fix: filter base64 image from screenshot result (#105)

Author: Burry

src/_internal/browser-eval-manager.ts

@@ -63,7 +63,7 @@ export async function startBrowserEvalMCP(options?: {
   console.error("[Browser Eval Manager] Starting playwright-mcp server with verbose logging...")
 
   // Build args for playwright-mcp
-  const args: string[] = ["@playwright/mcp@latest"]
+  const args: string[] = ["@playwright/mcp@latest", "--image-responses", "omit"]
 
   if (options?.browser) {
     args.push("--browser", options.browser)

test/unit/browser-eval-screenshot.test.ts

@@ -0,0 +1,73 @@
+import { describe, it, expect, vi, beforeEach, afterEach } from "vitest"
+
+// Mock the mcp-client module before importing browser-eval-manager
+vi.mock("../../src/_internal/mcp-client.js", () => ({
+  connectToMCPServer: vi.fn(),
+  callServerTool: vi.fn(),
+  listServerTools: vi.fn(),
+}))
+
+// Mock the exec function to skip installation check
+vi.mock("child_process", () => ({
+  exec: vi.fn((cmd, callback) => {
+    callback(null, { stdout: "@playwright/mcp@1.0.0" })
+  }),
+}))
+
+import { connectToMCPServer, callServerTool } from "../../src/_internal/mcp-client.js"
+import {
+  startBrowserEvalMCP,
+  stopBrowserEvalMCP,
+} from "../../src/_internal/browser-eval-manager.js"
+import { handler } from "../../src/tools/browser-eval.js"
+
+describe("browser-eval playwright-mcp screenshot tool", () => {
+  beforeEach(() => {
+    vi.clearAllMocks()
+    vi.mocked(connectToMCPServer).mockResolvedValue({
+      client: { close: vi.fn() },
+      transport: { close: vi.fn() },
+    } as never)
+  })
+
+  afterEach(async () => {
+    await stopBrowserEvalMCP()
+  })
+
+  it("should pass --image-responses omit flag to playwright-mcp", async () => {
+    await startBrowserEvalMCP()
+
+    expect(connectToMCPServer).toHaveBeenCalledWith(
+      "npx",
+      expect.arrayContaining(["--image-responses", "omit"]),
+      expect.any(Object)
+    )
+  })
+
+  it("should return screenshot file path without base64 image data", async () => {
+    await startBrowserEvalMCP()
+
+    const screenshotPath = "/var/folders/tmp/screenshot-1234.png"
+    vi.mocked(callServerTool).mockResolvedValue({
+      content: [{ type: "text", text: `Screenshot saved to ${screenshotPath}` }],
+    })
+
+    const result = await handler({ action: "screenshot" })
+    const parsed = JSON.parse(result)
+
+    expect(parsed.success).toBe(true)
+    expect(parsed.action).toBe("screenshot")
+
+    // Verify response contains file path
+    const textContent = parsed.result.content.find(
+      (block: { type: string }) => block.type === "text"
+    )
+    expect(textContent.text).toContain(screenshotPath)
+
+    // Verify no base64 image data in response
+    const imageContent = parsed.result.content.find(
+      (block: { type: string }) => block.type === "image"
+    )
+    expect(imageContent).toBeUndefined()
+  })
+})