2026/05/27 - Debug mabl tests from your AI coding agent

To help streamline your troubleshooting workflow, you can now use the mabl debugger in your AI coding agent to triage failures, reproduce them in a real Chrome window, and confirm a passing run before you open a PR. No more jumping between the run output, your local code, and a browser to verify the fix.

Included in the latest version of the mabl CLI, the new mabl agent debug command gives your agent two ways to handle failed runs:

• Investigate failures: retrieve the step trace, console output, network requests (HAR), DOM snapshot, and screenshot from any failed run. Your agent investigates the failure with the same evidence you would.
• Debug live: open a local Chrome session driven by the agent. The agent executes the test step-by-step, inspects the live page, applies your fix, and re-runs the failing step to confirm it passes.

By retrieving only relevant artifacts and confirming issues in real time, the mabl debugger keeps your sessions lean and minimizes unnecessary token consumption.

Try it out

Before you start, make sure you have the following installed:

• An AI coding agent that supports MCPs, such as Claude Code, Cursor, VSCode, GitHub Copilot, or any other client that reads an AGENTS.md file.
• The latest version of the mabl CLI

To use the mabl debugger, you'll need to be logged in to the mabl CLI:

mabl auth login

Install the mabl debugger

To install the mabl debugging skill into your agent, run the following command in the mabl CLI:

mabl agent install [client]

Replace [client] with the name of your agent, such as claude, cursor, vscode, copilot, or agents-md for other tools. For example, if you're installing the debugger in Claude Code, run this command:

mabl agent install claude

The install command adds three tools:

• mabl debug skill - gives your agent the ability to extract data from failing mabl tests to analyze and resolve issues
• mabl MCP - gives your agent access to your mabl workspace and tools for retrieving results, analyzing failures, and more
• chrome-for-mabl MCP - gives your agent the ability to observe a live debug session and interact with your browser

Investigate failures

Ask your agent for a recent mabl test failure and initiate the debugging process with a prompt:

"Can we debug this test run locally?"

The agent pulls the trace, reads the artifacts, and proposes a hypothesis.

Debug live

To dig deeper, ask your agent to reproduce the failure locally:

"Can we reproduce this locally?"

The agent initiates a local Chrome for Testing session to execute the test step-by-step. Once complete, it provides a summary and suggests specific resolutions, such as test updates or code fixes, so you can finalize the fix without leaving your agent session.

Learn more

Check out the docs for more details on optional install flags and a breakdown of the 4-step debug loop.