Yes, Base Facts is free to use.

How do I install Base Facts?

Base Facts is a local plugin. Install it using npm package: base-facts-mcp and add the generated configuration snippet to your AI app's MCP config file. Then restart your AI app.

Is Base Facts safe to use?

Yes. Base Facts passed MCP Marketplace's automated security scan with a score of 10/10 (low risk). Every server on MCP Marketplace is security-scanned before it's listed; see the full security report on this page for the findings and permissions.

What credentials does Base Facts need?

Base Facts requires the following credentials or environment variables: X402_PRIVATE_KEY, SESSION_BUDGET_USD. You can find setup instructions on the server detail page.

What AI apps work with Base Facts?

Base Facts uses the Model Context Protocol (MCP) and works with any MCP-compatible AI app, including Claude, ChatGPT / Codex, Gemini, Copilot, Cursor, and more.

Back to Browse

Base Facts MCP Server

by Yankiifr

Developer ToolsLow Risk10.0MCP RegistryLocal

Free

Server data from the Official MCP Registry

Base token checks for agents: simulated buy and sell, taxes, honeypots. Pay per call in USDC (x402).

About

Base token checks for agents: simulated buy and sell, taxes, honeypots. Pay per call in USDC (x402).

Security Report

10.0

Low Risk10.0Low Risk

Valid MCP server (3 strong, 3 medium validity signals). No known CVEs in dependencies. Package registry verified. Imported from the Official MCP Registry.

5 files analyzed · 1 issue found

Security scores are indicators to help you make informed decisions, not guarantees. Always review permissions before connecting any MCP server.

Permissions Required

This plugin requests these system permissions. Most are normal for its category.

file_system

Check that this permission is expected for this type of plugin.

env_vars

Check that this permission is expected for this type of plugin.

What You'll Need

Set these up before or after installing:

Private key of a small x402 payer wallet holding a little USDC on Base (pays $0.002-$0.01 per call). Alternative: X402_PAYER_FILE.Required

Environment variable: X402_PRIVATE_KEY

Stop paying once this much was spent in the session (default 1).Optional

Environment variable: SESSION_BUDGET_USD

How to Install

Add this to your MCP configuration file:

{
  "mcpServers": {
    "io-github-yankiifr-base-facts-mcp": {
      "env": {
        "X402_PRIVATE_KEY": "your-x402-private-key-here",
        "SESSION_BUDGET_USD": "your-session-budget-usd-here"
      },
      "args": [
        "-y",
        "base-facts-mcp"
      ],
      "command": "npx"
    }
  }
}

Documentation

View on GitHub

From the project's GitHub README.

base-facts-mcp

An MCP server for AI agents that trade or move money on Base. Each tool calls Base Token Facts and pays for the call itself in USDC over x402, from a small wallet you control. Every answer is read at one block and says which.

Tool	Price	Answers
`base_token_verdict`	$0.01	Before buying a token: risk level, score and flags (proxy, mint, pause, blacklist, owner, DEX liquidity), each with its on-chain fact
`base_token_sellcheck`	$0.005	Honeypot and tax check: simulates a small buy and immediate sell on the deepest pool, returns buy/sell tax, round-trip loss
`base_token_sellcheck_size`	$0.01	The same check at your trade size (`amountEth`, 0.001 to 10 ETH): tax, round-trip loss, buy price impact and a depth warning when the size is larger than the pool can absorb
`base_token_facts`	$0.005	ERC20 metadata, owner, proxy and implementation, admin selectors in the bytecode
`base_wallet_snapshot`	$0.002	ETH and USDC balances, nonce, contract or not
`base_gas`	$0.001	Base fee, priority fee, gas price
`base_tx_summary`	$0.003	Status, fee and decoded ERC20 transfers of a transaction
`basename_resolve`	$0.002	`name.base.eth` to address, or address to its verified primary Basename
`base_facts_budget`	free	What this session has spent

Facts and heuristics, not financial advice. API docs and live revenue counter: https://base-facts.yankii.fr and https://base-facts.yankii.fr/stats

Setup

Make a dedicated wallet and put a little USDC on it, on the Base network (1 USDC pays for 100 verdicts). No ETH is needed: the x402 facilitator pays the gas. Never use your main wallet.
Add the server to your MCP client, for example claude_desktop_config.json:

{
  "mcpServers": {
    "base-facts": {
      "command": "npx",
      "args": ["-y", "base-facts-mcp"],
      "env": {
        "X402_PAYER_FILE": "/path/to/payer.json",
        "MAX_PRICE_USD": "0.02",
        "SESSION_BUDGET_USD": "1"
      }
    }
  }
}

payer.json is { "privateKey": "0x..." }; X402_PRIVATE_KEY works too. Without either, the server uses ~/.base-facts-mcp/payer.json when it exists.

Every setting also exists as an option, for hosts that pass only command and args (Preste): --payer-file <path>, --max-price <usd>, --budget <usd>, --api <url>. See integrations/preste/ for the Preste config and skill.

Spending safety

MAX_PRICE_USD (default 0.02): the client refuses to sign any single payment above it.
SESSION_BUDGET_USD (default 1): once reached, the client stops signing until restarted.
BASE_FACTS_PAY_TO (default: the official address when using the default API): the only recipient the client will sign for. Required with a custom BASE_FACTS_URL; without it nothing is signed. The client also signs only Base USDC (0x8335…2913).
Only USDC on Base (eip155:8453) is ever signed.
A refused or failed call (4xx/5xx) cancels the settlement: you are not charged, and the tool says charged: false with the reason (for example not enough USDC).
Paid calls run one at a time so the budget count stays exact.

Development

npm test drives the server over stdio like a real client, with empty wallets: no USDC is spent.

Reviews

No reviews yet

Be the first to review this server!

4.8

Local

mcp-creator-python

Free

by mcp-marketplace · Developer Tools

Create, build, and publish Python MCP servers to PyPI — conversationally.

Stars

145

Installs