# Penniless Data Utilities

Nine deterministic data and lookup tools for AI agents, paid per call in USDC.
REST advertises both native MPP and [x402](https://x402.org); MCP uses x402 v2. No accounts, no API keys, no rate-limit
tiers. Every tool is pure computation or a keyless public lookup — none of them
call another AI model, so results are reproducible.

- Live endpoint (MCP): https://penniless-json-repair.sjaman.workers.dev/mcp
- Live endpoint (REST): https://penniless-json-repair.sjaman.workers.dev
- Discovery: `/health`, `/openapi.json`, `/llms.txt`, `/.well-known/x402`

## Pricing

`$0.001` USDC per call. REST advertises native MPP plus x402 v2 (`eip155:8453`, scheme `exact`); MCP uses x402 v2.

Base x402 settlements are verified by the free-tier [PayAI](https://facilitator.payai.network) facilitator. Native MPP is negotiated by `mppx`. Recipient (`payTo`): `0x3D98800c64C345950E1eAaa076D88C12d1BF5F37`.

## Connect over MCP

Any MCP client that speaks streamable HTTP can connect directly:

```json
{
  "mcpServers": {
    "penniless-data-utilities": {
      "type": "http",
      "url": "https://penniless-json-repair.sjaman.workers.dev/mcp"
    }
  }
}
```

The transport is stateless — no session id is issued or required, and every
request is independent. `initialize` and `tools/list` are free. An unpaid
`tools/call` returns an x402 payment-required payload in `result.content[0].text`
(and `result.structuredContent`); attach the signed payment as
`params._meta["x402/payment"]` and repeat the call.

If you use an x402-aware MCP client, `@x402/mcp` handles that exchange for you.

## Tools

| MCP name           | REST path               | Arguments                          | Returns |
| ------------------ | ----------------------- | ---------------------------------- | ------- |
| `repair_json`      | `POST /repair/json`     | `{input}`                          | repaired JSON + which fixes applied |
| `yaml_to_json`     | `POST /yaml/tojson`     | `{input}`                          | parsed value + warnings |
| `cron_next_run`    | `POST /cron/nextrun`    | `{expr, after?}`                   | next UTC fire time |
| `text_diff`        | `POST /diff`            | `{old, new, context?}`             | unified diff + counts |
| `text_extract`     | `POST /text/extract`    | `{input, numbers?, codeBlocks?}`   | text, title, headings, links, URLs, emails |
| `domain_whois`     | `POST /domain/whois`    | `{domain}`                         | registrar, statuses, expiry, nameservers, DNSSEC |
| `dns_lookup`       | `POST /dns/lookup`      | `{domain, type?}`                  | DoH answers for A/AAAA/CNAME/MX/TXT/NS/SOA/PTR/SRV/CAA |
| `github_repo_stats`| `POST /github/repo-stats`| `{repo}`                          | stars, forks, open issues, language, license |
| `email_validate`   | `POST /email/validate`  | `{email}`                          | syntax + live MX deliverability |

`POST /diagnose` is free: it classifies what is wrong with a malformed JSON
payload without returning the repaired output, so a caller can check whether
paying is worthwhile before paying.

### Example (REST + x402 client)

Any x402 v2 client works. With the reference TypeScript client and a viem account:

```js
import { x402Client } from "@x402/core/client";
import { registerExactEvmScheme } from "@x402/evm/exact/client";
import { wrapFetchWithPayment } from "@x402/fetch";
import { privateKeyToAccount } from "viem/accounts";

const client = new x402Client();
registerExactEvmScheme(client, { signer: privateKeyToAccount(key), networks: ["eip155:8453"] });
const pay = wrapFetchWithPayment(fetch, client);

const res = await pay("https://penniless-json-repair.sjaman.workers.dev/repair/json", {
  method: "POST",
  headers: { "content-type": "application/json" },
  body: JSON.stringify({ input: "{foo: 'bar',}" }),
});
// -> { ok: true, repaired: { foo: "bar" }, applied: ["unquoted-keys","single-quotes","trailing-commas"] }
```

`wrapFetchWithPayment` handles the 402 round-trip: it receives the requirement,
signs the USDC authorization, retries, and only returns a `200` once the
facilitator has settled.

## Development

```bash
npm install
npm test        # 133 tests, runs fully offline (facilitator + upstream are injected)
npx wrangler dev
npx wrangler deploy
```

Environment (set in `wrangler.toml`): `X402_NETWORK`, `X402_FACILITATOR`,
`X402_PRICE`, `X402_PAY_TO`. Production also has an encrypted Cloudflare secret
`MPP_SECRET_KEY` used only to authenticate MPP challenges. Wallet private keys are
never deployed to the Worker.

## Maintainer

GitHub: [@danielarif26](https://github.com/danielarif26)