// ---------------------------------------------------------------------------// Extract the HTTP status from an MCP SDK transport error. The SDK surfaces// transport failures two ways: a `StreamableHTTPError` subclass carrying a// numeric `code`, and an SSE POST failure whose message embeds `(HTTP nnn)`.// Shared by the invoke path (classifies tool-call failures) and the connect// path (so a 401/403 during the handshake reaches the liveness health check).// --------------------------------------------------------------------------- import { Option, Schema } from "effect"; import { StreamableHTTPError } from "@modelcontextprotocol/sdk/client/streamableHttp.js"; const SsePostErrorCause = Schema.Struct({ message: Schema.String });const decodeSsePostErrorCause = Schema.decodeUnknownOption(SsePostErrorCause); // Matches the SDK's SSEClientTransport POST-failure message (sse.js); re-verify// on SDK bumps. A format drift just yields undefined (generic error, no crash).const statusFromSsePostError = (cause: unknown): number | undefined =>  Option.match(decodeSsePostErrorCause(cause), {    onNone: () => undefined,    onSome: ({ message }) => {      const match = /^Error POSTing to endpoint \(HTTP ([1-5][0-9]{2})\):/.exec(message);      if (!match) return undefined;      return Number(match[1]);    },  }); const statusFromStreamableHttpError = (cause: unknown): number | undefined => {  // oxlint-disable-next-line executor/no-instanceof-tagged-error -- boundary: MCP SDK exposes transport HTTP failures as this Error subclass; protocol errors can carry the same numeric code  if (!(cause instanceof StreamableHTTPError)) return undefined;  const code = cause.code;  return code !== undefined && code >= 100 && code <= 599 ? code : undefined;}; export const httpStatusFromCause = (cause: unknown): number | undefined =>  statusFromStreamableHttpError(cause) ?? statusFromSsePostError(cause);