Median MCP server endpoint

JSON-RPC 2.0 Streamable HTTP endpoint. Default customer API keys and OAuth tokens expose only read tools. A separately scoped forecast:write API key may also expose the Forecast sandbox staging tool, which never changes the live forecast. Tool names and input schemas are documented in openapi/mcp-tools.json. Limits are 30 tool calls per minute and 300 per hour per API key or OAuth user-company identity, with an additional 20 calls per minute for each bulk-read tool. Every tool call in a JSON-RPC batch consumes its own budget. If any item exceeds a limit, the full batch is rejected atomically with HTTP 429, Retry-After, and one JSON-RPC error per request item. A batch may contain at most 20 items; a longer batch is rejected with HTTP 400 and a single JSON-RPC -32600 error before any budget is consumed.