Tester Agent

Tester Agent is an open-source MCP server for exploratory web QA. A model in Codex or Antigravity can inspect a live Chromium page, see its viewport, click and fill controls, verify outcomes, and export findings for developers. Each project supplies a URL and its test criteria; there is no project-specific Playwright script to write.

• Functional QA: check single scenarios or complete workflows with ordered checkpoints and assertions.

• Visual QA: compare desktop and mobile, inspect layout and accessibility signals, and attach screenshot evidence to findings.

• Defensive QA: observe transport, headers, cookie flags and password forms. Verify expected sign-in, sign-out and role behavior through the normal UI with QA accounts. This is not a penetration testing tool.

Install from GitHub

Requires Node.js 24+, npm and the Chromium build installed by Playwright. The installer targets macOS and Linux; Codex setup uses the codex CLI. If that CLI is unavailable, register the MCP manually in Codex Desktop.

git clone https://github.com/datb2404981/tester-agent-mcp.git
cd tester-agent-mcp
npm ci
npx playwright install chromium
node scripts/install.mjs --dry-run --only=codex
node scripts/install.mjs --only=codex

For Antigravity, use node scripts/install.mjs --only=antigravity. Omit --only to install both. Restart Codex Desktop or reload Antigravity's MCP configuration and open a new chat. If migrating a recognized older Tester Agent install, preview the change with --dry-run --replace-managed first. The installer also installs six QA skills; the server exposes those same guides as MCP prompts and resources.

For manual setup, add a stdio server called tester-agent. Set the command to the absolute path to Node (find it with node -p 'process.execPath'), and set its sole argument to the absolute path to src/server.mjs in the clone. The skills are also available in the repository's skills directory.

Related MCP server: QualityMax QA MCP

Try it in a new chat

With your local test app running, replace the URL below with its address:

Dùng Tester Agent kiểm tra http://localhost:3000. Bắt đầu ở chế độ chỉ đọc. Nhìn giao diện trên desktop và mobile, tìm tràn ngang và lỗi trợ năng. Ghi rõ các kiểm tra đã làm và xuất báo cáo Markdown cho dev.

For a workflow that changes data, provide the expected outcome, authorized QA environment and disposable test data. The model drives the browser tool by tool. The MCP server has no separate model provider or API key; visual judgment requires an MCP client and model that can consume image results. This version runs browser QA and read-only scans through the connected model, without an Explorbot script runner.

Register remote targets with environment=qa and allowRemote=true. Use allowWrites=true only for authorized test data. Register necessary API or asset origins in allowedOrigins. Page navigation is limited to the registered site and base path; assets and APIs can use registered origins. The server stops at HTTP redirects, so flows that require a redirect (such as some sign-in and SSO flows) are blocked. Use the final URL for read-only checks where applicable. Read-only mode limits requests and interaction, but a GET can still have side effects. Use isolated QA data and review evidence before sharing it. Input masking and text redaction do not guarantee that a page contains no sensitive data.

Reports

tester_browser_finish and tester_test_web return the original report and a bug report in JSON and Markdown. The default output directory is ~/.tester-agent/projects/<project>/output/reports. Set TESTER_STATE_DIR to use a different root. List and read the reports with tester_project_artifacts and tester_project_read_artifact.

Each finding carries a severity, expected and actual behavior, reproduction steps when recorded, evidence, and verification status. PASS applies only to the completed checks. FAIL records a failed check or observed error; BLOCKED means execution or evidence was incomplete. REVIEW_REQUIRED marks signals or findings that need judgment. OBSERVED describes a passive audit, without a claim of security or WCAG compliance. A scan does not verify business workflows.

Update or remove

To update, run git pull --ff-only, npm ci and npx playwright install chromium inside the clone. Reload your MCP client. To remove the server, run codex mcp remove tester-agent or remove its entry from Antigravity's MCP settings. Installed skills and report data can be removed separately.

Run npm test after installing Chromium. The suite runs against a disposable local website and does not require model credentials.

MIT license