chore: mcp backend switcher (#854)

src/browserServerBackend.ts

@@ -15,7 +15,6 @@
  */
 
 import { fileURLToPath } from 'url';
-import { z } from 'zod';
 import { FullConfig } from './config.js';
 import { Context } from './context.js';
 import { logUnhandledError } from './log.js';
@@ -23,17 +22,12 @@ import { Response } from './response.js';
 import { SessionLog } from './sessionLog.js';
 import { filteredTools } from './tools.js';
 import { packageJSON } from './package.js';
-import { defineTool  } from './tools/tool.js';
 
 import type { Tool } from './tools/tool.js';
 import type { BrowserContextFactory } from './browserContextFactory.js';
 import type * as mcpServer from './mcp/server.js';
 import type { ServerBackend } from './mcp/server.js';
 
-type NonEmptyArray<T> = [T, ...T[]];
-
-export type FactoryList = NonEmptyArray<BrowserContextFactory>;
-
 export class BrowserServerBackend implements ServerBackend {
   name = 'Playwright';
   version = packageJSON.version;
@@ -44,12 +38,10 @@ export class BrowserServerBackend implements ServerBackend {
   private _config: FullConfig;
   private _browserContextFactory: BrowserContextFactory;
 
-  constructor(config: FullConfig, factories: FactoryList) {
+  constructor(config: FullConfig, factory: BrowserContextFactory) {
     this._config = config;
-    this._browserContextFactory = factories[0];
+    this._browserContextFactory = factory;
     this._tools = filteredTools(config);
-    if (factories.length > 1)
-      this._tools.push(this._defineContextSwitchTool(factories));
   }
 
   async initialize(server: mcpServer.Server): Promise<void> {
@@ -77,8 +69,9 @@ export class BrowserServerBackend implements ServerBackend {
     return this._tools.map(tool => tool.schema);
   }
 
-  async callTool(schema: mcpServer.ToolSchema<any>, parsedArguments: any) {
+  async callTool(schema: mcpServer.ToolSchema<any>, rawArguments: any) {
     const context = this._context!;
+    const parsedArguments = schema.inputSchema.parse(rawArguments || {});
     const response = new Response(context, schema.name, parsedArguments);
     const tool = this._tools.find(tool => tool.schema.name === schema.name)!;
     context.setRunningTool(true);
@@ -97,46 +90,4 @@ export class BrowserServerBackend implements ServerBackend {
   serverClosed() {
     void this._context!.dispose().catch(logUnhandledError);
   }
-
-  private _defineContextSwitchTool(factories: FactoryList): Tool<any> {
-    const self = this;
-    return defineTool({
-      capability: 'core',
-
-      schema: {
-        name: 'browser_connect',
-        title: 'Connect to a browser context',
-        description: [
-          'Connect to a browser using one of the available methods:',
-          ...factories.map(factory => `- "${factory.name}": ${factory.description}`),
-        ].join('\n'),
-        inputSchema: z.object({
-          method: z.enum(factories.map(factory => factory.name) as [string, ...string[]]).default(factories[0].name).describe('The method to use to connect to the browser'),
-        }),
-        type: 'readOnly',
-      },
-
-      async handle(context, params, response) {
-        const factory = factories.find(factory => factory.name === params.method);
-        if (!factory) {
-          response.addError('Unknown connection method: ' + params.method);
-          return;
-        }
-        await self._setContextFactory(factory);
-        response.addResult('Successfully changed connection method.');
-      }
-    });
-  }
-
-  private async _setContextFactory(newFactory: BrowserContextFactory) {
-    if (this._context) {
-      const options = {
-        ...this._context.options,
-        browserContextFactory: newFactory,
-      };
-      await this._context.dispose();
-      this._context = new Context(options);
-    }
-    this._browserContextFactory = newFactory;
-  }
 }