Merge branch 'main' into feat/proxyServerUrl

.github/workflows/main.yml

@@ -25,6 +25,11 @@ jobs:
       # Working around https://github.com/npm/cli/issues/4828
       # - run: npm ci
       - run: npm install --no-package-lock
+
+      - name: Run client tests
+        working-directory: ./client
+        run: npm test
+
       - run: npm run build
 
   publish:

.gitignore

@@ -4,3 +4,4 @@ server/build
 client/dist
 client/tsconfig.app.tsbuildinfo
 client/tsconfig.node.tsbuildinfo
+.vscode

bin/cli.js

@@ -27,9 +27,15 @@ async function main() {
     }
 
     if (parsingFlags && arg === "-e" && i + 1 < args.length) {
-      const [key, value] = args[++i].split("=");
-      if (key && value) {
+      const envVar = args[++i];
+      const equalsIndex = envVar.indexOf("=");
+
+      if (equalsIndex !== -1) {
+        const key = envVar.substring(0, equalsIndex);
+        const value = envVar.substring(equalsIndex + 1);
         envVars[key] = value;
+      } else {
+        envVars[envVar] = "";
       }
     } else if (!command) {
       command = arg;

client/jest.config.cjs

@@ -0,0 +1,37 @@
+module.exports = {
+  preset: "ts-jest",
+  testEnvironment: "jsdom",
+  moduleNameMapper: {
+    "^@/(.*)$": "<rootDir>/src/$1",
+    "^../components/DynamicJsonForm$":
+      "<rootDir>/src/utils/__mocks__/DynamicJsonForm.ts",
+    "^../../components/DynamicJsonForm$":
+      "<rootDir>/src/utils/__mocks__/DynamicJsonForm.ts",
+  },
+  transform: {
+    "^.+\\.tsx?$": [
+      "ts-jest",
+      {
+        useESM: true,
+        jsx: "react-jsx",
+        tsconfig: "tsconfig.jest.json",
+      },
+    ],
+  },
+  extensionsToTreatAsEsm: [".ts", ".tsx"],
+  testRegex: "(/__tests__/.*|(\\.|/)(test|spec))\\.(jsx?|tsx?)$",
+  // Exclude directories and files that don't need to be tested
+  testPathIgnorePatterns: [
+    "/node_modules/",
+    "/dist/",
+    "/bin/",
+    "\\.config\\.(js|ts|cjs|mjs)$",
+  ],
+  // Exclude the same patterns from coverage reports
+  coveragePathIgnorePatterns: [
+    "/node_modules/",
+    "/dist/",
+    "/bin/",
+    "\\.config\\.(js|ts|cjs|mjs)$",
+  ],
+};

client/package.json

@@ -18,7 +18,9 @@
     "dev": "vite",
     "build": "tsc -b && vite build",
     "lint": "eslint .",
-    "preview": "vite preview"
+    "preview": "vite preview",
+    "test": "jest --config jest.config.cjs",
+    "test:watch": "jest --config jest.config.cjs --watch"
   },
   "dependencies": {
     "@modelcontextprotocol/sdk": "^1.6.1",
@@ -35,8 +37,8 @@
     "clsx": "^2.1.1",
     "cmdk": "^1.0.4",
     "lucide-react": "^0.447.0",
-    "prismjs": "^1.29.0",
     "pkce-challenge": "^4.1.0",
+    "prismjs": "^1.29.0",
     "react": "^18.3.1",
     "react-dom": "^18.3.1",
     "react-simple-code-editor": "^0.14.1",
@@ -48,18 +50,23 @@
   },
   "devDependencies": {
     "@eslint/js": "^9.11.1",
+    "@types/jest": "^29.5.14",
     "@types/node": "^22.7.5",
     "@types/react": "^18.3.10",
     "@types/react-dom": "^18.3.0",
     "@types/serve-handler": "^6.1.4",
     "@vitejs/plugin-react": "^4.3.2",
     "autoprefixer": "^10.4.20",
+    "co": "^4.6.0",
     "eslint": "^9.11.1",
     "eslint-plugin-react-hooks": "^5.1.0-rc.0",
     "eslint-plugin-react-refresh": "^0.4.12",
     "globals": "^15.9.0",
+    "jest": "^29.7.0",
+    "jest-environment-jsdom": "^29.7.0",
     "postcss": "^8.4.47",
     "tailwindcss": "^3.4.13",
+    "ts-jest": "^29.2.6",
     "typescript": "^5.5.3",
     "typescript-eslint": "^8.7.0",
     "vite": "^5.4.8"

client/src/App.tsx

@@ -15,6 +15,7 @@ import {
   Root,
   ServerNotification,
   Tool,
+  LoggingLevel,
 } from "@modelcontextprotocol/sdk/types.js";
 import React, { Suspense, useEffect, useRef, useState } from "react";
 import { useConnection } from "./lib/hooks/useConnection";
@@ -91,6 +92,7 @@ const App = () => {
       (localStorage.getItem("lastTransportType") as "stdio" | "sse") || "stdio"
     );
   });
+  const [logLevel, setLogLevel] = useState<LoggingLevel>("debug");
   const [notifications, setNotifications] = useState<ServerNotification[]>([]);
   const [stdErrNotifications, setStdErrNotifications] = useState<
     StdErrNotification[]
@@ -412,6 +414,17 @@ const App = () => {
     await sendNotification({ method: "notifications/roots/list_changed" });
   };
 
+  const sendLogLevelRequest = async (level: LoggingLevel) => {
+    await makeRequest(
+      {
+        method: "logging/setLevel" as const,
+        params: { level },
+      },
+      z.object({}),
+    );
+    setLogLevel(level);
+  };
+
   return (
     <div className="flex h-screen bg-background">
       <Sidebar
@@ -430,6 +443,9 @@ const App = () => {
         setBearerToken={setBearerToken}
         onConnect={connectMcpServer}
         stdErrNotifications={stdErrNotifications}
+        logLevel={logLevel}
+        sendLogLevelRequest={sendLogLevelRequest}
+        loggingSupported={!!serverCapabilities?.logging || false}
       />
       <div className="flex-1 flex flex-col overflow-hidden">
         <div className="flex-1 overflow-auto">

client/src/components/DynamicJsonForm.tsx

@@ -1,26 +1,36 @@
-import { useState } from "react";
+import { useState, useEffect, useCallback, useRef } from "react";
 import { Button } from "@/components/ui/button";
 import { Input } from "@/components/ui/input";
 import { Label } from "@/components/ui/label";
 import JsonEditor from "./JsonEditor";
+import { updateValueAtPath, JsonObject } from "@/utils/jsonPathUtils";
+import { generateDefaultValue, formatFieldLabel } from "@/utils/schemaUtils";
 
 export type JsonValue =
   | string
   | number
   | boolean
   | null
+  | undefined
   | JsonValue[]
   | { [key: string]: JsonValue };
 
 export type JsonSchemaType = {
-  type: "string" | "number" | "integer" | "boolean" | "array" | "object";
+  type:
+    | "string"
+    | "number"
+    | "integer"
+    | "boolean"
+    | "array"
+    | "object"
+    | "null";
   description?: string;
+  required?: boolean;
+  default?: JsonValue;
   properties?: Record<string, JsonSchemaType>;
   items?: JsonSchemaType;
 };
 
-type JsonObject = { [key: string]: JsonValue };
-
 interface DynamicJsonFormProps {
   schema: JsonSchemaType;
   value: JsonValue;
@@ -28,13 +38,6 @@ interface DynamicJsonFormProps {
   maxDepth?: number;
 }
 
-const formatFieldLabel = (key: string): string => {
-  return key
-    .replace(/([A-Z])/g, " $1") // Insert space before capital letters
-    .replace(/_/g, " ") // Replace underscores with spaces
-    .replace(/^\w/, (c) => c.toUpperCase()); // Capitalize first letter
-};
-
 const DynamicJsonForm = ({
   schema,
   value,
@@ -43,29 +46,65 @@ const DynamicJsonForm = ({
 }: DynamicJsonFormProps) => {
   const [isJsonMode, setIsJsonMode] = useState(false);
   const [jsonError, setJsonError] = useState<string>();
+  // Store the raw JSON string to allow immediate feedback during typing
+  // while deferring parsing until the user stops typing
+  const [rawJsonValue, setRawJsonValue] = useState<string>(
+    JSON.stringify(value ?? generateDefaultValue(schema), null, 2),
+  );
 
-  const generateDefaultValue = (propSchema: JsonSchemaType): JsonValue => {
-    switch (propSchema.type) {
-      case "string":
-        return "";
-      case "number":
-      case "integer":
-        return 0;
-      case "boolean":
-        return false;
-      case "array":
-        return [];
-      case "object": {
-        const obj: JsonObject = {};
-        if (propSchema.properties) {
-          Object.entries(propSchema.properties).forEach(([key, prop]) => {
-            obj[key] = generateDefaultValue(prop);
-          });
+  // Use a ref to manage debouncing timeouts to avoid parsing JSON
+  // on every keystroke which would be inefficient and error-prone
+  const timeoutRef = useRef<ReturnType<typeof setTimeout>>();
+
+  // Debounce JSON parsing and parent updates to handle typing gracefully
+  const debouncedUpdateParent = useCallback(
+    (jsonString: string) => {
+      // Clear any existing timeout
+      if (timeoutRef.current) {
+        clearTimeout(timeoutRef.current);
       }
-        return obj;
+
+      // Set a new timeout
+      timeoutRef.current = setTimeout(() => {
+        try {
+          const parsed = JSON.parse(jsonString);
+          onChange(parsed);
+          setJsonError(undefined);
+        } catch {
+          // Don't set error during normal typing
         }
-      default:
-        return null;
+      }, 300);
+    },
+    [onChange, setJsonError],
+  );
+
+  // Update rawJsonValue when value prop changes
+  useEffect(() => {
+    if (!isJsonMode) {
+      setRawJsonValue(
+        JSON.stringify(value ?? generateDefaultValue(schema), null, 2),
+      );
+    }
+  }, [value, schema, isJsonMode]);
+
+  const handleSwitchToFormMode = () => {
+    if (isJsonMode) {
+      // When switching to Form mode, ensure we have valid JSON
+      try {
+        const parsed = JSON.parse(rawJsonValue);
+        // Update the parent component's state with the parsed value
+        onChange(parsed);
+        // Switch to form mode
+        setIsJsonMode(false);
+      } catch (err) {
+        setJsonError(err instanceof Error ? err.message : "Invalid JSON");
+      }
+    } else {
+      // Update raw JSON value when switching to JSON mode
+      setRawJsonValue(
+        JSON.stringify(value ?? generateDefaultValue(schema), null, 2),
+      );
+      setIsJsonMode(true);
     }
   };
 
@@ -103,21 +142,68 @@ const DynamicJsonForm = ({
 
     switch (propSchema.type) {
       case "string":
+        return (
+          <Input
+            type="text"
+            value={(currentValue as string) ?? ""}
+            onChange={(e) => {
+              const val = e.target.value;
+              // Allow clearing non-required fields by setting undefined
+              // This preserves the distinction between empty string and unset
+              if (!val && !propSchema.required) {
+                handleFieldChange(path, undefined);
+              } else {
+                handleFieldChange(path, val);
+              }
+            }}
+            placeholder={propSchema.description}
+            required={propSchema.required}
+          />
+        );
       case "number":
+        return (
+          <Input
+            type="number"
+            value={(currentValue as number)?.toString() ?? ""}
+            onChange={(e) => {
+              const val = e.target.value;
+              // Allow clearing non-required number fields
+              // This preserves the distinction between 0 and unset
+              if (!val && !propSchema.required) {
+                handleFieldChange(path, undefined);
+              } else {
+                const num = Number(val);
+                if (!isNaN(num)) {
+                  handleFieldChange(path, num);
+                }
+              }
+            }}
+            placeholder={propSchema.description}
+            required={propSchema.required}
+          />
+        );
       case "integer":
         return (
           <Input
-            type={propSchema.type === "string" ? "text" : "number"}
-            value={(currentValue as string | number) ?? ""}
-            onChange={(e) =>
-              handleFieldChange(
-                path,
-                propSchema.type === "string"
-                  ? e.target.value
-                  : Number(e.target.value),
-              )
+            type="number"
+            step="1"
+            value={(currentValue as number)?.toString() ?? ""}
+            onChange={(e) => {
+              const val = e.target.value;
+              // Allow clearing non-required integer fields
+              // This preserves the distinction between 0 and unset
+              if (!val && !propSchema.required) {
+                handleFieldChange(path, undefined);
+              } else {
+                const num = Number(val);
+                // Only update if it's a valid integer
+                if (!isNaN(num) && Number.isInteger(num)) {
+                  handleFieldChange(path, num);
                 }
+              }
+            }}
             placeholder={propSchema.description}
+            required={propSchema.required}
           />
         );
       case "boolean":
@@ -127,10 +213,15 @@ const DynamicJsonForm = ({
             checked={(currentValue as boolean) ?? false}
             onChange={(e) => handleFieldChange(path, e.target.checked)}
             className="w-4 h-4"
+            required={propSchema.required}
           />
         );
-      case "object":
-        if (!propSchema.properties) return null;
+      case "object": {
+        // Handle case where we have a value but no schema properties
+        const objectValue = (currentValue as JsonObject) || {};
+
+        // If we have schema properties, use them to render fields
+        if (propSchema.properties) {
           return (
             <div className="space-y-4 border rounded-md p-4">
               {Object.entries(propSchema.properties).map(([key, prop]) => (
@@ -138,7 +229,7 @@ const DynamicJsonForm = ({
                   <Label>{formatFieldLabel(key)}</Label>
                   {renderFormFields(
                     prop,
-                  (currentValue as JsonObject)?.[key],
+                    objectValue[key],
                     [...path, key],
                     depth + 1,
                   )}
@@ -146,6 +237,29 @@ const DynamicJsonForm = ({
               ))}
             </div>
           );
+        }
+        // If we have a value but no schema properties, render fields based on the value
+        else if (Object.keys(objectValue).length > 0) {
+          return (
+            <div className="space-y-4 border rounded-md p-4">
+              {Object.entries(objectValue).map(([key, value]) => (
+                <div key={key} className="space-y-2">
+                  <Label>{formatFieldLabel(key)}</Label>
+                  <Input
+                    type="text"
+                    value={String(value)}
+                    onChange={(e) =>
+                      handleFieldChange([...path, key], e.target.value)
+                    }
+                  />
+                </div>
+              ))}
+            </div>
+          );
+        }
+        // If we have neither schema properties nor value, return null
+        return null;
+      }
       case "array": {
         const arrayValue = Array.isArray(currentValue) ? currentValue : [];
         if (!propSchema.items) return null;
@@ -187,9 +301,12 @@ const DynamicJsonForm = ({
                 variant="outline"
                 size="sm"
                 onClick={() => {
+                  const defaultValue = generateDefaultValue(
+                    propSchema.items as JsonSchemaType,
+                  );
                   handleFieldChange(path, [
                     ...arrayValue,
-                    generateDefaultValue(propSchema.items as JsonSchemaType),
+                    defaultValue ?? null,
                   ]);
                 }}
                 title={
@@ -215,139 +332,65 @@ const DynamicJsonForm = ({
       return;
     }
 
-    const updateArray = (
-      array: JsonValue[],
-      path: string[],
-      value: JsonValue,
-    ): JsonValue[] => {
-      const [index, ...restPath] = path;
-      const arrayIndex = Number(index);
-
-      // Validate array index
-      if (isNaN(arrayIndex)) {
-        console.error(`Invalid array index: ${index}`);
-        return array;
-      }
-
-      // Check array bounds
-      if (arrayIndex < 0) {
-        console.error(`Array index out of bounds: ${arrayIndex} < 0`);
-        return array;
-      }
-
-      const newArray = [...array];
-
-      if (restPath.length === 0) {
-        newArray[arrayIndex] = value;
-      } else {
-        // Ensure index position exists
-        if (arrayIndex >= array.length) {
-          console.warn(`Extending array to index ${arrayIndex}`);
-          newArray.length = arrayIndex + 1;
-          newArray.fill(null, array.length, arrayIndex);
-        }
-        newArray[arrayIndex] = updateValue(
-          newArray[arrayIndex],
-          restPath,
-          value,
-        );
-      }
-      return newArray;
-    };
-
-    const updateObject = (
-      obj: JsonObject,
-      path: string[],
-      value: JsonValue,
-    ): JsonObject => {
-      const [key, ...restPath] = path;
-
-      // Validate object key
-      if (typeof key !== "string") {
-        console.error(`Invalid object key: ${key}`);
-        return obj;
-      }
-
-      const newObj = { ...obj };
-
-      if (restPath.length === 0) {
-        newObj[key] = value;
-      } else {
-        // Ensure key exists
-        if (!(key in newObj)) {
-          console.warn(`Creating new key in object: ${key}`);
-          newObj[key] = {};
-        }
-        newObj[key] = updateValue(newObj[key], restPath, value);
-      }
-      return newObj;
-    };
-
-    const updateValue = (
-      current: JsonValue,
-      path: string[],
-      value: JsonValue,
-    ): JsonValue => {
-      if (path.length === 0) return value;
-
     try {
-        if (!current) {
-          current = !isNaN(Number(path[0])) ? [] : {};
-        }
-
-        // Type checking
-        if (Array.isArray(current)) {
-          return updateArray(current, path, value);
-        } else if (typeof current === "object" && current !== null) {
-          return updateObject(current, path, value);
-        } else {
-          console.error(
-            `Cannot update path ${path.join(".")} in non-object/array value:`,
-            current,
-          );
-          return current;
-        }
-      } catch (error) {
-        console.error(`Error updating value at path ${path.join(".")}:`, error);
-        return current;
-      }
-    };
-
-    try {
-      const newValue = updateValue(value, path, fieldValue);
+      const newValue = updateValueAtPath(value, path, fieldValue);
       onChange(newValue);
     } catch (error) {
       console.error("Failed to update form value:", error);
-      // Keep the original value unchanged
       onChange(value);
     }
   };
 
+  const shouldUseJsonMode =
+    schema.type === "object" &&
+    (!schema.properties || Object.keys(schema.properties).length === 0);
+
+  useEffect(() => {
+    if (shouldUseJsonMode && !isJsonMode) {
+      setIsJsonMode(true);
+    }
+  }, [shouldUseJsonMode, isJsonMode]);
+
   return (
     <div className="space-y-4">
       <div className="flex justify-end">
-        <Button
-          variant="outline"
-          size="sm"
-          onClick={() => setIsJsonMode(!isJsonMode)}
-        >
+        <Button variant="outline" size="sm" onClick={handleSwitchToFormMode}>
           {isJsonMode ? "Switch to Form" : "Switch to JSON"}
         </Button>
       </div>
 
       {isJsonMode ? (
         <JsonEditor
-          value={JSON.stringify(value ?? generateDefaultValue(schema), null, 2)}
+          value={rawJsonValue}
           onChange={(newValue) => {
-            try {
-              onChange(JSON.parse(newValue));
-              setJsonError(undefined);
-            } catch (err) {
-              setJsonError(err instanceof Error ? err.message : "Invalid JSON");
-            }
+            // Always update local state
+            setRawJsonValue(newValue);
+
+            // Use the debounced function to attempt parsing and updating parent
+            debouncedUpdateParent(newValue);
           }}
           error={jsonError}
         />
+      ) : // If schema type is object but value is not an object or is empty, and we have actual JSON data,
+      // render a simple representation of the JSON data
+      schema.type === "object" &&
+        (typeof value !== "object" ||
+          value === null ||
+          Object.keys(value).length === 0) &&
+        rawJsonValue &&
+        rawJsonValue !== "{}" ? (
+        <div className="space-y-4 border rounded-md p-4">
+          <p className="text-sm text-gray-500">
+            Form view not available for this JSON structure. Using simplified
+            view:
+          </p>
+          <pre className="bg-gray-50 dark:bg-gray-800 dark:text-gray-100 p-4 rounded text-sm overflow-auto">
+            {rawJsonValue}
+          </pre>
+          <p className="text-sm text-gray-500">
+            Use JSON mode for full editing capabilities.
+          </p>
+        </div>
       ) : (
         renderFormFields(schema, value)
       )}

client/src/components/JsonEditor.tsx

@@ -1,3 +1,4 @@
+import { useState, useEffect } from "react";
 import Editor from "react-simple-code-editor";
 import Prism from "prismjs";
 import "prismjs/components/prism-json";
@@ -10,7 +11,20 @@ interface JsonEditorProps {
   error?: string;
 }
 
-const JsonEditor = ({ value, onChange, error }: JsonEditorProps) => {
+const JsonEditor = ({
+  value,
+  onChange,
+  error: externalError,
+}: JsonEditorProps) => {
+  const [editorContent, setEditorContent] = useState(value);
+  const [internalError, setInternalError] = useState<string | undefined>(
+    undefined,
+  );
+
+  useEffect(() => {
+    setEditorContent(value);
+  }, [value]);
+
   const formatJson = (json: string): string => {
     try {
       return JSON.stringify(JSON.parse(json), null, 2);
@@ -19,25 +33,42 @@ const JsonEditor = ({ value, onChange, error }: JsonEditorProps) => {
     }
   };
 
+  const handleEditorChange = (newContent: string) => {
+    setEditorContent(newContent);
+    setInternalError(undefined);
+    onChange(newContent);
+  };
+
+  const handleFormatJson = () => {
+    try {
+      const formatted = formatJson(editorContent);
+      setEditorContent(formatted);
+      onChange(formatted);
+      setInternalError(undefined);
+    } catch (err) {
+      setInternalError(err instanceof Error ? err.message : "Invalid JSON");
+    }
+  };
+
+  const displayError = internalError || externalError;
+
   return (
     <div className="relative space-y-2">
       <div className="flex justify-end">
-        <Button
-          variant="outline"
-          size="sm"
-          onClick={() => onChange(formatJson(value))}
-        >
+        <Button variant="outline" size="sm" onClick={handleFormatJson}>
           Format JSON
         </Button>
       </div>
       <div
         className={`border rounded-md ${
-          error ? "border-red-500" : "border-gray-200 dark:border-gray-800"
+          displayError
+            ? "border-red-500"
+            : "border-gray-200 dark:border-gray-800"
         }`}
       >
         <Editor
-          value={value}
-          onValueChange={onChange}
+          value={editorContent}
+          onValueChange={handleEditorChange}
           highlight={(code) =>
             Prism.highlight(code, Prism.languages.json, "json")
           }
@@ -51,7 +82,9 @@ const JsonEditor = ({ value, onChange, error }: JsonEditorProps) => {
           className="w-full"
         />
       </div>
-      {error && <p className="text-sm text-red-500 mt-1">{error}</p>}
+      {displayError && (
+        <p className="text-sm text-red-500 mt-1">{displayError}</p>
+      )}
     </div>
   );
 };

client/src/components/Sidebar.tsx

@@ -19,6 +19,10 @@ import {
   SelectValue,
 } from "@/components/ui/select";
 import { StdErrNotification } from "@/lib/notificationTypes";
+import {
+  LoggingLevel,
+  LoggingLevelSchema,
+} from "@modelcontextprotocol/sdk/types.js";
 
 import useTheme from "../lib/useTheme";
 import { version } from "../../../package.json";
@@ -39,6 +43,9 @@ interface SidebarProps {
   setBearerToken: (token: string) => void;
   onConnect: () => void;
   stdErrNotifications: StdErrNotification[];
+  logLevel: LoggingLevel;
+  sendLogLevelRequest: (level: LoggingLevel) => void;
+  loggingSupported: boolean;
 }
 
 const Sidebar = ({
@@ -57,6 +64,9 @@ const Sidebar = ({
   setBearerToken,
   onConnect,
   stdErrNotifications,
+  logLevel,
+  sendLogLevelRequest,
+  loggingSupported,
 }: SidebarProps) => {
   const [theme, setTheme] = useTheme();
   const [showEnvVars, setShowEnvVars] = useState(false);
@@ -290,6 +300,28 @@ const Sidebar = ({
                     : "Disconnected"}
               </span>
             </div>
+
+            {loggingSupported && connectionStatus === "connected" && (
+              <div className="space-y-2">
+                <label className="text-sm font-medium">Logging Level</label>
+                <Select
+                  value={logLevel}
+                  onValueChange={(value: LoggingLevel) =>
+                    sendLogLevelRequest(value)
+                  }
+                >
+                  <SelectTrigger>
+                    <SelectValue placeholder="Select logging level" />
+                  </SelectTrigger>
+                  <SelectContent>
+                    {Object.values(LoggingLevelSchema.enum).map((level) => (
+                      <SelectItem value={level}>{level}</SelectItem>
+                    ))}
+                  </SelectContent>
+                </Select>
+              </div>
+            )}
+
             {stdErrNotifications.length > 0 && (
               <>
                 <div className="mt-4 border-t border-gray-200 pt-4">

client/src/components/ToolsTab.tsx

@@ -6,6 +6,7 @@ import { Label } from "@/components/ui/label";
 import { TabsContent } from "@/components/ui/tabs";
 import { Textarea } from "@/components/ui/textarea";
 import DynamicJsonForm, { JsonSchemaType, JsonValue } from "./DynamicJsonForm";
+import { generateDefaultValue } from "@/utils/schemaUtils";
 import {
   ListToolsResult,
   Tool,
@@ -214,7 +215,10 @@ const ToolsTab = ({
                               description: prop.description,
                               items: prop.items,
                             }}
-                            value={(params[key] as JsonValue) ?? {}}
+                            value={
+                              (params[key] as JsonValue) ??
+                              generateDefaultValue(prop)
+                            }
                             onChange={(newValue: JsonValue) => {
                               setParams({
                                 ...params,

client/src/utils/__tests__/jsonPathUtils.test.ts

@@ -0,0 +1,180 @@
+import { updateValueAtPath, getValueAtPath } from "../jsonPathUtils";
+import { JsonValue } from "../../components/DynamicJsonForm";
+
+describe("updateValueAtPath", () => {
+  // Basic functionality tests
+  test("returns the new value when path is empty", () => {
+    expect(updateValueAtPath({ foo: "bar" }, [], "newValue")).toBe("newValue");
+  });
+
+  test("initializes an empty object when input is null/undefined and path starts with a string", () => {
+    expect(updateValueAtPath(null as any, ["foo"], "bar")).toEqual({
+      foo: "bar",
+    });
+    expect(updateValueAtPath(undefined as any, ["foo"], "bar")).toEqual({
+      foo: "bar",
+    });
+  });
+
+  test("initializes an empty array when input is null/undefined and path starts with a number", () => {
+    expect(updateValueAtPath(null as any, ["0"], "bar")).toEqual(["bar"]);
+    expect(updateValueAtPath(undefined as any, ["0"], "bar")).toEqual(["bar"]);
+  });
+
+  // Object update tests
+  test("updates a simple object property", () => {
+    const obj = { name: "John", age: 30 };
+    expect(updateValueAtPath(obj, ["age"], 31)).toEqual({
+      name: "John",
+      age: 31,
+    });
+  });
+
+  test("updates a nested object property", () => {
+    const obj = { user: { name: "John", address: { city: "New York" } } };
+    expect(
+      updateValueAtPath(obj, ["user", "address", "city"], "Boston"),
+    ).toEqual({ user: { name: "John", address: { city: "Boston" } } });
+  });
+
+  test("creates missing object properties", () => {
+    const obj = { user: { name: "John" } };
+    expect(
+      updateValueAtPath(obj, ["user", "address", "city"], "Boston"),
+    ).toEqual({ user: { name: "John", address: { city: "Boston" } } });
+  });
+
+  // Array update tests
+  test("updates an array item", () => {
+    const arr = [1, 2, 3, 4];
+    expect(updateValueAtPath(arr, ["2"], 5)).toEqual([1, 2, 5, 4]);
+  });
+
+  test("extends an array when index is out of bounds", () => {
+    const arr = [1, 2, 3];
+    const result = updateValueAtPath(arr, ["5"], "new") as JsonValue[];
+
+    // Check overall array structure
+    expect(result).toEqual([1, 2, 3, null, null, "new"]);
+
+    // Explicitly verify that indices 3 and 4 contain null, not undefined
+    expect(result[3]).toBe(null);
+    expect(result[4]).toBe(null);
+
+    // Verify these aren't "holes" in the array (important distinction)
+    expect(3 in result).toBe(true);
+    expect(4 in result).toBe(true);
+
+    // Verify the array has the correct length
+    expect(result.length).toBe(6);
+
+    // Verify the array doesn't have holes by checking every index exists
+    expect(result.every((_, index: number) => index in result)).toBe(true);
+  });
+
+  test("updates a nested array item", () => {
+    const obj = { users: [{ name: "John" }, { name: "Jane" }] };
+    expect(updateValueAtPath(obj, ["users", "1", "name"], "Janet")).toEqual({
+      users: [{ name: "John" }, { name: "Janet" }],
+    });
+  });
+
+  // Error handling tests
+  test("returns original value when trying to update a primitive with a path", () => {
+    const spy = jest.spyOn(console, "error").mockImplementation();
+    const result = updateValueAtPath("string", ["foo"], "bar");
+    expect(result).toBe("string");
+    expect(spy).toHaveBeenCalled();
+    spy.mockRestore();
+  });
+
+  test("returns original array when index is invalid", () => {
+    const spy = jest.spyOn(console, "error").mockImplementation();
+    const arr = [1, 2, 3];
+    expect(updateValueAtPath(arr, ["invalid"], 4)).toEqual(arr);
+    expect(spy).toHaveBeenCalled();
+    spy.mockRestore();
+  });
+
+  test("returns original array when index is negative", () => {
+    const spy = jest.spyOn(console, "error").mockImplementation();
+    const arr = [1, 2, 3];
+    expect(updateValueAtPath(arr, ["-1"], 4)).toEqual(arr);
+    expect(spy).toHaveBeenCalled();
+    spy.mockRestore();
+  });
+
+  test("handles sparse arrays correctly by filling holes with null", () => {
+    // Create a sparse array by deleting an element
+    const sparseArr = [1, 2, 3];
+    delete sparseArr[1]; // Now sparseArr is [1, <1 empty item>, 3]
+
+    // Update a value beyond the array length
+    const result = updateValueAtPath(sparseArr, ["5"], "new") as JsonValue[];
+
+    // Check overall array structure
+    expect(result).toEqual([1, null, 3, null, null, "new"]);
+
+    // Explicitly verify that index 1 (the hole) contains null, not undefined
+    expect(result[1]).toBe(null);
+
+    // Verify this isn't a hole in the array
+    expect(1 in result).toBe(true);
+
+    // Verify all indices contain null (not undefined)
+    expect(result[1]).not.toBe(undefined);
+    expect(result[3]).toBe(null);
+    expect(result[4]).toBe(null);
+  });
+});
+
+describe("getValueAtPath", () => {
+  test("returns the original value when path is empty", () => {
+    const obj = { foo: "bar" };
+    expect(getValueAtPath(obj, [])).toBe(obj);
+  });
+
+  test("returns the value at a simple path", () => {
+    const obj = { name: "John", age: 30 };
+    expect(getValueAtPath(obj, ["name"])).toBe("John");
+  });
+
+  test("returns the value at a nested path", () => {
+    const obj = { user: { name: "John", address: { city: "New York" } } };
+    expect(getValueAtPath(obj, ["user", "address", "city"])).toBe("New York");
+  });
+
+  test("returns default value when path does not exist", () => {
+    const obj = { user: { name: "John" } };
+    expect(getValueAtPath(obj, ["user", "address", "city"], "Unknown")).toBe(
+      "Unknown",
+    );
+  });
+
+  test("returns default value when input is null/undefined", () => {
+    expect(getValueAtPath(null as any, ["foo"], "default")).toBe("default");
+    expect(getValueAtPath(undefined as any, ["foo"], "default")).toBe(
+      "default",
+    );
+  });
+
+  test("handles array indices correctly", () => {
+    const arr = ["a", "b", "c"];
+    expect(getValueAtPath(arr, ["1"])).toBe("b");
+  });
+
+  test("returns default value for out of bounds array indices", () => {
+    const arr = ["a", "b", "c"];
+    expect(getValueAtPath(arr, ["5"], "default")).toBe("default");
+  });
+
+  test("returns default value for invalid array indices", () => {
+    const arr = ["a", "b", "c"];
+    expect(getValueAtPath(arr, ["invalid"], "default")).toBe("default");
+  });
+
+  test("navigates through mixed object and array paths", () => {
+    const obj = { users: [{ name: "John" }, { name: "Jane" }] };
+    expect(getValueAtPath(obj, ["users", "1", "name"])).toBe("Jane");
+  });
+});

client/src/utils/__tests__/schemaUtils.test.ts

@@ -0,0 +1,139 @@
+import { generateDefaultValue, formatFieldLabel } from "../schemaUtils";
+import { JsonSchemaType } from "../../components/DynamicJsonForm";
+
+describe("generateDefaultValue", () => {
+  test("generates default string", () => {
+    expect(generateDefaultValue({ type: "string", required: true })).toBe("");
+  });
+
+  test("generates default number", () => {
+    expect(generateDefaultValue({ type: "number", required: true })).toBe(0);
+  });
+
+  test("generates default integer", () => {
+    expect(generateDefaultValue({ type: "integer", required: true })).toBe(0);
+  });
+
+  test("generates default boolean", () => {
+    expect(generateDefaultValue({ type: "boolean", required: true })).toBe(
+      false,
+    );
+  });
+
+  test("generates default array", () => {
+    expect(generateDefaultValue({ type: "array", required: true })).toEqual([]);
+  });
+
+  test("generates default empty object", () => {
+    expect(generateDefaultValue({ type: "object", required: true })).toEqual(
+      {},
+    );
+  });
+
+  test("generates default null for unknown types", () => {
+    // @ts-expect-error Testing with invalid type
+    expect(generateDefaultValue({ type: "unknown", required: true })).toBe(
+      null,
+    );
+  });
+
+  test("generates empty array for non-required array", () => {
+    expect(generateDefaultValue({ type: "array", required: false })).toEqual(
+      [],
+    );
+  });
+
+  test("generates empty object for non-required object", () => {
+    expect(generateDefaultValue({ type: "object", required: false })).toEqual(
+      {},
+    );
+  });
+
+  test("generates null for non-required primitive types", () => {
+    expect(generateDefaultValue({ type: "string", required: false })).toBe(
+      null,
+    );
+    expect(generateDefaultValue({ type: "number", required: false })).toBe(
+      null,
+    );
+    expect(generateDefaultValue({ type: "boolean", required: false })).toBe(
+      null,
+    );
+  });
+
+  test("generates object with properties", () => {
+    const schema: JsonSchemaType = {
+      type: "object",
+      required: true,
+      properties: {
+        name: { type: "string", required: true },
+        age: { type: "number", required: true },
+        isActive: { type: "boolean", required: true },
+      },
+    };
+    expect(generateDefaultValue(schema)).toEqual({
+      name: "",
+      age: 0,
+      isActive: false,
+    });
+  });
+
+  test("handles nested objects", () => {
+    const schema: JsonSchemaType = {
+      type: "object",
+      required: true,
+      properties: {
+        user: {
+          type: "object",
+          required: true,
+          properties: {
+            name: { type: "string", required: true },
+            address: {
+              type: "object",
+              required: true,
+              properties: {
+                city: { type: "string", required: true },
+              },
+            },
+          },
+        },
+      },
+    };
+    expect(generateDefaultValue(schema)).toEqual({
+      user: {
+        name: "",
+        address: {
+          city: "",
+        },
+      },
+    });
+  });
+
+  test("uses schema default value when provided", () => {
+    expect(generateDefaultValue({ type: "string", default: "test" })).toBe(
+      "test",
+    );
+  });
+});
+
+describe("formatFieldLabel", () => {
+  test("formats camelCase", () => {
+    expect(formatFieldLabel("firstName")).toBe("First Name");
+  });
+
+  test("formats snake_case", () => {
+    expect(formatFieldLabel("first_name")).toBe("First name");
+  });
+
+  test("formats single word", () => {
+    expect(formatFieldLabel("name")).toBe("Name");
+  });
+
+  test("formats mixed case with underscores", () => {
+    expect(formatFieldLabel("user_firstName")).toBe("User first Name");
+  });
+
+  test("handles empty string", () => {
+    expect(formatFieldLabel("")).toBe("");
+  });
+});

client/src/utils/jsonPathUtils.ts

@@ -0,0 +1,149 @@
+import { JsonValue } from "../components/DynamicJsonForm";
+
+export type JsonObject = { [key: string]: JsonValue };
+
+/**
+ * Updates a value at a specific path in a nested JSON structure
+ * @param obj The original JSON value
+ * @param path Array of keys/indices representing the path to the value
+ * @param value The new value to set
+ * @returns A new JSON value with the updated path
+ */
+export function updateValueAtPath(
+  obj: JsonValue,
+  path: string[],
+  value: JsonValue,
+): JsonValue {
+  if (path.length === 0) return value;
+
+  if (obj === null || obj === undefined) {
+    obj = !isNaN(Number(path[0])) ? [] : {};
+  }
+
+  if (Array.isArray(obj)) {
+    return updateArray(obj, path, value);
+  } else if (typeof obj === "object" && obj !== null) {
+    return updateObject(obj as JsonObject, path, value);
+  } else {
+    console.error(
+      `Cannot update path ${path.join(".")} in non-object/array value:`,
+      obj,
+    );
+    return obj;
+  }
+}
+
+/**
+ * Updates an array at a specific path
+ */
+function updateArray(
+  array: JsonValue[],
+  path: string[],
+  value: JsonValue,
+): JsonValue[] {
+  const [index, ...restPath] = path;
+  const arrayIndex = Number(index);
+
+  if (isNaN(arrayIndex)) {
+    console.error(`Invalid array index: ${index}`);
+    return array;
+  }
+
+  if (arrayIndex < 0) {
+    console.error(`Array index out of bounds: ${arrayIndex} < 0`);
+    return array;
+  }
+
+  let newArray: JsonValue[] = [];
+  for (let i = 0; i < array.length; i++) {
+    newArray[i] = i in array ? array[i] : null;
+  }
+
+  if (arrayIndex >= newArray.length) {
+    const extendedArray: JsonValue[] = new Array(arrayIndex).fill(null);
+    // Copy over the existing elements (now guaranteed to be dense)
+    for (let i = 0; i < newArray.length; i++) {
+      extendedArray[i] = newArray[i];
+    }
+    newArray = extendedArray;
+  }
+
+  if (restPath.length === 0) {
+    newArray[arrayIndex] = value;
+  } else {
+    newArray[arrayIndex] = updateValueAtPath(
+      newArray[arrayIndex],
+      restPath,
+      value,
+    );
+  }
+  return newArray;
+}
+
+/**
+ * Updates an object at a specific path
+ */
+function updateObject(
+  obj: JsonObject,
+  path: string[],
+  value: JsonValue,
+): JsonObject {
+  const [key, ...restPath] = path;
+
+  // Validate object key
+  if (typeof key !== "string") {
+    console.error(`Invalid object key: ${key}`);
+    return obj;
+  }
+
+  const newObj = { ...obj };
+
+  if (restPath.length === 0) {
+    newObj[key] = value;
+  } else {
+    // Ensure key exists
+    if (!(key in newObj)) {
+      newObj[key] = {};
+    }
+    newObj[key] = updateValueAtPath(newObj[key], restPath, value);
+  }
+  return newObj;
+}
+
+/**
+ * Gets a value at a specific path in a nested JSON structure
+ * @param obj The JSON value to traverse
+ * @param path Array of keys/indices representing the path to the value
+ * @param defaultValue Value to return if path doesn't exist
+ * @returns The value at the path, or defaultValue if not found
+ */
+export function getValueAtPath(
+  obj: JsonValue,
+  path: string[],
+  defaultValue: JsonValue = null,
+): JsonValue {
+  if (path.length === 0) return obj;
+
+  const [first, ...rest] = path;
+
+  if (obj === null || obj === undefined) {
+    return defaultValue;
+  }
+
+  if (Array.isArray(obj)) {
+    const index = Number(first);
+    if (isNaN(index) || index < 0 || index >= obj.length) {
+      return defaultValue;
+    }
+    return getValueAtPath(obj[index], rest, defaultValue);
+  }
+
+  if (typeof obj === "object" && obj !== null) {
+    if (!(first in obj)) {
+      return defaultValue;
+    }
+    return getValueAtPath((obj as JsonObject)[first], rest, defaultValue);
+  }
+
+  return defaultValue;
+}

client/src/utils/schemaUtils.ts

@@ -0,0 +1,57 @@
+import { JsonValue, JsonSchemaType } from "../components/DynamicJsonForm";
+import { JsonObject } from "./jsonPathUtils";
+
+/**
+ * Generates a default value based on a JSON schema type
+ * @param schema The JSON schema definition
+ * @returns A default value matching the schema type, or null for non-required fields
+ */
+export function generateDefaultValue(schema: JsonSchemaType): JsonValue {
+  if ("default" in schema) {
+    return schema.default;
+  }
+
+  if (!schema.required) {
+    if (schema.type === "array") return [];
+    if (schema.type === "object") return {};
+    return null;
+  }
+
+  switch (schema.type) {
+    case "string":
+      return "";
+    case "number":
+    case "integer":
+      return 0;
+    case "boolean":
+      return false;
+    case "array":
+      return [];
+    case "object": {
+      if (!schema.properties) return {};
+
+      const obj: JsonObject = {};
+      Object.entries(schema.properties)
+        .filter(([, prop]) => prop.required)
+        .forEach(([key, prop]) => {
+          const value = generateDefaultValue(prop);
+          obj[key] = value;
+        });
+      return obj;
+    }
+    default:
+      return null;
+  }
+}
+
+/**
+ * Formats a field key into a human-readable label
+ * @param key The field key to format
+ * @returns A formatted label string
+ */
+export function formatFieldLabel(key: string): string {
+  return key
+    .replace(/([A-Z])/g, " $1") // Insert space before capital letters
+    .replace(/_/g, " ") // Replace underscores with spaces
+    .replace(/^\w/, (c) => c.toUpperCase()); // Capitalize first letter
+}

client/tsconfig.jest.json

@@ -0,0 +1,10 @@
+{
+  "extends": "./tsconfig.app.json",
+  "compilerOptions": {
+    "jsx": "react-jsx",
+    "esModuleInterop": true,
+    "module": "ESNext",
+    "moduleResolution": "node"
+  },
+  "include": ["src"]
+}