diff --git a/README.md b/README.md
index 31c7535..ca29ca2 100644
--- a/README.md
+++ b/README.md
@@ -40,7 +40,7 @@ For more details on ways to use the inspector, see the [Inspector section of the
 
 ### Authentication
 
-The inspector supports bearer token authentication for SSE connections. Enter your token in the UI when connecting to an MCP server, and it will be sent in the Authorization header.
+The inspector supports bearer token authentication for SSE connections. Enter your token in the UI when connecting to an MCP server, and it will be sent in the Authorization header. You can override the header name using the input field in the sidebar.
 
 ### Security Considerations
 
diff --git a/client/package.json b/client/package.json
index 0734ea9..3b50ab1 100644
--- a/client/package.json
+++ b/client/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@modelcontextprotocol/inspector-client",
-  "version": "0.8.2",
+  "version": "0.9.0",
   "description": "Client-side application for the Model Context Protocol inspector",
   "license": "MIT",
   "author": "Anthropic, PBC (https://anthropic.com)",
diff --git a/client/src/App.tsx b/client/src/App.tsx
index 4f99ffd..5964bd8 100644
--- a/client/src/App.tsx
+++ b/client/src/App.tsx
@@ -117,6 +117,10 @@ const App = () => {
     return localStorage.getItem("lastBearerToken") || "";
   });
 
+  const [headerName, setHeaderName] = useState<string>(() => {
+    return localStorage.getItem("lastHeaderName") || "";
+  });
+
   const [pendingSampleRequests, setPendingSampleRequests] = useState<
     Array<
       PendingRequest & {
@@ -169,6 +173,7 @@ const App = () => {
     sseUrl,
     env,
     bearerToken,
+    headerName,
     config,
     onNotification: (notification) => {
       setNotifications((prev) => [...prev, notification as ServerNotification]);
@@ -208,6 +213,10 @@ const App = () => {
     localStorage.setItem("lastBearerToken", bearerToken);
   }, [bearerToken]);
 
+  useEffect(() => {
+    localStorage.setItem("lastHeaderName", headerName);
+  }, [headerName]);
+
   useEffect(() => {
     localStorage.setItem(CONFIG_LOCAL_STORAGE_KEY, JSON.stringify(config));
   }, [config]);
@@ -467,6 +476,10 @@ const App = () => {
     setLogLevel(level);
   };
 
+  const clearStdErrNotifications = () => {
+    setStdErrNotifications([]);
+  };
+
   if (window.location.pathname === "/oauth/callback") {
     const OAuthCallback = React.lazy(
       () => import("./components/OAuthCallback"),
@@ -496,12 +509,15 @@ const App = () => {
         setConfig={setConfig}
         bearerToken={bearerToken}
         setBearerToken={setBearerToken}
+        headerName={headerName}
+        setHeaderName={setHeaderName}
         onConnect={connectMcpServer}
         onDisconnect={disconnectMcpServer}
         stdErrNotifications={stdErrNotifications}
         logLevel={logLevel}
         sendLogLevelRequest={sendLogLevelRequest}
         loggingSupported={!!serverCapabilities?.logging || false}
+        clearStdErrNotifications={clearStdErrNotifications}
       />
       <div className="flex-1 flex flex-col overflow-hidden">
         <div className="flex-1 overflow-auto">
diff --git a/client/src/components/JsonView.tsx b/client/src/components/JsonView.tsx
index 3fcbf8e..bd7ef64 100644
--- a/client/src/components/JsonView.tsx
+++ b/client/src/components/JsonView.tsx
@@ -227,7 +227,7 @@ const JsonNode = memo(
             )}
             <pre
               className={clsx(
-                typeStyleMap.string,
+                isError ? typeStyleMap.error : typeStyleMap.string,
                 "break-all whitespace-pre-wrap",
               )}
             >
diff --git a/client/src/components/Sidebar.tsx b/client/src/components/Sidebar.tsx
index 2ddb18d..c736558 100644
--- a/client/src/components/Sidebar.tsx
+++ b/client/src/components/Sidebar.tsx
@@ -51,9 +51,12 @@ interface SidebarProps {
   setEnv: (env: Record<string, string>) => void;
   bearerToken: string;
   setBearerToken: (token: string) => void;
+  headerName?: string;
+  setHeaderName?: (name: string) => void;
   onConnect: () => void;
   onDisconnect: () => void;
   stdErrNotifications: StdErrNotification[];
+  clearStdErrNotifications: () => void;
   logLevel: LoggingLevel;
   sendLogLevelRequest: (level: LoggingLevel) => void;
   loggingSupported: boolean;
@@ -75,9 +78,12 @@ const Sidebar = ({
   setEnv,
   bearerToken,
   setBearerToken,
+  headerName,
+  setHeaderName,
   onConnect,
   onDisconnect,
   stdErrNotifications,
+  clearStdErrNotifications,
   logLevel,
   sendLogLevelRequest,
   loggingSupported,
@@ -174,6 +180,7 @@ const Sidebar = ({
                   variant="outline"
                   onClick={() => setShowBearerToken(!showBearerToken)}
                   className="flex items-center w-full"
+                  data-testid="auth-button"
                   aria-expanded={showBearerToken}
                 >
                   {showBearerToken ? (
@@ -185,6 +192,16 @@ const Sidebar = ({
                 </Button>
                 {showBearerToken && (
                   <div className="space-y-2">
+                    <label className="text-sm font-medium">Header Name</label>
+                    <Input
+                      placeholder="Authorization"
+                      onChange={(e) =>
+                        setHeaderName && setHeaderName(e.target.value)
+                      }
+                      data-testid="header-input"
+                      className="font-mono"
+                      value={headerName}
+                    />
                     <label
                       className="text-sm font-medium"
                       htmlFor="bearer-token-input"
@@ -196,6 +213,7 @@ const Sidebar = ({
                       placeholder="Bearer Token"
                       value={bearerToken}
                       onChange={(e) => setBearerToken(e.target.value)}
+                      data-testid="bearer-token-input"
                       className="font-mono"
                       type="password"
                     />
@@ -514,9 +532,19 @@ const Sidebar = ({
             {stdErrNotifications.length > 0 && (
               <>
                 <div className="mt-4 border-t border-gray-200 pt-4">
-                  <h3 className="text-sm font-medium">
-                    Error output from MCP server
-                  </h3>
+                  <div className="flex justify-between items-center">
+                    <h3 className="text-sm font-medium">
+                      Error output from MCP server
+                    </h3>
+                    <Button
+                      variant="outline"
+                      size="sm"
+                      onClick={clearStdErrNotifications}
+                      className="h-8 px-2"
+                    >
+                      Clear
+                    </Button>
+                  </div>
                   <div className="mt-2 max-h-80 overflow-y-auto">
                     {stdErrNotifications.map((notification, index) => (
                       <div
diff --git a/client/src/components/__tests__/Sidebar.test.tsx b/client/src/components/__tests__/Sidebar.test.tsx
index 8e72b00..980dc01 100644
--- a/client/src/components/__tests__/Sidebar.test.tsx
+++ b/client/src/components/__tests__/Sidebar.test.tsx
@@ -1,4 +1,5 @@
 import { render, screen, fireEvent } from "@testing-library/react";
+import "@testing-library/jest-dom";
 import { describe, it, beforeEach, jest } from "@jest/globals";
 import Sidebar from "../Sidebar";
 import { DEFAULT_INSPECTOR_CONFIG } from "@/lib/constants";
@@ -29,6 +30,7 @@ describe("Sidebar Environment Variables", () => {
     onConnect: jest.fn(),
     onDisconnect: jest.fn(),
     stdErrNotifications: [],
+    clearStdErrNotifications: jest.fn(),
     logLevel: "info" as const,
     sendLogLevelRequest: jest.fn(),
     loggingSupported: true,
@@ -108,6 +110,157 @@ describe("Sidebar Environment Variables", () => {
     });
   });
 
+  describe("Authentication", () => {
+    const openAuthSection = () => {
+      const button = screen.getByTestId("auth-button");
+      fireEvent.click(button);
+    };
+
+    it("should update bearer token", () => {
+      const setBearerToken = jest.fn();
+      renderSidebar({
+        bearerToken: "",
+        setBearerToken,
+        transportType: "sse", // Set transport type to SSE
+      });
+
+      openAuthSection();
+
+      const tokenInput = screen.getByTestId("bearer-token-input");
+      fireEvent.change(tokenInput, { target: { value: "new_token" } });
+
+      expect(setBearerToken).toHaveBeenCalledWith("new_token");
+    });
+
+    it("should update header name", () => {
+      const setHeaderName = jest.fn();
+      renderSidebar({
+        headerName: "Authorization",
+        setHeaderName,
+        transportType: "sse",
+      });
+
+      openAuthSection();
+
+      const headerInput = screen.getByTestId("header-input");
+      fireEvent.change(headerInput, { target: { value: "X-Custom-Auth" } });
+
+      expect(setHeaderName).toHaveBeenCalledWith("X-Custom-Auth");
+    });
+
+    it("should clear bearer token", () => {
+      const setBearerToken = jest.fn();
+      renderSidebar({
+        bearerToken: "existing_token",
+        setBearerToken,
+        transportType: "sse", // Set transport type to SSE
+      });
+
+      openAuthSection();
+
+      const tokenInput = screen.getByTestId("bearer-token-input");
+      fireEvent.change(tokenInput, { target: { value: "" } });
+
+      expect(setBearerToken).toHaveBeenCalledWith("");
+    });
+
+    it("should properly render bearer token input", () => {
+      const { rerender } = renderSidebar({
+        bearerToken: "existing_token",
+        transportType: "sse", // Set transport type to SSE
+      });
+
+      openAuthSection();
+
+      // Token input should be a password field
+      const tokenInput = screen.getByTestId("bearer-token-input");
+      expect(tokenInput).toHaveProperty("type", "password");
+
+      // Update the token
+      fireEvent.change(tokenInput, { target: { value: "new_token" } });
+
+      // Rerender with updated token
+      rerender(
+        <TooltipProvider>
+          <Sidebar
+            {...defaultProps}
+            bearerToken="new_token"
+            transportType="sse"
+          />
+        </TooltipProvider>,
+      );
+
+      // Token input should still exist after update
+      expect(screen.getByTestId("bearer-token-input")).toBeInTheDocument();
+    });
+
+    it("should maintain token visibility state after update", () => {
+      const { rerender } = renderSidebar({
+        bearerToken: "existing_token",
+        transportType: "sse", // Set transport type to SSE
+      });
+
+      openAuthSection();
+
+      // Token input should be a password field
+      const tokenInput = screen.getByTestId("bearer-token-input");
+      expect(tokenInput).toHaveProperty("type", "password");
+
+      // Update the token
+      fireEvent.change(tokenInput, { target: { value: "new_token" } });
+
+      // Rerender with updated token
+      rerender(
+        <TooltipProvider>
+          <Sidebar
+            {...defaultProps}
+            bearerToken="new_token"
+            transportType="sse"
+          />
+        </TooltipProvider>,
+      );
+
+      // Token input should still exist after update
+      expect(screen.getByTestId("bearer-token-input")).toBeInTheDocument();
+    });
+
+    it("should maintain header name when toggling auth section", () => {
+      renderSidebar({
+        headerName: "X-API-Key",
+        transportType: "sse",
+      });
+
+      // Open auth section
+      openAuthSection();
+
+      // Verify header name is displayed
+      const headerInput = screen.getByTestId("header-input");
+      expect(headerInput).toHaveValue("X-API-Key");
+
+      // Close auth section
+      const authButton = screen.getByTestId("auth-button");
+      fireEvent.click(authButton);
+
+      // Reopen auth section
+      fireEvent.click(authButton);
+
+      // Verify header name is still preserved
+      expect(screen.getByTestId("header-input")).toHaveValue("X-API-Key");
+    });
+
+    it("should display default header name when not specified", () => {
+      renderSidebar({
+        headerName: undefined,
+        transportType: "sse",
+      });
+
+      openAuthSection();
+
+      const headerInput = screen.getByTestId("header-input");
+      expect(headerInput).toHaveAttribute("placeholder", "Authorization");
+    });
+  });
+
   describe("Key Editing", () => {
     it("should maintain order when editing first key", () => {
       const setEnv = jest.fn();
diff --git a/client/src/lib/hooks/useConnection.ts b/client/src/lib/hooks/useConnection.ts
index ac4605c..d5d7070 100644
--- a/client/src/lib/hooks/useConnection.ts
+++ b/client/src/lib/hooks/useConnection.ts
@@ -48,6 +48,7 @@ interface UseConnectionOptions {
   sseUrl: string;
   env: Record<string, string>;
   bearerToken?: string;
+  headerName?: string;
   config: InspectorConfig;
   onNotification?: (notification: Notification) => void;
   onStdErrNotification?: (notification: Notification) => void;
@@ -64,6 +65,7 @@ export function useConnection({
   sseUrl,
   env,
   bearerToken,
+  headerName,
   config,
   onNotification,
   onStdErrNotification,
@@ -293,7 +295,8 @@ export function useConnection({
       // Use manually provided bearer token if available, otherwise use OAuth tokens
       const token = bearerToken || (await authProvider.tokens())?.access_token;
       if (token) {
-        headers["Authorization"] = `Bearer ${token}`;
+        const authHeaderName = headerName || "Authorization";
+        headers[authHeaderName] = `Bearer ${token}`;
       }
 
       const clientTransport = new SSEClientTransport(mcpProxyServerUrl, {
diff --git a/package-lock.json b/package-lock.json
index dcc03d4..89e5240 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,20 +1,20 @@
 {
   "name": "@modelcontextprotocol/inspector",
-  "version": "0.8.2",
+  "version": "0.9.0",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "@modelcontextprotocol/inspector",
-      "version": "0.8.2",
+      "version": "0.9.0",
       "license": "MIT",
       "workspaces": [
         "client",
         "server"
       ],
       "dependencies": {
-        "@modelcontextprotocol/inspector-client": "^0.8.2",
-        "@modelcontextprotocol/inspector-server": "^0.8.2",
+        "@modelcontextprotocol/inspector-client": "^0.9.0",
+        "@modelcontextprotocol/inspector-server": "^0.9.0",
         "concurrently": "^9.0.1",
         "shell-quote": "^1.8.2",
         "spawn-rx": "^5.1.2",
@@ -32,7 +32,7 @@
     },
     "client": {
       "name": "@modelcontextprotocol/inspector-client",
-      "version": "0.8.2",
+      "version": "0.9.0",
       "license": "MIT",
       "dependencies": {
         "@modelcontextprotocol/sdk": "^1.9.0",
@@ -9500,7 +9500,7 @@
     },
     "server": {
       "name": "@modelcontextprotocol/inspector-server",
-      "version": "0.8.2",
+      "version": "0.9.0",
       "license": "MIT",
       "dependencies": {
         "@modelcontextprotocol/sdk": "^1.9.0",
diff --git a/package.json b/package.json
index f9d2217..a3e10c1 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@modelcontextprotocol/inspector",
-  "version": "0.8.2",
+  "version": "0.9.0",
   "description": "Model Context Protocol inspector",
   "license": "MIT",
   "author": "Anthropic, PBC (https://anthropic.com)",
@@ -36,8 +36,8 @@
     "publish-all": "npm publish --workspaces --access public && npm publish --access public"
   },
   "dependencies": {
-    "@modelcontextprotocol/inspector-client": "^0.8.2",
-    "@modelcontextprotocol/inspector-server": "^0.8.2",
+    "@modelcontextprotocol/inspector-client": "^0.9.0",
+    "@modelcontextprotocol/inspector-server": "^0.9.0",
     "concurrently": "^9.0.1",
     "shell-quote": "^1.8.2",
     "spawn-rx": "^5.1.2",
diff --git a/server/package.json b/server/package.json
index 248db61..4927ce0 100644
--- a/server/package.json
+++ b/server/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@modelcontextprotocol/inspector-server",
-  "version": "0.8.2",
+  "version": "0.9.0",
   "description": "Server-side application for the Model Context Protocol inspector",
   "license": "MIT",
   "author": "Anthropic, PBC (https://anthropic.com)",