fix: update tool name validation to enforce 1-64 character length limit

- Adjusted validation logic and regex to accept tool names between 1 and 64 characters
- Updated test cases to reflect new character length requirements
- Modified warnings to align with the updated maximum length

modelcontextprotocol/modelcontextprotocol#986 (comment)

Author: kentcdodds

src/shared/toolNameValidation.test.ts

@@ -55,8 +55,8 @@ describe('validateToolName', () => {
       expect(result.warnings).toHaveLength(0);
     });
 
-    test('should accept 128 character names', () => {
-      const name = 'a'.repeat(128);
+    test('should accept 64 character names', () => {
+      const name = 'a'.repeat(64);
       const result = validateToolName(name);
       expect(result.isValid).toBe(true);
       expect(result.warnings).toHaveLength(0);
@@ -70,11 +70,11 @@ describe('validateToolName', () => {
       expect(result.warnings).toContain('Tool name cannot be empty');
     });
 
-    test('should reject names longer than 128 characters', () => {
-      const name = 'a'.repeat(129);
+    test('should reject names longer than 64 characters', () => {
+      const name = 'a'.repeat(65);
       const result = validateToolName(name);
       expect(result.isValid).toBe(false);
-      expect(result.warnings).toContain('Tool name exceeds maximum length of 128 characters (current: 129)');
+      expect(result.warnings).toContain('Tool name exceeds maximum length of 64 characters (current: 129)');
     });
 
     test('should reject names with spaces', () => {

src/shared/toolNameValidation.ts

@@ -1,7 +1,7 @@
 /**
  * Tool name validation utilities according to SEP: Specify Format for Tool Names
  * 
- * Tool names SHOULD be between 1 and 128 characters in length (inclusive).
+ * Tool names SHOULD be between 1 and 64 characters in length (inclusive).
  * Tool names are case-sensitive.
  * Allowed characters: uppercase and lowercase ASCII letters (A-Z, a-z), digits
  * (0-9), underscore (_), dash (-), dot (.), and forward slash (/).
@@ -11,7 +11,7 @@
 /**
  * Regular expression for valid tool names according to SEP-986 specification
  */
-const TOOL_NAME_REGEX = /^[A-Za-z0-9._/-]{1,128}$/;
+const TOOL_NAME_REGEX = /^[A-Za-z0-9._/-]{1,64}$/;
 
 /**
  * Validates a tool name according to the SEP specification
@@ -32,10 +32,10 @@ export function validateToolName(name: string): {
     };
   }
 
-  if (name.length > 128) {
+  if (name.length > 64) {
     return {
       isValid: false,
-      warnings: [`Tool name exceeds maximum length of 128 characters (current: ${name.length})`]
+      warnings: [`Tool name exceeds maximum length of 64 characters (current: ${name.length})`]
     };
   }