misconfigurationnpm run dev— server on :3402 (localhost-bound by default) plus crons: catalog ingest (6h), probe sweeps (every 4h at :15 + jitter), daily digest anchoring- Curate services to probe:
npm run curate -- list- write a template JSON (see docs/templates/), then
npm run curate -- add
- Ops dashboard: http://127.0.0.1:3402/dashboard (pause/resume, probe-now, retire/restore)
The money path is deliberately paranoid: a hard per-payment cap, a daily budget summed from actually-settled amounts, and fail-closed guards on unparsable payment requirements — all unit-tested with injected fakes.
Note that a fresh deployment starts with an empty corpus — the scores are only as good as the probe history behind them.
Production deploys
How the reference instance at assay.nominal-labs.com is operated (adapt for your own): commit to main, ship to the VPS as a git bundle, apply with git reset --hard + systemctl restart assay (provisioning and update runbook in deploy/README.md). The SQLite file at data/assay.db is the product — never recreate it; the VPS keeps daily on-box snapshots via /etc/cron.daily/assay-backup.
Payments: PAYMENTS_ENABLED=true + RECEIVE_WALLET_ADDRESS + a Coinbase Developer Platform (CDP) API key (CDP_API_KEY_ID/CDP_API_KEY_SECRET — the server auto-selects the CDP facilitator for Base mainnet when both are set).
Layout
src/— the whole system: server + APIs, prober, scoring, digests, ingest, pagesmcp/—assay-oracle-mcp: MCP server (check_service,get_score,top_services)middleware/—assay-x402-guard: wrapFetchWithAssay spend-guard for agentstests/— vitest; money-path logic unit-tested with injected fakesscripts/— preflight, wallet rotation, smoke tests;start-assay.*are legacy launchers from an earlier home-PC deployment, superseded by systemddeploy/— Caddyfile, systemd unit, provisioning runbookdocs/— CORPUS-LOG.md (public integrity log), specs, templates
License
MIT — the whole repo, including the npm packages (mcp/ and middleware/). The code is freely reusable; the evidence corpus and its Bitcoin-anchored history are what a fresh deployment can't copy.