Token Safety Check

token-safety-check

Is this token safe? A rug check for any token on Base, Ethereum, Arbitrum, Optimism, Polygon or Solana, for AI agents and scripts. Each check returns:

• a 0–100 risk score and level (low, medium, high, critical) with plain-language reasons:
• who can mint, freeze, blacklist, pause or change fees
• upgradeable contract code
• Token-2022 permanent delegates, transfer fees and hooks
• holder concentration
• thin or missing liquidity
• a deployer whose earlier tokens lost their liquidity, or who launches tokens in bulk
• the facts behind the score: owner, authorities, supply, top holders, pools, and the deployer's launch record when we saw the token launch;
• USD price and liquidity;
• a fingerprint. Pass it back as since and the next check tells you what changed: new risks, authority changes, liquidity or price moves. That makes it easy to monitor tokens on a schedule.

A verdict call turns the same facts into a grade (CLEAN, MID, SKETCHY or RUGGY), a one-liner, a short take and a link to a share card, for chat replies and quests.

A watchlist call re-checks up to 5 tokens at once for the same $0.01, returning a compact entry per token and one-line alerts for whatever changed since your last call.

Checks, verdicts and watchlist calls cost $0.01 each in USDC on Base, paid automatically with x402 from a wallet you control. There's no account or API key. Errors and invalid input are never charged, and a spending cap stops any call priced above your limit (default $0.05).

The score is rules-based and is not investment advice. Powers count for less on tokens with deep liquidity, where they're usually a large issuer's compliance controls (USDC can freeze and mint, for example).

Use it from Claude Desktop, Cursor or any MCP client

Create a new wallet just for this and send it a little USDC on Base: $1 covers 100 checks. Then add to your MCP config (for Claude Desktop, that's claude_desktop_config.json):

{

"mcpServers": { "token-safety-check": { "command": "npx", "args": ["-y", "token-safety-check"], "env": { "X402_PRIVATE_KEY": "0x " } } } }

The server has three tools:

• check_token_safety (address, optional chain and since): the full check for one token.
• token_verdict (address, optional chain): a grade, one-liner, short take and share-card link.
• watch_tokens (tokens: up to 5 of { address, chain?, since? }): re-checks them all in one paid call and, given each token's earlier fingerprint, reports what changed with one-line alerts.

Optional environment variables:

• TOKEN_SAFETY_MAX_USD: per-check spending cap, default 0.05.
• TOKEN_SAFETY_ENDPOINT: point at another deployment.

Use it from code

npm install token-safety-check

import { createTokenSafetyClient } from "token-safety-check";

const client = createTokenSafetyClient({ privateKey: process.env.X402_PRIVATE_KEY as 0x${string} });

const first = await client.checkToken({ chain: "base", address: "0x4ed4E862860beD51a9570b96d89aF5E1B0Efefed" }); console.log(first.risk.score, first.risk.level, first.risk.summary); // 15 low Low risk: the owner can pause all transfers; ownership is not renounced.

// Later: what changed since then? const later = await client.checkToken({ address: first.address, chain: "base", since: first.watch.fingerprint }); if (later.watch.changes?.anythingChanged) console.log(later.watch.changes);

A verdict for a chat reply

const v = await client.verdict({ address: "0xe468f13905669748bf312611b9ebcc8ccc6db5d9" });

console.log(v.grade, v.oneLiner); // SKETCHY Liquidity: two coins and a prayer console.log(v.take, v.card); // "$KTI: 60/100 risk. ..." and a signed share-card link // Pass requestKey (8-128 letters, digits or _.:-) and a retry with the same key is never charged twice.

Watch what you hold

let list = [

{ chain: "base", address: "0x4ed4E862860beD51a9570b96d89aF5E1B0Efefed" }, { chain: "solana", address: "JUPyiwrYJFskUPiHa7hkeR8VUtAeFoSYbKedZNsDvCN" }, ] as const; let fingerprints: (string | undefined)[] = [];

// Every hour (or however often): one $0.01 call for the whole list. const w = await client.watchlist(list.map((t, i) => ({ ...t, since: fingerprints[i] }))); for (const alert of w.alerts) console.log(alert); // e.g. "PEPINA (eth): risk 0 -> 30 (medium); liquidity -99.99%" fingerprints = w.tokens.map((t) => t.fingerprint);

Use it in the Vercel AI SDK or Mastra

token-safety-check/ai gives three ready tools (checkTokenSafety, tokenVerdict, watchTokens), plain { description, inputSchema, execute } objects that both take as tools:

import { generateText } from "ai";

import { createTokenSafetyClient } from "token-safety-check"; import { tokenSafetyTools } from "token-safety-check/ai";

const tools = tokenSafetyTools(createTokenSafetyClient({ privateKey: process.env.X402_PRIVATE_KEY as 0x${string} })); const { text } = await generateText({ model, tools, prompt: "Is 0x4ed4E862860beD51a9570b96d89aF5E1B0Efefed on Base safe to buy?" });

Use it in ElizaOS

token-safety-check/eliza is an ElizaOS 1.x plugin with one action, CHECK_TOKEN_SAFETY. When a message names a token address ("is 0x… on Base safe?", "rug check "), the agent replies with the verdict and a share-card link.

import { tokenSafetyPlugin } from "token-safety-check/eliza";

export const character = { name: "trader", plugins: [tokenSafetyPlugin], settings: { secrets: { TOKEN_SAFETY_PRIVATE_KEY: process.env.TOKEN_SAFETY_PRIVATE_KEY } }, };

Settings: TOKEN_SAFETY_PRIVATE_KEY (a dedicated wallet with a little USDC on Base; falls back to X402_PRIVATE_KEY), optional TOKEN_SAFETY_MAX_USD (default 0.05) and TOKEN_SAFETY_ENDPOINT.

Use it in Coinbase AgentKit

import { customActionProvider } from "@coinbase/agentkit";

import { z } from "zod"; import { createTokenSafetyClient } from "token-safety-check";

const safety = createTokenSafetyClient({ privateKey: process.env.X402_PRIVATE_KEY as 0x${string} });

export const tokenSafety = customActionProvider({ name: "check_token_safety", description: "Rug check a token on Base, Ethereum, Arbitrum, Optimism, Polygon or Solana: 0-100 risk score with reasons.", schema: z.object({ address: z.string().describe("Token contract or Solana mint address"), chain: z.enum(["base", "eth", "arbitrum", "optimism", "polygon", "solana"]).optional(), }), invoke: async (args) => JSON.stringify(await safety.checkToken(args)), }); // Add tokenSafety to the actionProviders you pass to AgentKit.from(...).

Use it in LangChain (JS)

import { tool } from "@langchain/core/tools";

import { z } from "zod"; import { createTokenSafetyClient } from "token-safety-check";

const safety = createTokenSafetyClient({ privateKey: process.env.X402_PRIVATE_KEY as 0x${string} });

export const checkTokenSafety = tool(async (args) => JSON.stringify(await safety.checkToken(args)), { name: "check_token_safety", description: "Rug check a token on Base, Ethereum, Arbitrum, Optimism, Polygon or Solana: 0-100 risk score with reasons.", schema: z.object({ address: z.string(), chain: z.enum(["base", "eth", "arbitrum", "optimism", "polygon", "solana"]).optional(), }), });

Example output (trimmed)

{

"address": "0x4ed4E862860beD51a9570b96d89aF5E1B0Efefed", "chain": "base", "name": "Degen", "symbol": "DEGEN", "risk": { "score": 15, "level": "low", "reasons": [ { "code": "can-pause", "points": 10, "text": "The owner can pause all transfers." }, { "code": "owner-not-renounced", "points": 5, "text": "Ownership is not renounced." } ], "summary": "Low risk: the owner can pause all transfers; ownership is not renounced." }, "market": { "dex": "uniswap-v3", "pairedWith": "WETH", "priceUsd": 0.000963, "quoteSideLiquidityUsd": 134000 }, "watch": { "fingerprint": "eyJzIjoxNSwi…", "changes": null } }

Without this package

Both are plain x402 endpoints, so any x402 client can call them directly: GET https://onchaincheck.dev/token?chain= &address= [&since= ] and GET https://onchaincheck.dev/watchlist?tokens= : ,...[&since= ,...]. It's also listed in the x402 Bazaar.

Safety notes

• Use a dedicated wallet with a small balance. The key never leaves your machine; it only signs USDC payments of the quoted price.
• Each check's price is read from the server's payment request before paying, and anything above maxUsdPerCheck / TOKEN_SAFETY_MAX_USD is refused.

MIT licensed.