mcp-gauge is an MCP (Model Context Protocol) server that provides AI agents with verifiable, screening-grade signals from GAUGE. Its positioning is: check official facts before an AI agent acts.
Purpose
This tool is aimed at AI agents that need to make judgments based on external facts, providing more than 180 signals from sources such as USGS, NOAA, SEC EDGAR, and EPA. The coverage areas listed in the introduction include: environment (such as floods, air quality, drought), agriculture (such as crops), power, shipping, and SEC filings (FRED and SEC EDGAR, etc.).
Main Capabilities
- Provides verifiable, screening-grade signals, with each response including multi-source cross-validation.
- Each paid record carries a record_hash (canonical SHA-256).
- Daily Merkle roots are anchored to Bitcoin via OpenTimestamps, generating tamper-proof receipts.
- Supports both free tools and paid tools. Free tools require only a wallet to use; paid tools are divided into single-source verification and 3-source cross-validation bundles.
- For paid calls, the GAUGE server returns an x402 payment challenge, and the MCP client automatically pays in USDC on Base and retries the request, with the receipt included in each response.
How to Use
Add the configuration in ~/Library/Application Support/Claude/claude_desktop_config.json on macOS or %APPDATA%\Claude\claude_desktop_config.json on Windows; it can also be added in .cursor/mcp.json in the project root directory (or the global configuration).
Any MCP client that supports stdio transport can use it. The command is: npx -y mcp-gauge-x402, and paid tools require setting EVM_PRIVATE_KEY in the environment variables.
It can also be installed from GitHub (no npm account required).
Verification Mechanism
Paid records can be re-verified through the gauge_anchor tool (free) or the GAUGE API's POST /verify or /proof/:record_hash. Users can also download the OpenTimestamps proof bytes and verify them through the official ots CLI. According to the description, this stamped proof records that the record set existed no later than stamped_at, rather than proving that it was collected on that data day.
Payment and Environment Variables
- Network: Base mainnet (Coinbase L2).
- Payment: USDC is used, and x402 uses EIP-3009 (gasless USDC transfers without needing ETH).
- The private key never leaves the user's machine; it is handled locally by x402-fetch and only the signed authorization is sent.
- It is recommended to use a dedicated one-time wallet and keep a small USDC balance; do not use your main wallet.
- If you use your own x402 client to call the API, set maxValue to at least $0.25; the default $0.10 will cause the client to locally reject the bundle tool.
- Pricing is set by the live x402 challenge; use gauge_preview to view the current pricing.
- If no private key is set, all 5 free tools can still be used; paid tools will be listed, but calling them returns an error.
Limitations and Boundaries
- When data is unavailable, the tool fails honestly and does not charge; you pay only when you get a result.
- OpenTimestamps anchoring proves that the record set existed no later than the stamping time, not that the data was collected on the day it was gathered.
- License is MIT · AEML-DS Vanished-Data Exchange.
Other Information
Website: truthbear.co; front desk: gauge-frontdesk.zeabur.app; API discovery:https://api.truthbear.co/.well-known/x402 and /llms.txt; Smithery: smithery.ai/servers/a98741263/mcp-gauge; GitHub: CHANGCHINFU/mcp-gauge.
