refactor: disable tools instead of not registering them (#2636)

src/ToolHandler.ts

@@ -169,7 +169,7 @@ export class ToolHandler {
     zod.ZodRawShape,
     zod.core.$loose
   >;
-  readonly shouldRegister: boolean;
+  readonly disabled: boolean;
   private readonly disabledReason?: string;
 
   constructor(
@@ -180,7 +180,7 @@ export class ToolHandler {
   ) {
     const {disabled, reason} = getToolStatusInfo(tool, serverArgs);
     this.disabledReason = reason;
-    this.shouldRegister = !(disabled && !serverArgs.viaCli);
+    this.disabled = disabled && !serverArgs.viaCli;
 
     this.inputSchema = tool.schema;
     this.registeredInputSchema = zod.object(this.inputSchema).loose();
@@ -192,7 +192,9 @@ export class ToolHandler {
     );
   }
 
-  async handle(params: Record<string, unknown>): Promise<CallToolResult> {
+  handle = async (params: Record<string, unknown>): Promise<CallToolResult> => {
+    using _guard = await this.toolMutex.acquire();
+
     if (this.disabledReason) {
       return {
         content: [
@@ -222,7 +224,6 @@ export class ToolHandler {
       };
     }
 
-    const guard = await this.toolMutex.acquire();
     const startTime = Date.now();
     let success = false;
     let devToolsData: DevToolsData | undefined;
@@ -329,7 +330,6 @@ export class ToolHandler {
         devToolsData,
         pageUrl,
       });
-      guard[Symbol.dispose]();
     }
-  }
+  };
 }

src/index.ts

@@ -294,21 +294,19 @@ export class McpServer {
       this.#toolMutex,
     );
 
-    if (!toolHandler.shouldRegister) {
-      return;
-    }
-
-    this.server.registerTool(
+    const registeredTool = this.server.registerTool(
       tool.name,
       {
         description: tool.description,
         inputSchema: toolHandler.registeredInputSchema,
         annotations: tool.annotations,
       },
-      async params => {
-        return await toolHandler.handle(params);
-      },
+      toolHandler.handle,
     );
+
+    if (toolHandler.disabled) {
+      registeredTool.disable();
+    }
   }
 }
 

src/third_party/index.ts

@@ -18,7 +18,7 @@ export type {Options as YargsOptions} from 'yargs';
 export {default as yargs} from 'yargs';
 export {hideBin} from 'yargs/helpers';
 export {default as semver} from 'semver';
-export {McpServer} from '@modelcontextprotocol/server';
+export {McpServer, type RegisteredTool} from '@modelcontextprotocol/server';
 export {
   StdioServerTransport,
   serveStdio,

src/tools/tools.ts

@@ -56,9 +56,7 @@ export const createTools = (args: ParsedArguments) => {
     tools.push(tool(args));
   }
 
-  tools.sort((a, b) => {
-    return a.name.localeCompare(b.name);
-  });
+  tools.sort((a, b) => a.name.localeCompare(b.name));
 
   return tools;
 };

tests/ToolHandler.test.ts

@@ -70,7 +70,7 @@ describe('ToolHandler', () => {
       toolMutex,
     );
 
-    assert.strictEqual(toolHandler.shouldRegister, true);
+    assert.strictEqual(toolHandler.disabled, false);
     await toolHandler.handle({pageId: 1});
 
     assert.strictEqual(mockContext.getPageById.calledOnce, true);
@@ -115,7 +115,7 @@ describe('ToolHandler', () => {
       toolMutex,
     );
 
-    assert.strictEqual(toolHandler.shouldRegister, true);
+    assert.strictEqual(toolHandler.disabled, false);
     await toolHandler.handle({});
 
     assert.strictEqual(mockContext.getSelectedMcpPage.calledOnce, true);
@@ -155,7 +155,7 @@ describe('ToolHandler', () => {
       toolMutex,
     );
 
-    assert.strictEqual(toolHandler.shouldRegister, true);
+    assert.strictEqual(toolHandler.disabled, false);
     const result = await toolHandler.handle({});
 
     assert.strictEqual(mockContext.getDevToolsData.calledOnce, true);
@@ -300,7 +300,7 @@ describe('ToolHandler', () => {
     assert.strictEqual(handlerCalled, false);
   });
 
-  it('sets shouldRegister to false and returns disabled reason when category is disabled', async () => {
+  it('sets disabled to true and returns disabled reason when category is disabled', async () => {
     let handlerCalled = false;
     const tool: ToolDefinition = {
       name: 'disabled_tool',
@@ -332,7 +332,7 @@ describe('ToolHandler', () => {
       toolMutex,
     );
 
-    assert.strictEqual(toolHandler.shouldRegister, false);
+    assert.strictEqual(toolHandler.disabled, true);
 
     const result = await toolHandler.handle({});
     assert.strictEqual(result.isError, true);
@@ -362,7 +362,7 @@ describe('ToolHandler', () => {
       async () => mockContext,
       toolMutex,
     );
-    assert.strictEqual(defaultHandler.shouldRegister, true);
+    assert.strictEqual(defaultHandler.disabled, false);
 
     const disabledServerArgs = parseArguments(
       '1.0.0',
@@ -381,7 +381,7 @@ describe('ToolHandler', () => {
       async () => mockContext,
       toolMutex,
     );
-    assert.strictEqual(disabledHandler.shouldRegister, false);
+    assert.strictEqual(disabledHandler.disabled, true);
 
     const disabledResult = await disabledHandler.handle({function: '() => 1'});
     assert.strictEqual(disabledResult.isError, true);
@@ -409,7 +409,7 @@ describe('ToolHandler', () => {
       async () => mockContext,
       toolMutex,
     );
-    assert.strictEqual(cliHandler.shouldRegister, true);
+    assert.strictEqual(cliHandler.disabled, false);
     const cliResult = await cliHandler.handle({function: '() => 1'});
     assert.strictEqual(cliResult.isError, true);
     assert.match(
@@ -439,7 +439,7 @@ describe('ToolHandler', () => {
       async () => mockContext,
       toolMutex,
     );
-    assert.strictEqual(defaultHandler.shouldRegister, true);
+    assert.strictEqual(defaultHandler.disabled, false);
 
     const disabledServerArgs = parseArguments(
       '1.0.0',
@@ -458,7 +458,7 @@ describe('ToolHandler', () => {
       async () => mockContext,
       toolMutex,
     );
-    assert.strictEqual(disabledHandler.shouldRegister, false);
+    assert.strictEqual(disabledHandler.disabled, true);
   });
 
   it('validates files specified in verifyFilesSchema and rewrites input with validated paths/URLs', async () => {