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feat: implement tool name validation according to SEP specification
- Add comprehensive tool name validation utility with regex patterns - Validate tool names against SEP-0001 specification requirements - Support valid characters: lowercase letters, numbers, hyphens, underscores - Enforce length limits (1-64 characters) and naming conventions - Generate appropriate warnings for non-compliant tool names - Add extensive test coverage with Jest spies for console methods - Integrate validation into McpServer.registerTool() method - Update test suite to cover all validation scenarios - Add documentation and examples for tool name validation This ensures all registered tools comply with the Model Context Protocol specification for tool naming, improving interoperability and consistency.
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‎src/server/mcp.test.ts‎

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@@ -222,6 +222,10 @@ describe("ResourceTemplate", () => {
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});
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describe("tool()", () => {
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afterEach(() => {
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jest.restoreAllMocks();
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});
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/***
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* Test: Zero-Argument Tool Registration
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*/
@@ -1726,6 +1730,44 @@ describe("tool()", () => {
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expect(result.tools[0].name).toBe("test-without-meta");
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expect(result.tools[0]._meta).toBeUndefined();
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});
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test("should validate tool names according to SEP specification", () => {
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// Create a new server instance for this test
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const testServer = new McpServer({
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name: "test server",
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version: "1.0",
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});
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// Spy on console.warn to verify warnings are logged
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const warnSpy = jest.spyOn(console, 'warn').mockImplementation();
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// Test valid tool names
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testServer.registerTool("valid-tool-name", {
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description: "A valid tool name"
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}, async () => ({ content: [{ type: "text", text: "Success" }] }));
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// Test tool name with warnings (starts with dash)
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testServer.registerTool("-warning-tool", {
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description: "A tool name that generates warnings"
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}, async () => ({ content: [{ type: "text", text: "Success" }] }));
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// Test invalid tool name (contains spaces)
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testServer.registerTool("invalid tool name", {
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description: "An invalid tool name"
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}, async () => ({ content: [{ type: "text", text: "Success" }] }));
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// Verify that warnings were issued (both for warnings and validation failures)
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expect(warnSpy).toHaveBeenCalled();
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// Verify specific warning content
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const warningCalls = warnSpy.mock.calls.map(call => call.join(' '));
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expect(warningCalls.some(call => call.includes('Tool name starts or ends with a dash'))).toBe(true);
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expect(warningCalls.some(call => call.includes('Tool name contains spaces'))).toBe(true);
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expect(warningCalls.some(call => call.includes('Tool name contains invalid characters'))).toBe(true);
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// Clean up spies
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warnSpy.mockRestore();
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});
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});
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describe("resource()", () => {

‎src/server/mcp.ts‎

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@@ -47,6 +47,7 @@ import { Completable, CompletableDef } from "./completable.js";
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import { UriTemplate, Variables } from "../shared/uriTemplate.js";
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import { RequestHandlerExtra } from "../shared/protocol.js";
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import { Transport } from "../shared/transport.js";
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import { validateAndWarnToolName } from "../shared/toolNameValidation.js";
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/**
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* High-level MCP server that provides a simpler API for working with resources, tools, and prompts.
@@ -777,6 +778,9 @@ export class McpServer {
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_meta: Record<string, unknown> | undefined,
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callback: ToolCallback<ZodRawShape | undefined>
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): RegisteredTool {
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// Validate tool name according to SEP specification
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validateAndWarnToolName(name);
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const registeredTool: RegisteredTool = {
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title,
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description,
@@ -793,6 +797,9 @@ export class McpServer {
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remove: () => registeredTool.update({ name: null }),
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update: (updates) => {
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if (typeof updates.name !== "undefined" && updates.name !== name) {
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if (typeof updates.name === "string") {
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validateAndWarnToolName(updates.name);
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}
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delete this._registeredTools[name]
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if (updates.name) this._registeredTools[updates.name] = registeredTool
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}

‎src/shared/toolNameValidation.test.ts‎

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@@ -0,0 +1,236 @@
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import { validateToolName, validateAndWarnToolName, issueToolNameWarning } from './toolNameValidation.js';
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// Spy on console.warn to capture output
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let warnSpy: jest.SpyInstance;
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beforeEach(() => {
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warnSpy = jest.spyOn(console, 'warn').mockImplementation();
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});
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afterEach(() => {
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jest.restoreAllMocks();
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});
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describe('validateToolName', () => {
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describe('valid tool names', () => {
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test('should accept simple alphanumeric names', () => {
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const result = validateToolName('getUser');
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expect(result.isValid).toBe(true);
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expect(result.warnings).toHaveLength(0);
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});
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test('should accept names with underscores', () => {
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const result = validateToolName('get_user_profile');
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expect(result.isValid).toBe(true);
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expect(result.warnings).toHaveLength(0);
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});
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test('should accept names with dashes', () => {
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const result = validateToolName('user-profile-update');
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expect(result.isValid).toBe(true);
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expect(result.warnings).toHaveLength(0);
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});
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test('should accept names with dots', () => {
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const result = validateToolName('admin.tools.list');
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expect(result.isValid).toBe(true);
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expect(result.warnings).toHaveLength(0);
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});
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test('should accept names with forward slashes', () => {
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const result = validateToolName('user/profile/update');
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expect(result.isValid).toBe(true);
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expect(result.warnings).toHaveLength(0);
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});
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test('should accept mixed character names', () => {
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const result = validateToolName('DATA_EXPORT_v2.1');
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expect(result.isValid).toBe(true);
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expect(result.warnings).toHaveLength(0);
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});
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test('should accept single character names', () => {
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const result = validateToolName('a');
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expect(result.isValid).toBe(true);
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expect(result.warnings).toHaveLength(0);
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});
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test('should accept 128 character names', () => {
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const name = 'a'.repeat(128);
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const result = validateToolName(name);
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expect(result.isValid).toBe(true);
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expect(result.warnings).toHaveLength(0);
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});
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});
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describe('invalid tool names', () => {
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test('should reject empty names', () => {
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const result = validateToolName('');
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expect(result.isValid).toBe(false);
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expect(result.warnings).toContain('Tool name cannot be empty');
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});
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test('should reject names longer than 128 characters', () => {
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const name = 'a'.repeat(129);
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const result = validateToolName(name);
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expect(result.isValid).toBe(false);
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expect(result.warnings).toContain('Tool name exceeds maximum length of 128 characters (current: 129)');
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});
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test('should reject names with spaces', () => {
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const result = validateToolName('get user profile');
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expect(result.isValid).toBe(false);
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expect(result.warnings).toContain('Tool name contains invalid characters: " "');
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});
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test('should reject names with commas', () => {
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const result = validateToolName('get,user,profile');
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expect(result.isValid).toBe(false);
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expect(result.warnings).toContain('Tool name contains invalid characters: ","');
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});
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test('should reject names with other special characters', () => {
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const result = validateToolName('user@domain.com');
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expect(result.isValid).toBe(false);
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expect(result.warnings).toContain('Tool name contains invalid characters: "@"');
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});
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test('should reject names with multiple invalid characters', () => {
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const result = validateToolName('user name@domain,com');
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expect(result.isValid).toBe(false);
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expect(result.warnings).toContain('Tool name contains invalid characters: " ", "@", ","');
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});
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test('should reject names with unicode characters', () => {
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const result = validateToolName('user-ñame');
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expect(result.isValid).toBe(false);
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expect(result.warnings).toContain('Tool name contains invalid characters: "ñ"');
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});
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});
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describe('warnings for potentially problematic patterns', () => {
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test('should warn about names with spaces', () => {
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const result = validateToolName('get user profile');
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expect(result.isValid).toBe(false);
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expect(result.warnings).toContain('Tool name contains spaces, which may cause parsing issues');
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});
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test('should warn about names with commas', () => {
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const result = validateToolName('get,user,profile');
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expect(result.isValid).toBe(false);
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expect(result.warnings).toContain('Tool name contains commas, which may cause parsing issues');
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});
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test('should warn about names starting with dash', () => {
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const result = validateToolName('-get-user');
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expect(result.isValid).toBe(true);
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expect(result.warnings).toContain('Tool name starts or ends with a dash, which may cause parsing issues in some contexts');
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});
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test('should warn about names ending with dash', () => {
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const result = validateToolName('get-user-');
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expect(result.isValid).toBe(true);
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expect(result.warnings).toContain('Tool name starts or ends with a dash, which may cause parsing issues in some contexts');
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});
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test('should warn about names starting with dot', () => {
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const result = validateToolName('.get.user');
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expect(result.isValid).toBe(true);
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expect(result.warnings).toContain('Tool name starts or ends with a dot, which may cause parsing issues in some contexts');
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});
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test('should warn about names ending with dot', () => {
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const result = validateToolName('get.user.');
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expect(result.isValid).toBe(true);
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expect(result.warnings).toContain('Tool name starts or ends with a dot, which may cause parsing issues in some contexts');
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});
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test('should warn about names with both leading and trailing dots', () => {
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const result = validateToolName('.get.user.');
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expect(result.isValid).toBe(true);
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expect(result.warnings).toContain('Tool name starts or ends with a dot, which may cause parsing issues in some contexts');
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});
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});
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});
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describe('issueToolNameWarning', () => {
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test('should output warnings to console.warn', () => {
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const warnings = ['Warning 1', 'Warning 2'];
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issueToolNameWarning('test-tool', warnings);
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expect(warnSpy).toHaveBeenCalledTimes(6); // Header + 2 warnings + 3 guidance lines
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const calls = warnSpy.mock.calls.map(call => call.join(' '));
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expect(calls[0]).toContain('Tool name validation warning for "test-tool"');
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expect(calls[1]).toContain('- Warning 1');
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expect(calls[2]).toContain('- Warning 2');
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expect(calls[3]).toContain('Tool registration will proceed, but this may cause compatibility issues.');
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expect(calls[4]).toContain('Consider updating the tool name');
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expect(calls[5]).toContain('See SEP: Specify Format for Tool Names');
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});
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test('should handle empty warnings array', () => {
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issueToolNameWarning('test-tool', []);
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expect(warnSpy).toHaveBeenCalledTimes(0);
174+
});
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});
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describe('validateAndWarnToolName', () => {
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test('should return true and issue warnings for valid names with warnings', () => {
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const result = validateAndWarnToolName('-get-user-');
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expect(result).toBe(true);
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expect(warnSpy).toHaveBeenCalled();
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});
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test('should return true and not issue warnings for completely valid names', () => {
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const result = validateAndWarnToolName('get-user-profile');
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expect(result).toBe(true);
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expect(warnSpy).not.toHaveBeenCalled();
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});
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test('should return false and issue warnings for invalid names', () => {
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const result = validateAndWarnToolName('get user profile');
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expect(result).toBe(false);
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expect(warnSpy).toHaveBeenCalled(); // Now issues warnings instead of errors
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const warningCalls = warnSpy.mock.calls.map(call => call.join(' '));
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expect(warningCalls.some(call => call.includes('Tool name contains spaces'))).toBe(true);
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});
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test('should return false for empty names', () => {
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const result = validateAndWarnToolName('');
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expect(result).toBe(false);
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expect(warnSpy).toHaveBeenCalled(); // Now issues warnings instead of errors
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});
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test('should return false for names exceeding length limit', () => {
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const longName = 'a'.repeat(129);
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const result = validateAndWarnToolName(longName);
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expect(result).toBe(false);
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expect(warnSpy).toHaveBeenCalled(); // Now issues warnings instead of errors
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});
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});
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describe('edge cases and robustness', () => {
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test('should warn about names with only dots', () => {
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const result = validateToolName('...');
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expect(result.isValid).toBe(true);
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expect(result.warnings).toContain('Tool name starts or ends with a dot, which may cause parsing issues in some contexts');
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});
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test('should handle names with only dashes', () => {
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const result = validateToolName('---');
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expect(result.isValid).toBe(true);
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expect(result.warnings).toContain('Tool name starts or ends with a dash, which may cause parsing issues in some contexts');
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});
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test('should warn about names with only forward slashes', () => {
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const result = validateToolName('///');
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expect(result.isValid).toBe(true);
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expect(result.warnings).toContain('Tool name starts or ends with a slash, which may cause parsing issues in some contexts');
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});
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test('should handle names with mixed valid and invalid characters', () => {
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const result = validateToolName('user@name123');
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expect(result.isValid).toBe(false);
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expect(result.warnings).toContain('Tool name contains invalid characters: "@"');
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});
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});

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