Merge pull request modelcontextprotocol#105 from devin-open-source/devin/1733551277-capability-negotiation

feat: implement capability negotiation for UI tabs

Author: ashwin-ant

client/src/App.tsx

@@ -19,10 +19,11 @@ import {
   Request,
   Resource,
   ResourceTemplate,
-  Result,
   Root,
   ServerNotification,
   Tool,
+  ServerCapabilitiesSchema,
+  Result,
 } from "@modelcontextprotocol/sdk/types.js";
 import { useCallback, useEffect, useRef, useState } from "react";
 
@@ -43,7 +44,7 @@ import {
 } from "lucide-react";
 
 import { toast } from "react-toastify";
-import { ZodType } from "zod";
+import { z, type ZodType } from "zod";
 import "./App.css";
 import ConsoleTab from "./components/ConsoleTab";
 import HistoryAndNotifications from "./components/History";
@@ -55,6 +56,8 @@ import SamplingTab, { PendingRequest } from "./components/SamplingTab";
 import Sidebar from "./components/Sidebar";
 import ToolsTab from "./components/ToolsTab";
 
+type ServerCapabilities = z.infer<typeof ServerCapabilitiesSchema>;
+
 const DEFAULT_REQUEST_TIMEOUT_MSEC = 10000;
 
 const params = new URLSearchParams(window.location.search);
@@ -67,6 +70,7 @@ const App = () => {
   const [connectionStatus, setConnectionStatus] = useState<
     "disconnected" | "connected" | "error"
   >("disconnected");
+  const [serverCapabilities, setServerCapabilities] = useState<ServerCapabilities | null>(null);
   const [resources, setResources] = useState<Resource[]>([]);
   const [resourceTemplates, setResourceTemplates] = useState<
     ResourceTemplate[]
@@ -455,6 +459,9 @@ const App = () => {
 
       await client.connect(clientTransport);
 
+      const capabilities = client.getServerCapabilities();
+      setServerCapabilities(capabilities ?? null);
+
       client.setRequestHandler(CreateMessageRequestSchema, (request) => {
         return new Promise<CreateMessageResult>((resolve, reject) => {
           setPendingSampleRequests((prev) => [
@@ -497,20 +504,27 @@ const App = () => {
         <div className="flex-1 overflow-auto">
           {mcpClient ? (
             <Tabs
-              defaultValue={window.location.hash.slice(1) || "resources"}
+              defaultValue={
+                Object.keys(serverCapabilities ?? {}).includes(window.location.hash.slice(1)) ?
+                window.location.hash.slice(1) :
+                serverCapabilities?.resources ? "resources" :
+                serverCapabilities?.prompts ? "prompts" :
+                serverCapabilities?.tools ? "tools" :
+                "ping"
+              }
               className="w-full p-4"
               onValueChange={(value) => (window.location.hash = value)}
             >
               <TabsList className="mb-4 p-0">
-                <TabsTrigger value="resources">
+                <TabsTrigger value="resources" disabled={!serverCapabilities?.resources}>
                   <Files className="w-4 h-4 mr-2" />
                   Resources
                 </TabsTrigger>
-                <TabsTrigger value="prompts">
+                <TabsTrigger value="prompts" disabled={!serverCapabilities?.prompts}>
                   <MessageSquare className="w-4 h-4 mr-2" />
                   Prompts
                 </TabsTrigger>
-                <TabsTrigger value="tools">
+                <TabsTrigger value="tools" disabled={!serverCapabilities?.tools}>
                   <Hammer className="w-4 h-4 mr-2" />
                   Tools
                 </TabsTrigger>
@@ -534,107 +548,117 @@ const App = () => {
               </TabsList>
 
               <div className="w-full">
-                <ResourcesTab
-                  resources={resources}
-                  resourceTemplates={resourceTemplates}
-                  listResources={() => {
-                    clearError("resources");
-                    listResources();
-                  }}
-                  clearResources={() => {
-                    setResources([]);
-                    setNextResourceCursor(undefined);
-                  }}
-                  listResourceTemplates={() => {
-                    clearError("resources");
-                    listResourceTemplates();
-                  }}
-                  clearResourceTemplates={() => {
-                    setResourceTemplates([]);
-                    setNextResourceTemplateCursor(undefined);
-                  }}
-                  readResource={(uri) => {
-                    clearError("resources");
-                    readResource(uri);
-                  }}
-                  selectedResource={selectedResource}
-                  setSelectedResource={(resource) => {
-                    clearError("resources");
-                    setSelectedResource(resource);
-                  }}
-                  resourceContent={resourceContent}
-                  nextCursor={nextResourceCursor}
-                  nextTemplateCursor={nextResourceTemplateCursor}
-                  error={errors.resources}
-                />
-                <PromptsTab
-                  prompts={prompts}
-                  listPrompts={() => {
-                    clearError("prompts");
-                    listPrompts();
-                  }}
-                  clearPrompts={() => {
-                    setPrompts([]);
-                    setNextPromptCursor(undefined);
-                  }}
-                  getPrompt={(name, args) => {
-                    clearError("prompts");
-                    getPrompt(name, args);
-                  }}
-                  selectedPrompt={selectedPrompt}
-                  setSelectedPrompt={(prompt) => {
-                    clearError("prompts");
-                    setSelectedPrompt(prompt);
-                  }}
-                  promptContent={promptContent}
-                  nextCursor={nextPromptCursor}
-                  error={errors.prompts}
-                />
-                <ToolsTab
-                  tools={tools}
-                  listTools={() => {
-                    clearError("tools");
-                    listTools();
-                  }}
-                  clearTools={() => {
-                    setTools([]);
-                    setNextToolCursor(undefined);
-                  }}
-                  callTool={(name, params) => {
-                    clearError("tools");
-                    callTool(name, params);
-                  }}
-                  selectedTool={selectedTool}
-                  setSelectedTool={(tool) => {
-                    clearError("tools");
-                    setSelectedTool(tool);
-                    setToolResult(null);
-                  }}
-                  toolResult={toolResult}
-                  nextCursor={nextToolCursor}
-                  error={errors.tools}
-                />
-                <ConsoleTab />
-                <PingTab
-                  onPingClick={() => {
-                    void makeRequest(
-                      {
-                        method: "ping" as const,
-                      },
-                      EmptyResultSchema,
-                    );
-                  }}
-                />
-                <SamplingTab
-                  pendingRequests={pendingSampleRequests}
-                  onApprove={handleApproveSampling}
-                  onReject={handleRejectSampling}
-                />
-                <RootsTab
-                  roots={roots}
-                  setRoots={setRoots}
-                  onRootsChange={handleRootsChange}
-                />
+                {!serverCapabilities?.resources && !serverCapabilities?.prompts && !serverCapabilities?.tools ? (
+                  <div className="flex items-center justify-center p-4">
+                    <p className="text-lg text-gray-500">
+                      The connected server does not support any MCP capabilities
+                    </p>
+                  </div>
+                ) : (
+                  <>
+                    <ResourcesTab
+                      resources={resources}
+                      resourceTemplates={resourceTemplates}
+                      listResources={() => {
+                        clearError("resources");
+                        listResources();
+                      }}
+                      clearResources={() => {
+                        setResources([]);
+                        setNextResourceCursor(undefined);
+                      }}
+                      listResourceTemplates={() => {
+                        clearError("resources");
+                        listResourceTemplates();
+                      }}
+                      clearResourceTemplates={() => {
+                        setResourceTemplates([]);
+                        setNextResourceTemplateCursor(undefined);
+                      }}
+                      readResource={(uri) => {
+                        clearError("resources");
+                        readResource(uri);
+                      }}
+                      selectedResource={selectedResource}
+                      setSelectedResource={(resource) => {
+                        clearError("resources");
+                        setSelectedResource(resource);
+                      }}
+                      resourceContent={resourceContent}
+                      nextCursor={nextResourceCursor}
+                      nextTemplateCursor={nextResourceTemplateCursor}
+                      error={errors.resources}
+                    />
+                    <PromptsTab
+                      prompts={prompts}
+                      listPrompts={() => {
+                        clearError("prompts");
+                        listPrompts();
+                      }}
+                      clearPrompts={() => {
+                        setPrompts([]);
+                        setNextPromptCursor(undefined);
+                      }}
+                      getPrompt={(name, args) => {
+                        clearError("prompts");
+                        getPrompt(name, args);
+                      }}
+                      selectedPrompt={selectedPrompt}
+                      setSelectedPrompt={(prompt) => {
+                        clearError("prompts");
+                        setSelectedPrompt(prompt);
+                      }}
+                      promptContent={promptContent}
+                      nextCursor={nextPromptCursor}
+                      error={errors.prompts}
+                    />
+                    <ToolsTab
+                      tools={tools}
+                      listTools={() => {
+                        clearError("tools");
+                        listTools();
+                      }}
+                      clearTools={() => {
+                        setTools([]);
+                        setNextToolCursor(undefined);
+                      }}
+                      callTool={(name, params) => {
+                        clearError("tools");
+                        callTool(name, params);
+                      }}
+                      selectedTool={selectedTool}
+                      setSelectedTool={(tool) => {
+                        clearError("tools");
+                        setSelectedTool(tool);
+                        setToolResult(null);
+                      }}
+                      toolResult={toolResult}
+                      nextCursor={nextToolCursor}
+                      error={errors.tools}
+                    />
+                    <ConsoleTab />
+                    <PingTab
+                      onPingClick={() => {
+                        void makeRequest(
+                          {
+                            method: "ping" as const,
+                          },
+                          EmptyResultSchema,
+                        );
+                      }}
+                    />
+                    <SamplingTab
+                      pendingRequests={pendingSampleRequests}
+                      onApprove={handleApproveSampling}
+                      onReject={handleRejectSampling}
+                    />
+                    <RootsTab
+                      roots={roots}
+                      setRoots={setRoots}
+                      onRootsChange={handleRootsChange}
+                    />
+                  </>
+                )}
               </div>
             </Tabs>
           ) : (