diff --git a/src/context.ts b/src/context.ts
index 76f461c..49472cc 100644
--- a/src/context.ts
+++ b/src/context.ts
@@ -125,7 +125,7 @@ export class Context {
 
   async run(tool: Tool, params: Record<string, unknown> | undefined) {
     // Tab management is done outside of the action() call.
-    const toolResult = await tool.handle(this, tool.schema.inputSchema.parse(params));
+    const toolResult = await tool.handle(this, tool.schema.inputSchema.parse(params || {}));
     const { code, action, waitForNetwork, captureSnapshot, resultOverride } = toolResult;
     const racingAction = action ? () => this._raceAgainstModalDialogs(action) : undefined;
 
diff --git a/tests/cdp.spec.ts b/tests/cdp.spec.ts
index 7f437e4..4d2ff65 100644
--- a/tests/cdp.spec.ts
+++ b/tests/cdp.spec.ts
@@ -37,7 +37,6 @@ test('cdp server reuse tab', async ({ cdpEndpoint, startClient }) => {
 
   expect(await client.callTool({
     name: 'browser_snapshot',
-    arguments: {},
   })).toHaveTextContent(`
 - Ran Playwright code:
 \`\`\`js
diff --git a/tests/console.spec.ts b/tests/console.spec.ts
index 781db5a..8a9f60a 100644
--- a/tests/console.spec.ts
+++ b/tests/console.spec.ts
@@ -36,7 +36,6 @@ test('browser_console_messages', async ({ client, server }) => {
 
   const resource = await client.callTool({
     name: 'browser_console_messages',
-    arguments: {},
   });
   expect(resource).toHaveTextContent([
     '[LOG] Hello, world!',
diff --git a/tests/core.spec.ts b/tests/core.spec.ts
index 9d4f058..003ea98 100644
--- a/tests/core.spec.ts
+++ b/tests/core.spec.ts
@@ -175,7 +175,6 @@ test('browser_type', async ({ client, server }) => {
   });
   expect(await client.callTool({
     name: 'browser_console_messages',
-    arguments: {},
   })).toHaveTextContent('[LOG] Key pressed: Enter , Text: Hi!');
 });
 
@@ -202,7 +201,6 @@ test('browser_type (slowly)', async ({ client, server }) => {
   });
   expect(await client.callTool({
     name: 'browser_console_messages',
-    arguments: {},
   })).toHaveTextContent([
     '[LOG] Key pressed: H Text: ',
     '[LOG] Key pressed: i Text: H',
@@ -237,5 +235,5 @@ test('browser_resize', async ({ client, server }) => {
 // Resize browser window to 390x780
 await page.setViewportSize({ width: 390, height: 780 });
 \`\`\``);
-  await expect.poll(() => client.callTool({ name: 'browser_snapshot', arguments: {} })).toContainTextContent('Window size: 390x780');
+  await expect.poll(() => client.callTool({ name: 'browser_snapshot' })).toContainTextContent('Window size: 390x780');
 });
diff --git a/tests/files.spec.ts b/tests/files.spec.ts
index cce1b9a..8280bb0 100644
--- a/tests/files.spec.ts
+++ b/tests/files.spec.ts
@@ -121,7 +121,7 @@ test('clicking on download link emits download', async ({ startClient, localOutp
       ref: 'e2',
     },
   });
-  await expect.poll(() => client.callTool({ name: 'browser_snapshot', arguments: {} })).toContainTextContent(`
+  await expect.poll(() => client.callTool({ name: 'browser_snapshot' })).toContainTextContent(`
 ### Downloads
 - Downloaded file test.txt to ${path.join(outputDir, 'test.txt')}`);
 });
diff --git a/tests/install.spec.ts b/tests/install.spec.ts
index 34ce5bb..66a11d5 100644
--- a/tests/install.spec.ts
+++ b/tests/install.spec.ts
@@ -20,6 +20,5 @@ test('browser_install', async ({ client, mcpBrowser }) => {
   test.skip(mcpBrowser !== 'chromium', 'Test only chromium');
   expect(await client.callTool({
     name: 'browser_install',
-    arguments: {},
   })).toContainTextContent(`No open pages available.`);
 });
diff --git a/tests/launch.spec.ts b/tests/launch.spec.ts
index 9bfba46..d263abd 100644
--- a/tests/launch.spec.ts
+++ b/tests/launch.spec.ts
@@ -24,7 +24,6 @@ test('test reopen browser', async ({ client, server }) => {
 
   expect(await client.callTool({
     name: 'browser_close',
-    arguments: {},
   })).toContainTextContent('No open pages available');
 
   expect(await client.callTool({
diff --git a/tests/network.spec.ts b/tests/network.spec.ts
index 47b335a..56e71c0 100644
--- a/tests/network.spec.ts
+++ b/tests/network.spec.ts
@@ -40,7 +40,6 @@ test('browser_network_requests', async ({ client, server }) => {
 
   await expect.poll(() => client.callTool({
     name: 'browser_network_requests',
-    arguments: {},
   })).toHaveTextContent(`[GET] ${`${server.PREFIX}`} => [200] OK
 [GET] ${`${server.PREFIX}json`} => [200] OK`);
 });
diff --git a/tests/pdf.spec.ts b/tests/pdf.spec.ts
index 120a6ca..1e870e6 100644
--- a/tests/pdf.spec.ts
+++ b/tests/pdf.spec.ts
@@ -40,7 +40,6 @@ test('save as pdf', async ({ client, mcpBrowser, server }) => {
 
   const response = await client.callTool({
     name: 'browser_pdf_save',
-    arguments: {},
   });
   expect(response).toHaveTextContent(/Save page as.*page-[^:]+.pdf/);
 });
diff --git a/tests/screenshot.spec.ts b/tests/screenshot.spec.ts
index 1c80dda..1909a8b 100644
--- a/tests/screenshot.spec.ts
+++ b/tests/screenshot.spec.ts
@@ -26,7 +26,6 @@ test('browser_take_screenshot (viewport)', async ({ client, server }) => {
 
   expect(await client.callTool({
     name: 'browser_take_screenshot',
-    arguments: {},
   })).toEqual({
     content: [
       {
@@ -81,7 +80,6 @@ test('--output-dir should work', async ({ startClient, localOutputPath, server }
 
   await client.callTool({
     name: 'browser_take_screenshot',
-    arguments: {},
   });
 
   expect(fs.existsSync(outputDir)).toBeTruthy();
@@ -180,12 +178,10 @@ test('browser_take_screenshot (noImageResponses)', async ({ startClient, server
 
   await client.callTool({
     name: 'browser_take_screenshot',
-    arguments: {},
   });
 
   expect(await client.callTool({
     name: 'browser_take_screenshot',
-    arguments: {},
   })).toEqual({
     content: [
       {
@@ -206,12 +202,10 @@ test('browser_take_screenshot (cursor)', async ({ startClient, server }) => {
 
   await client.callTool({
     name: 'browser_take_screenshot',
-    arguments: {},
   });
 
   expect(await client.callTool({
     name: 'browser_take_screenshot',
-    arguments: {},
   })).toEqual({
     content: [
       {
diff --git a/tests/tabs.spec.ts b/tests/tabs.spec.ts
index 99652d9..1972782 100644
--- a/tests/tabs.spec.ts
+++ b/tests/tabs.spec.ts
@@ -32,7 +32,6 @@ async function createTab(client: Client, title: string, body: string) {
 test('list initial tabs', async ({ client }) => {
   expect(await client.callTool({
     name: 'browser_tab_list',
-    arguments: {},
   })).toHaveTextContent(`### Open tabs
 - 1: (current) [] (about:blank)`);
 });
@@ -41,7 +40,6 @@ test('list first tab', async ({ client }) => {
   await createTab(client, 'Tab one', 'Body one');
   expect(await client.callTool({
     name: 'browser_tab_list',
-    arguments: {},
   })).toHaveTextContent(`### Open tabs
 - 1: [] (about:blank)
 - 2: (current) [Tab one] (data:text/html,<title>Tab one</title><body>Body one</body>)`);