# Base Token Facts [Health: Active]

**Category:** 💰 Finance & Fintech  
**Repository:** https://github.com/yankiifr/base-facts-mcp  
**GitHub Stars:** 0  
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**Directory Page:** https://allmcps.com/mcp/base-token-facts

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

## Claude Desktop Quick Installation
Install path detected from listing signals. Uses `npx` (confidence: high):

```json
"mcpServers": {
  "base-token-facts": {
    "command": "npx",
    "args": ["-y","base-facts-mcp"],
    "env": {
      "X402_PAYER_FILE": "",
      "X402_PRIVATE_KEY": "",
      "MAX_PRICE_USD": "",
      "SESSION_BUDGET_USD": "",
      "BASE_FACTS_PAY_TO": "",
      "BASE_FACTS_URL": ""
    }
  }
}
```

**Requires environment variables:** `X402_PAYER_FILE`, `X402_PRIVATE_KEY`, `MAX_PRICE_USD`, `SESSION_BUDGET_USD`, `BASE_FACTS_PAY_TO`, `BASE_FACTS_URL` — the values above are empty placeholders; fill in real credentials before running (see the repository for what each one is for).

## Documentation

## What Base Token Facts does

The Base Token Facts MCP server exposes paid, on-chain checks for agents that trade or move money on Base. It connects to the Base Token Facts API and uses x402 to settle each request in USDC from a dedicated payer wallet. Responses identify the block used for the answer, which helps callers understand the data’s point in time.

Token-oriented tools include a verdict with a risk level, score, and checks for proxy, mint, pause, blacklist, owner, and DEX liquidity behavior. Sell checks simulate a small buy followed by an immediate sell on the deepest pool, returning buy and sell taxes plus the round-trip loss. A batch tool performs the same simulation for up to 10 tokens in one paid request. A size-aware version accepts a trade amount from 0.001 to 10 ETH and adds price-impact and pool-depth warnings.

Other tools return ERC20 metadata and contract details, wallet ETH and USDC balances, nonce and contract status, Base fee information, transaction status and fee data, decoded ERC20 transfers, and Basename mappings. The budget tool reports session spending.

## How it works

The server runs as an MCP process and forwards tool calls to Base Token Facts. Paid calls use Base USDC on chain ID 8453. The client checks the configured per-call maximum, session budget, and approved recipient before signing. Each tool also has a published price ceiling, so a request cannot exceed that tool’s listed price even if the general maximum is higher.

Payments run one at a time so budget accounting remains exact. If a request fails with a 4xx or 5xx response, settlement is canceled and the tool reports that it was not charged. If the response is lost after signing, the amount may have settled and is counted toward the session budget.

## Setup and configuration

Create a dedicated payer wallet and place Base USDC in it. The README states that 1 USDC covers 100 verdict calls and that no ETH is needed because the x402 facilitator pays gas. Configure `X402_PAYER_FILE` with a JSON file containing a private key, or use `X402_PRIVATE_KEY`. If neither is set, the server checks `~/.base-facts-mcp/payer.json`.

The default launch uses `npx -y base-facts-mcp`. Set `MAX_PRICE_USD` to cap one payment and `SESSION_BUDGET_USD` to cap total signed payments after restart. For a custom API URL, configure `BASE_FACTS_URL` and also set `BASE_FACTS_PAY_TO`; otherwise the client will not sign. Hosts that pass only command arguments can use the equivalent payer-file, max-price, budget, and API options.

## Tools and capabilities

- `base_token_verdict`: reports token risk signals and their on-chain facts.
- `base_token_sellcheck`: simulates a small buy and sell for taxes and honeypot behavior.
- `base_token_batch_screen`: screens up to 10 tokens in one call.
- `base_token_sellcheck_size`: evaluates a specified ETH trade size and liquidity depth.
- `base_token_facts`: returns ERC20 and contract implementation details.
- `base_wallet_snapshot`, `base_gas`, and `base_tx_summary`: inspect wallet, fee, and transaction data.
- `basename_resolve` and `base_facts_budget`: resolve Basenames and track spending.

## Limitations and notes

Base Token Facts provides facts and heuristics, not financial advice. Calls consume Base USDC, and the payer wallet should not be a main wallet. The checks are snapshots at a reported block, not guarantees about future token behavior or execution outcomes. Custom API use requires an explicitly approved payment recipient. The Base Token Facts MCP server supports stdio-based MCP clients, but the README does not document client-specific behavior beyond the Claude Desktop example.

_Full upstream README: https://allmcps.com/mcp/base-token-facts/readme_