From 8a20f7711ac70639d88f48a785f0fdc59a38a9f7 Mon Sep 17 00:00:00 2001
From: Justin Spahr-Summers <justin@anthropic.com>
Date: Fri, 24 Jan 2025 11:27:40 +0000
Subject: [PATCH] Use new `SseError` class from SDK

---
 server/src/errors.ts | 11 -----------
 server/src/index.ts  |  5 ++---
 2 files changed, 2 insertions(+), 14 deletions(-)
 delete mode 100644 server/src/errors.ts

diff --git a/server/src/errors.ts b/server/src/errors.ts
deleted file mode 100644
index eba1d40..0000000
--- a/server/src/errors.ts
+++ /dev/null
@@ -1,11 +0,0 @@
-export interface SseError extends Error {
-  code: number;
-}
-
-export function isSseError(error: unknown): error is SseError {
-  if (!(error instanceof Error)) {
-    return false;
-  }
-
-  return "code" in error && typeof error.code === "number";
-}
diff --git a/server/src/index.ts b/server/src/index.ts
index 1eaa7ae..1428e80 100644
--- a/server/src/index.ts
+++ b/server/src/index.ts
@@ -4,7 +4,7 @@ import cors from "cors";
 import { parseArgs } from "node:util";
 import { parse as shellParseArgs } from "shell-quote";
 
-import { SSEClientTransport } from "@modelcontextprotocol/sdk/client/sse.js";
+import { SSEClientTransport, SseError } from "@modelcontextprotocol/sdk/client/sse.js";
 import {
   StdioClientTransport,
   getDefaultEnvironment,
@@ -12,7 +12,6 @@ import {
 import { SSEServerTransport } from "@modelcontextprotocol/sdk/server/sse.js";
 import express from "express";
 import { findActualExecutable } from "spawn-rx";
-import { isSseError } from "./errors.js";
 import mcpProxy from "./mcpProxy.js";
 
 const SSE_HEADERS_PASSTHROUGH = ['Authorization'];
@@ -103,7 +102,7 @@ app.get("/sse", async (req, res) => {
     try {
       backingServerTransport = await createTransport(req);
     } catch (error) {
-      if (isSseError(error) && error.code === 401) {
+      if (error instanceof SseError && error.code === 401) {
         console.error("Received 401 Unauthorized from MCP server:", error.message);
         res.status(401).json(error);
         return;