Base Token Facts

io.github.yankiifrv0.2.1Updated Oct 6, 2026

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

VerifiedSTDIODesktop onlyFinance Security & Monitoring

Overview

AI-generated overview

Lets an assistant check Base tokens before trading: risk verdicts, honeypot and tax simulation, wallet and gas facts, paid per call in USDC.

What it does: It exposes read-only tools that query the Base Token Facts service: base_token_verdict returns a risk level, score and flags such as proxy, mint, pause, blacklist, owner and DEX liquidity; base_token_sellcheck simulates a small buy and immediate sell on the deepest pool to report buy/sell tax and round-trip loss; base_token_facts returns ERC20 metadata, owner, proxy and implementation; base_wallet_snapshot, base_gas, base_tx_summary and basename_resolve cover balances, fees, transaction decoding and Basename lookups. base_facts_budget reports what the session has spent. Each paid call is settled in USDC over x402 from a wallet you control, and answers are read at one block.
When to use it: Use it when an assistant is about to buy, sell or move tokens on Base and needs on-chain facts and honeypot or tax checks first. It is aimed at agent workflows that trade or move money on Base, not at general blockchain browsing.
Requirements: Runs locally over stdio, typically via npx base-facts-mcp, so Node.js is needed. It requires a dedicated Base wallet holding a little USDC, supplied through X402_PRIVATE_KEY or a payer file (X402_PAYER_FILE, or ~/.base-facts-mcp/payer.json by default). Optional settings include MAX_PRICE_USD and SESSION_BUDGET_USD. Network access to the Base Token Facts API is required; no account or login is declared.

Before you install

The server signs real USDC payments on Base, $0.001 to $0.01 per call, so a funded wallet is at risk; use a dedicated wallet and never a main one. X402_PRIVATE_KEY and the payer file hold a private key that must be protected. MAX_PRICE_USD and SESSION_BUDGET_USD cap per-call and per-session spending, and failed calls are not charged. Output is facts and heuristics, not financial advice.

Installation

In SourceWeft

Open Base Token Facts in the dashboard and add it to a workspace.
Enable the server for the chats that should use its tools.

Desktop only via STDIO. STDIO servers start a local process, so they need the SourceWeft desktop host.

Other MCP clients

Follow the launch instructions in the repository.

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_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:

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"      }    }  }}

{  "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.
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.

Source: README.md at commit 9ad460f

Tools

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Version history

v0.2.1LatestOct 6, 2026