MCP server (streamable HTTP, stateless) — the API as agent tools

Model Context Protocol endpoint: JSON-RPC 2.0 over POST, plain-JSON responses, no sessions, no SSE. Four tools — search_datasets, get_table, tariff_lookup, resolve_data — each proxied to the public endpoint it names, so metering, licensing gates and x402 behave exactly as over plain HTTP. Pass an API key as x-api-key; anonymous callers get anonymous quotas. Point any MCP-capable client at https://api.stackdata.io/mcp.