"Signal" matching MCP connectors:

DePIN network telemetry with the source, as_of time and an upstream verify URL on every value.

SignalHarness.aiA

ai.signalharness

Remote MCP server exposing 330 production AI-agent services for web/data processing, validation, AI utilities, blockchain/crypto utilities, and x402 pay-per-use access.

Machine-native tools for autonomous agents with free routing and x402 USDC pay-per-call.

Rio Grande Valley, Texas construction data: free catalog, samples and series; paid calls via x402

Pay-per-call US brand evidence and signal workflows with free MCP discovery and x402 payments.

Score two AI outputs, get exact failure reasons, and issue a $0.01 USDC receipt via x402.

Free tools: x402 endpoint directory + probe, on-chain x402 demand signal, sudoku, API pricing.