PlainText Wallet Approval Checker MCP server

PlainText — wallet approval translator

A small Node.js app that looks up a wallet's token/NFT approvals via the GoPlus Security API and asks Claude to explain them in plain language.

Project structure

plaintext-wallet/
├── server.js          Express backend (GoPlus + Anthropic calls)
├── package.json
├── render.yaml         Render deploy config (optional, see below)
├── .env.example         Copy to .env for local dev
└── public/
    └── index.html      Frontend (wallet check + demo scenarios)

1. Run it locally first

cd plaintext-wallet
npm install
cp .env.example .env
# edit .env and paste your ANTHROPIC_API_KEY
npm start

Open http://localhost:3000 — try the "Try a sample" tab first (no API keys needed besides Anthropic), then "Check a wallet" with a real address once you're happy it works.

2. Deploy to Render

Option A — one-click via render.yaml (Blueprint)

Render reads render.yaml automatically and creates the web service.

1. Push this folder to a new GitHub repo.
2. In the Render dashboard: New + → Blueprint → select your repo.

1. When prompted, fill in the environment variables:

free 30 calls/minute limit (see console.gopluslabs.io)

• ANTHROPICAPIKEY — required, from console.anthropic.com
• GOPLUSACCESSTOKEN — optional, only needed if you outgrow GoPlus's

1. Click Apply — Render builds and deploys automatically.

Option B — manual web service (no render.yaml needed)

1. Push this folder to a GitHub repo.
2. Render dashboard → New + → Web Service → connect your repo.
3. Settings:

• Environment: Node
• Build Command: npm install
• Start Command: npm start
• Instance Type: Free (fine for a prototype)

GOPLUSACCESSTOKEN).

1. Under Environment Variables, add ANTHROPICAPIKEY (and optionally

URL once the build finishes.

1. Click Create Web Service. Render gives you a https://.onrender.com

Render's free tier spins the service down after inactivity — the first request after idling will take ~30-50 seconds to wake up. That's normal and fine for a prototype you're sharing for feedback.

Notes on the GoPlus integration

under https://api.gopluslabs.io/api/v2/.... This is documented but the GoPlus docs site is JS-rendered, so before you rely on this in front of real users, do one manual test call (e.g. with curl) against a wallet you control, and compare the actual JSON shape to what server.js expects — field names occasionally shift between GoPlus API versions.

• The wallet check calls tokenapprovalsecurity or nft721approvalsecurity

testing, but rate-limit errors will surface as a plain error message in the UI if you exceed it.

• The free GoPlus tier is capped at 30 calls/minute — plenty for early

round trip. If you later add accounts, saved wallets, or history, update this note (and your own privacy policy) accordingly.

• No user data is stored anywhere in this app — every check is a stateless

Costs to expect

tier ($7/month "Starter") removes the spin-down if this gets real usage.

• Render free tier: $0/month, with the cold-start behavior above. A paid

single explanation call is small (well under 1K tokens), so cost per check will be a fraction of a cent — but keep an eye on your usage dashboard if this gets shared widely, since there's no rate limiting built into this prototype yet.

• Anthropic API: pay-per-use, billed to whatever key you provide. A