mcp-gauge — MCP server for GAUGE (verifiable signals, pay-per-call in USDC via x402)

Give any MCP host (Claude Desktop, Cursor, MCP-compatible agents) access to GAUGE's verifiable, screening-level signals across many domains (weather, drought, agriculture, power grid, shipping, regulatory filings, and more) — and let the agent pay per call in USDC on Base via x402 (EIP-3009 gasless, no API key, no signup).

Pure description — official-source facts (USGS / NOAA / EPA / CAMS / ERA5 / FRED / Open-Meteo Marine / SEC EDGAR) + back-testable statistics + record_hash, with daily Merkle roots stamped via OpenTimestamps to Bitcoin — the stamp proves the record set existed no later than its stamped_at; it is not evidence about the data day itself. The agent decides. Payment settles directly to the provider wallet.

Backed by the GAUGE service at https://api.truthbear.co. (The service also still answers on its previous host https://aeml-x402.zeabur.app; api.truthbear.co is the canonical URL and is what every 402 challenge advertises as the resource.)

Part of Truth Bear 🐻 — GAUGE is the data engine behind Truth Bear, the natural-language front desk for AI agents and SMBs. Ask in plain language, get the official fact + its source + a verifiable record_hash — no prediction, no advice, the rest is your call. An analyst, not a commander. Front desk: https://gauge-frontdesk.zeabur.app · discovery: /.well-known/x402, /llms.txt.

Why MCP + x402

• Discovery is free and open (MCP): any MCP host lists these tools with zero setup.

• Payment is crypto (x402): the agent pays USDC only when it calls a paid tool.

• Free tools (gauge_catalog, gauge_preview, gauge_sample, gauge_river_free) need no wallet — try before you buy.

Related MCP server: x402-agent-data

Tools

Every figure above is regenerated from the live 402 quote. The 402 challenge the endpoint returns is always authoritative. If you drive the API with your own x402 client rather than this server, set its maxValue to at least $0.25 — the common default of $0.10 makes your client reject the bundle tools locally, before the request is ever sent. gauge_preview returns the current menu for free.

130+ signals (and growing) across hydrology, air quality, precipitation, agriculture, power grid, shipping and regulatory filing — with global coverage (US plus Argentina, Brazil, China, India, Ukraine, EU and more). Check the live set anytime via the free gauge_catalog tool.

Install & configure

Requires Node 18+. The MCP host runs the server over stdio. Install straight from GitHub — no npm account, no signup (the built dist/ is committed):

npx -y github:CHANGCHINFU/mcp-gauge

Claude Desktop

Add to claude_desktop_config.json (macOS: ~/Library/Application Support/Claude/, Windows: %APPDATA%\Claude\):

{
  "mcpServers": {
    "gauge": {
      "command": "npx",
      "args": ["-y", "github:CHANGCHINFU/mcp-gauge"],
      "env": {
        "EVM_PRIVATE_KEY": "0xYOUR_BASE_WALLET_KEY_WITH_A_LITTLE_USDC"
      }
    }
  }
}

Omit EVM_PRIVATE_KEY to use free tools only (catalog / preview / sample / river).

Cursor / other MCP hosts / Claude Code

• Claude Code: claude mcp add gauge -- npx -y github:CHANGCHINFU/mcp-gauge (add --env EVM_PRIVATE_KEY=0x… for paid tools).

• Cursor / others: command npx -y github:CHANGCHINFU/mcp-gauge, transport stdio, optional EVM_PRIVATE_KEY env.

From source

git clone https://github.com/CHANGCHINFU/mcp-gauge && cd mcp-gauge
npm install && npm run build
node dist/index.js        # stdio

Once published to npm the package name is mcp-gauge-x402 (npx -y mcp-gauge-x402); until then use the GitHub form above.

Config (env)

Handle the private key like any hot-wallet secret; fund it with a small USDC balance only.

Verify (zero-trust)

Every paid record carries record_hash (canonical sha256). Daily Merkle roots are stamped via OpenTimestamps to Bitcoin: the stamp proves the record set existed no later than its stamped_at — it is NOT evidence about the data day itself. Re-check via POST /verify or /proof/:record_hash at the GAUGE service; see /gauge/anchor for the day roots and attestation bytes (verify them with the official ots tool).

Distribution (maintainers)

• GitHub install (primary, no npm account): users run npx -y github:CHANGCHINFU/mcp-gauge.

• awesome-mcp-servers: submit a PR to a curated MCP server list for discoverability (no npm needed).

• MCP Registry (optional, needs npm): publish mcp-gauge-x402 to npm, then server.json is ready for the MCP publisher:

  npm publish
  mcp-publisher login github
  mcp-publisher publish

MIT · AEML-DS Vanished-Data Exchange