Implementation of SEP-986: Specify Format for Tool Names

src/server/mcp.test.ts

@@ -227,6 +227,10 @@ describe('ResourceTemplate', () => {
 });
 
 describe('tool()', () => {
+    afterEach(() => {
+        jest.restoreAllMocks();
+    });
+
     /***
      * Test: Zero-Argument Tool Registration
      */
@@ -1692,6 +1696,56 @@ describe('tool()', () => {
         expect(result.tools[0].name).toBe('test-without-meta');
         expect(result.tools[0]._meta).toBeUndefined();
     });
+
+    test('should validate tool names according to SEP specification', () => {
+        // Create a new server instance for this test
+        const testServer = new McpServer({
+            name: 'test server',
+            version: '1.0'
+        });
+
+        // Spy on console.warn to verify warnings are logged
+        const warnSpy = jest.spyOn(console, 'warn').mockImplementation();
+
+        // Test valid tool names
+        testServer.registerTool(
+            'valid-tool-name',
+            {
+                description: 'A valid tool name'
+            },
+            async () => ({ content: [{ type: 'text' as const, text: 'Success' }] })
+        );
+
+        // Test tool name with warnings (starts with dash)
+        testServer.registerTool(
+            '-warning-tool',
+            {
+                description: 'A tool name that generates warnings'
+            },
+            async () => ({ content: [{ type: 'text' as const, text: 'Success' }] })
+        );
+
+        // Test invalid tool name (contains spaces)
+        testServer.registerTool(
+            'invalid tool name',
+            {
+                description: 'An invalid tool name'
+            },
+            async () => ({ content: [{ type: 'text' as const, text: 'Success' }] })
+        );
+
+        // Verify that warnings were issued (both for warnings and validation failures)
+        expect(warnSpy).toHaveBeenCalled();
+
+        // Verify specific warning content
+        const warningCalls = warnSpy.mock.calls.map(call => call.join(' '));
+        expect(warningCalls.some(call => call.includes('Tool name starts or ends with a dash'))).toBe(true);
+        expect(warningCalls.some(call => call.includes('Tool name contains spaces'))).toBe(true);
+        expect(warningCalls.some(call => call.includes('Tool name contains invalid characters'))).toBe(true);
+
+        // Clean up spies
+        warnSpy.mockRestore();
+    });
 });
 
 describe('resource()', () => {

src/server/mcp.ts

@@ -40,6 +40,7 @@ import { Completable, CompletableDef } from './completable.js';
 import { UriTemplate, Variables } from '../shared/uriTemplate.js';
 import { RequestHandlerExtra } from '../shared/protocol.js';
 import { Transport } from '../shared/transport.js';
+import { validateAndWarnToolName } from '../shared/toolNameValidation.js';
 
 /**
  * High-level MCP server that provides a simpler API for working with resources, tools, and prompts.
@@ -664,6 +665,9 @@ export class McpServer {
         _meta: Record<string, unknown> | undefined,
         callback: ToolCallback<ZodRawShape | undefined>
     ): RegisteredTool {
+        // Validate tool name according to SEP specification
+        validateAndWarnToolName(name);
+
         const registeredTool: RegisteredTool = {
             title,
             description,
@@ -678,6 +682,9 @@ export class McpServer {
             remove: () => registeredTool.update({ name: null }),
             update: updates => {
                 if (typeof updates.name !== 'undefined' && updates.name !== name) {
+                    if (typeof updates.name === 'string') {
+                        validateAndWarnToolName(updates.name);
+                    }
                     delete this._registeredTools[name];
                     if (updates.name) this._registeredTools[updates.name] = registeredTool;
                 }

src/shared/toolNameValidation.test.ts

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