fix: Extract function to utils

client/src/lib/hooks/useConnection.ts

@@ -30,7 +30,6 @@ import {
   Progress,
   LoggingLevel,
   ElicitRequestSchema,
-  isJSONRPCRequest,
 } from "@modelcontextprotocol/sdk/types.js";
 import { RequestOptions } from "@modelcontextprotocol/sdk/shared/protocol.js";
 import { useEffect, useState } from "react";
@@ -58,8 +57,7 @@ import { getMCPServerRequestTimeout } from "@/utils/configUtils";
 import { InspectorConfig } from "../configurationTypes";
 import { Transport } from "@modelcontextprotocol/sdk/shared/transport.js";
 import { CustomHeaders } from "../types/customHeaders";
-import { JsonSchemaType } from "@/utils/jsonUtils";
+import { resolveRefsInMessage } from "@/utils/schemaUtils";
-import { resolveRef } from "@/utils/schemaUtils";
 
 interface UseConnectionOptions {
   transportType: "stdio" | "sse" | "streamable-http";
@@ -687,29 +685,8 @@ export function useConnection({
         const protocolOnMessage = transport.onmessage;
         if (protocolOnMessage) {
           transport.onmessage = (message) => {
-            // Resolve $ref references in requests before validation
+            const resolvedMessage = resolveRefsInMessage(message);
-            if (isJSONRPCRequest(message) && message.params?.requestedSchema) {
+            protocolOnMessage(resolvedMessage);
-              const requestedSchema = message.params
-                .requestedSchema as JsonSchemaType;
-              if (requestedSchema?.properties) {
-                const resolvedProperties = Object.fromEntries(
-                  Object.entries(requestedSchema.properties).map(
-                    ([key, propSchema]) => [
-                      key,
-                      resolveRef(propSchema, requestedSchema),
-                    ],
-                  ),
-                );
-                message.params = {
-                  ...message.params,
-                  requestedSchema: {
-                    ...requestedSchema,
-                    properties: resolvedProperties,
-                  },
-                };
-              }
-            }
-            protocolOnMessage(message);
           };
         }
 

client/src/utils/schemaUtils.ts

@@ -1,7 +1,8 @@
 import type { JsonValue, JsonSchemaType, JsonObject } from "./jsonUtils";
 import Ajv from "ajv";
 import type { ValidateFunction } from "ajv";
-import type { Tool } from "@modelcontextprotocol/sdk/types.js";
+import type { Tool, JSONRPCMessage } from "@modelcontextprotocol/sdk/types.js";
+import { isJSONRPCRequest } from "@modelcontextprotocol/sdk/types.js";
 
 const ajv = new Ajv();
 
@@ -299,3 +300,40 @@ export function formatFieldLabel(key: string): string {
     .replace(/_/g, " ") // Replace underscores with spaces
     .replace(/^\w/, (c) => c.toUpperCase()); // Capitalize first letter
 }
+
+/**
+ * Resolves $ref references in a JSON-RPC message's requestedSchema
+ * @param message The JSON-RPC message that may contain $ref references
+ * @returns A new message with resolved $ref references, or the original message if no resolution is needed
+ */
+export function resolveRefsInMessage(message: JSONRPCMessage): JSONRPCMessage {
+  if (!isJSONRPCRequest(message) || !message.params?.requestedSchema) {
+    return message;
+  }
+
+  const requestedSchema = message.params.requestedSchema as JsonSchemaType;
+
+  if (!requestedSchema?.properties) {
+    return message;
+  }
+
+  const resolvedMessage = {
+    ...message,
+    params: {
+      ...message.params,
+      requestedSchema: {
+        ...requestedSchema,
+        properties: Object.fromEntries(
+          Object.entries(requestedSchema.properties).map(
+            ([key, propSchema]) => [
+              key,
+              resolveRef(propSchema, requestedSchema),
+            ],
+          ),
+        ),
+      },
+    },
+  };
+
+  return resolvedMessage;
+}