X402 Oracle Server MCP Server

Hosannaith

A pay-per-call x402 reliability oracle — live on Algorand Mainnet.

🔗 Live app: hosannaith.com · API: api.hosannaith.com · Repo: github.com/cameron4316/x402-oracle-server

The problem

As x402 turns APIs into pay-per-request services, agents increasingly pay endpoints they didn't build — with no way to know if an endpoint is actually reliable before sending real USDC. Dead or misbehaving endpoints silently waste money and break automated flows.

What it does

Hosannaith is itself an x402 endpoint. It independently and continuously monitors other x402 endpoints and sells a verified reliability score on demand: uptime, correct 402 behaviour, and latency percentiles, backed by real accumulated history — with every response flagging its confidence ("history" for a stood-behind score, "one-shot" for a target queried for the first time). It's x402 monitoring x402.

GET https://api.hosannaith.com/reliability?target=<x402-endpoint-url>

Unpaid requests get 402 Payment Required with payment instructions; paid requests settle in USDC on Algorand via the GoPlausible facilitator and return JSON like:

Verifiable on-chain: first mainnet settlement — 3F2ATV3NCRVOI45IEL6OUKAWED3NQX246WJADESJB5CFR6LIXGCQ

{
  "target": "https://x402.example.com/api",
  "status": "pass",
  "score": 98.7,
  "detail": {
    "observations": 1439,
    "windowHours": 24,
    "uptimePct": 100,
    "correct402Pct": 100,
    "p50LatencyMs": 88,
    "p95LatencyMs": 127,
    "confidence": "history"
  }
}

Use it in your own code

A small TypeScript SDK wraps the full x402 pay-per-call handshake (402 → sign USDC payment → retry) so you don't have to implement it yourself:

import { getReliability } from 'hosannaith-client';

const result = await getReliability('https://some-x402-endpoint/api', {
  mnemonic: process.env.AVM_MNEMONIC!, // 25-word Algorand mnemonic, funded with USDC
});

console.log(result.score, result.detail.confidence);

See sdk/typescript/ for the client, a runnable example, and full usage docs.

Use it from any MCP agent (Model Context Protocol)

This repo also ships an MCP server in mcp/ — published to npm as hosannaith-mcp and listed in the official MCP Registry as io.github.cameron4316/hosannaith-mcp. It lets any Model Context Protocol client (Claude Desktop, Cursor, and other MCP agents) vet an x402 endpoint's reliability before paying it.

Built on the official MCP TypeScript SDK (@modelcontextprotocol/sdk), it exposes three MCP tools:

• get_hosannaith_info — free; explains the score shape and how to act on it.
• check_x402_reliability — paid; reliability score for one endpoint, settled as an x402 USDC micropayment on Algorand.
• check_x402_reliability_batch — paid; score up to 50 endpoints in a single call.

Add it to an MCP client's config:

{
  "mcpServers": {
    "hosannaith": {
      "command": "npx",
      "args": ["-y", "hosannaith-mcp"],
      "env": { "AVM_MNEMONIC": "<25-word Algorand mnemonic, funded with USDC>" }
    }
  }
}

See mcp/ for the MCP server, its tools, and full setup docs.

Architecture and vision

The architecture is deliberately pluggable: every paid product implements the Check contract (see src/checks/types.ts). Reliability ships first; a compliance/attestation product for tokenization — the trust layer institutions need to bring real-world assets on-chain — is planned as a second Check + one route entry, with no rewrite of the payment plumbing.

The monitor (pnpm monitor, run continuously on the production droplet) records one observation per target per interval, append-only, to data/observations.jsonl. That history compounds and cannot be reconstructed later — every score above is backed by real, continuous observation, not a synthetic estimate.

---

For developers

Everything below is setup/reference for running Hosannaith locally (defaults to testnet) or understanding the codebase — not required to use the live API above.

---

1. Install

pnpm install
# runtime deps (exact packages from the official Algorand tutorial):
pnpm add @x402/core @x402/avm @x402/hono @x402-avm/extensions hono @hono/node-server dotenv

2. Configure

cp .env.example .env

Then edit .env:

• AVM_ADDRESS — a testnet account funded with ALGO and opted in to testnet USDC.
• Leave NETWORK=testnet and the GoPlausible FACILITATOR_URL as-is for now.
• MONITOR_TARGETS already points at the Foundation's public example endpoint.

Testnet setup (accounts, faucets, USDC opt-in) follows the official tutorial: https://dev.algorand.co/resources/x402-on-algorand/

3. Run (two terminals)

pnpm monitor   # terminal 1 — starts collecting observations immediately
pnpm dev       # terminal 2 — starts the paid resource server on :4021

Sanity checks:

curl http://localhost:4021/health                 # -> {"ok":true,...}  (free)
curl -i "http://localhost:4021/reliability?target=https://x402.goplausible.xyz/examples/weather"
#  -> HTTP 402 Payment Required  (correct: it's a PAID route)

To pay and get the JSON back, point the tutorial's client at http://localhost:4021/reliability?target=... (client code: https://dev.algorand.co/resources/x402-on-algorand/#part-1-build-the-client).

---

File map

src/
  index.ts              Hono app + x402 wiring (edit sparingly)
  monitor.ts            Standalone monitor process (pnpm monitor)
  config.ts             Network/asset/facilitator config; testnet<->mainnet switch
  routes.config.ts      Paid routes + Bazaar discovery metadata  <-- add compliance route here
  checks/
    types.ts            The pluggable Check contract (shared by all products)
    registry.ts         Maps check id -> implementation
    reliability/
      monitor.ts        probe() + startMonitor()
      store.ts          Observation type + append-only JSONL store (swappable)
      score.ts          Turns observations into a 0-100 score
      index.ts          The reliability Check (reads store, computes score)
data/
  observations.jsonl    Append-only history (git-ignored; compounding)

Mainnet is live — the CAIP-2 override, explained accurately

src/config.ts's FACILITATOR_TESTNET_CAIP2 and MAINNET_CAIP2 are hardcoded, not imported from @x402/avm — and that's deliberate, not an oversight. Here's the real story:

@x402/avm's ALGORAND_TESTNET_CAIP2 / ALGORAND_MAINNET_CAIP2 exports are the spec-correct, truncated CAIP-2 form (per the Algorand CAIP-2 namespace profile; fixed upstream in x402-foundation/x402 issue #2904 / PR #2931). The package is not the problem. The live GoPlausible facilitator (facilitator.goplausible.xyz) runs GoPlausible/x402-avm, a fork hundreds of commits behind upstream that predates that fix — so its /supported endpoint still advertises the legacy, non-compliant full-genesis-hash form, on both testnet and mainnet. This server hardcodes the values the facilitator actually expects, verified live via curl https://facilitator.goplausible.xyz/supported, not guessed and not the package constant.

If GoPlausible syncs their fork to the upstream fix, both constants must be reverted back to importing from @x402/avm — see the comments at each constant in src/config.ts for the full reasoning. A tracking report was filed upstream against x402-foundation/x402 (GoPlausible's own fork has issue creation restricted, so that wasn't an option).

To run this server against mainnet yourself: set NETWORK=mainnet and AVM_ADDRESS to a fixed payTo address opted in to mainnet USDC (ASA 31566704, already set in src/config.ts). The tag field in routes.config.ts's extra attributes activity to the Algorand Global x402 Challenge.

Notes

• Tracks x402 protocol 2.26.0 (package.json pins ^2.26.0 for @x402/core, @x402/avm, and @x402/hono; the Algorand discovery/Bazaar package @x402-avm/extensions versions separately, currently ^2.6.1 — run pnpm ls for exact resolved versions).
• Run pnpm typecheck after pnpm install to catch any API drift if you bump dependency versions.