chore: make tool definition arguments optional

Author: nroscino

src/McpContext.ts

@@ -53,9 +53,9 @@ export interface TextSnapshotNode extends SerializedAXNode {
 }
 
 export interface ExtensionServiceWorker {
-	url: string;
-	target: Target;
-	id: string;
+  url: string;
+  target: Target;
+  id: string;
 }
 
 export interface GeolocationOptions {
@@ -156,8 +156,8 @@ export class McpContext implements Context {
   #pageIdMap = new WeakMap<Page, number>();
   #nextPageId = 1;
 
-	#extensionServiceWorkerMap = new WeakMap<Target, string>();
-	#nextExtensionServiceWorkerId = 1;
+  #extensionServiceWorkerMap = new WeakMap<Target, string>();
+  #nextExtensionServiceWorkerId = 1;
 
   #nextSnapshotId = 1;
   #traceResults: TraceResult[] = [];
@@ -508,7 +508,7 @@ export class McpContext implements Context {
     }
     if (page.isClosed()) {
       throw new Error(
-        `The selected page has been closed. Call ${listPages({} as ParsedArguments).name} to see open pages.`,
+        `The selected page has been closed. Call ${listPages().name} to see open pages.`,
       );
     }
     return page;
@@ -598,40 +598,40 @@ export class McpContext implements Context {
     }
   }
 
-	/**
-	 * Creates a snapshot of the extension service workers.
-	 */
-	async createExtensionServiceWorkersSnapshot(): Promise<
-		ExtensionServiceWorker[]
-	> {
-		const allTargets = await this.browser.targets();
-
-		const serviceWorkers = allTargets.filter(target => {
-			return (
-				target.type() === 'service_worker' &&
-				target.url().includes('chrome-extension://')
-			);
-		});
-
-		for (const serviceWorker of serviceWorkers) {
-			if (!this.#extensionServiceWorkerMap.has(serviceWorker)) {
-				this.#extensionServiceWorkerMap.set(
-					serviceWorker,
-					'sw-' + this.#nextExtensionServiceWorkerId++,
-				);
-			}
-		}
-
-		this.#extensionServiceWorkers = serviceWorkers.map(serviceWorker => {
-			return {
-				target: serviceWorker,
-				id: this.#extensionServiceWorkerMap.get(serviceWorker)!,
-				url: serviceWorker.url(),
-			};
-		});
-
-		return this.#extensionServiceWorkers;
-	}
+  /**
+   * Creates a snapshot of the extension service workers.
+   */
+  async createExtensionServiceWorkersSnapshot(): Promise<
+    ExtensionServiceWorker[]
+  > {
+    const allTargets = await this.browser.targets();
+
+    const serviceWorkers = allTargets.filter(target => {
+      return (
+        target.type() === 'service_worker' &&
+        target.url().includes('chrome-extension://')
+      );
+    });
+
+    for (const serviceWorker of serviceWorkers) {
+      if (!this.#extensionServiceWorkerMap.has(serviceWorker)) {
+        this.#extensionServiceWorkerMap.set(
+          serviceWorker,
+          'sw-' + this.#nextExtensionServiceWorkerId++,
+        );
+      }
+    }
+
+    this.#extensionServiceWorkers = serviceWorkers.map(serviceWorker => {
+      return {
+        target: serviceWorker,
+        id: this.#extensionServiceWorkerMap.get(serviceWorker)!,
+        url: serviceWorker.url(),
+      };
+    });
+
+    return this.#extensionServiceWorkers;
+  }
 
   async createPagesSnapshot(): Promise<Page[]> {
     const allPages = await this.#getAllPages();
@@ -726,15 +726,15 @@ export class McpContext implements Context {
     }
   }
 
-	getExtensionServiceWorkers(): ExtensionServiceWorker[] {
-		return this.#extensionServiceWorkers;
-	}
+  getExtensionServiceWorkers(): ExtensionServiceWorker[] {
+    return this.#extensionServiceWorkers;
+  }
 
-	getExtensionServiceWorkerId(
-		extensionServiceWorker: ExtensionServiceWorker,
-	): string | undefined {
-		return this.#extensionServiceWorkerMap.get(extensionServiceWorker.target);
-	}
+  getExtensionServiceWorkerId(
+    extensionServiceWorker: ExtensionServiceWorker,
+  ): string | undefined {
+    return this.#extensionServiceWorkerMap.get(extensionServiceWorker.target);
+  }
 
   getPages(): Page[] {
     return this.#pages;

src/tools/ToolDefinition.ts

@@ -165,14 +165,16 @@ export function defineTool<
   Schema extends zod.ZodRawShape,
   Args extends ParsedArguments = ParsedArguments,
 >(
-  definition: (args: Args) => ToolDefinition<Schema>,
-): (args: Args) => ToolDefinition<Schema>;
+  definition: (args?: Args) => ToolDefinition<Schema>,
+): (args?: Args) => ToolDefinition<Schema>;
 
 export function defineTool<
   Schema extends zod.ZodRawShape,
   Args extends ParsedArguments = ParsedArguments,
 >(
-  definition: ToolDefinition<Schema> | ((args: Args) => ToolDefinition<Schema>),
+  definition:
+    | ToolDefinition<Schema>
+    | ((args?: Args) => ToolDefinition<Schema>),
 ) {
   return definition;
 }

src/tools/pages.ts

@@ -12,18 +12,18 @@ import {zod} from '../third_party/index.js';
 import {ToolCategory} from './categories.js';
 import {CLOSE_PAGE_ERROR, defineTool, timeoutSchema} from './ToolDefinition.js';
 
-export const listPages = defineTool((args) => {
+export const listPages = defineTool(args => {
   return {
     name: 'list_pages',
-    description: `Get a list of pages ${args.categoryExtensions ? 'including extension service workers' : ''} open in the browser.`,
+    description: `Get a list of pages ${args?.categoryExtensions ? 'including extension service workers' : ''} open in the browser.`,
     annotations: {
       category: ToolCategory.NAVIGATION,
       readOnlyHint: true,
     },
     schema: {},
     handler: async (_request, response) => {
       response.setIncludePages(true);
-      if(args.categoryExtensions) {
+      if (args?.categoryExtensions) {
         response.setIncludeExtensionServiceWorkers(true);
       }
     },
@@ -41,7 +41,7 @@ export const selectPage = defineTool({
     pageId: zod
       .number()
       .describe(
-        `The ID of the page to select. Call ${listPages({} as ParsedArguments).name} to get available pages.`,
+        `The ID of the page to select. Call ${listPages().name} to get available pages.`,
       ),
     bringToFront: zod
       .boolean()
@@ -378,7 +378,7 @@ export const getTabId = defineTool({
     pageId: zod
       .number()
       .describe(
-        `The ID of the page to get the tab ID for. Call ${listPages({} as ParsedArguments).name} to get available pages.`,
+        `The ID of the page to get the tab ID for. Call ${listPages().name} to get available pages.`,
       ),
   },
   handler: async (request, response, context) => {

tests/tools/pages.test.ts

@@ -38,11 +38,7 @@ describe('pages', () => {
   describe('list_pages', () => {
     it('list pages', async () => {
       await withMcpContext(async (response, context) => {
-        await listPages({} as ParsedArguments).handler(
-          {params: {}},
-          response,
-          context,
-        );
+        await listPages().handler({params: {}}, response, context);
         assert.ok(response.includePages);
       });
     });
@@ -64,7 +60,9 @@ describe('pages', () => {
 
           response.resetResponseLineForTesting();
 
-          const listPageDef = listPages({categoryExtensions} as ParsedArguments);
+          const listPageDef = listPages({
+            categoryExtensions,
+          } as ParsedArguments);
           await listPageDef.handler({params: {}}, response, context);
 
           const result = await response.handle(listPageDef.name, context);