Agent tools for frontend work

A new crop of developer tools is giving artificial intelligence agents direct access to running web apps, not just the source code behind them. Callstack, Codejet, and Frontman each showed products that let agents inspect or change frontend software through the app itself. (github.com) (docs.codejet.ai) (github.com) Frontend software is the part users see in a browser: buttons, forms, menus, and layouts. In modern React apps, that interface is built from nested components that hold state, pass data through props, and re-render as users interact. (callstack.com) Callstack’s Agent React DevTools is an experimental project published on GitHub about two months ago. Its README says it lets an agent inspect the React component tree, read props and state, and profile rendering performance from the command line. (github.com 1) (github.com 2) The project’s release notes show it can export profiling sessions, compare before-and-after performance traces, and flag components with errors or warnings. Those are the same kinds of internals human developers use to debug slow or broken React interfaces. (github.com) Codejet is aiming at an earlier step in the workflow: turning interface designs into working code. Its documentation says users can install a Figma plugin, select a design, and convert it into HyperText Markup Language, Cascading Style Sheets, or JavaScript, then edit the result in a visual editor. (docs.codejet.ai 1) (docs.codejet.ai 2) Codejet’s docs also tie that flow to its Jet user interface design system, a library of more than 100 components, sections, and templates. In practice, that means the tool works best when the design already follows Codejet’s own building blocks rather than an arbitrary mockup. (docs.codejet.ai 1) (docs.codejet.ai 2) Frontman moves the agent into the browser itself. The open-source project says it hooks into a development server as middleware, sees the live Document Object Model, component tree, Cascading Style Sheets, routes, and server logs, and then edits the underlying source files with hot reload after a user describes a change in plain English. (github.com) That shift changes what an agent can verify on its own. Microsoft’s Visual Studio Code documentation describes browser agent tools as a closed loop in which an agent builds a web app, opens it in a browser, checks the page and console for problems, and then fixes them without waiting for a human to copy error messages back into a chat box. (code.visualstudio.com) The common thread is visibility. Instead of guessing from static files, these tools expose the live structure of an app — what rendered, what state changed, what route loaded, and what slowed down — so an agent can work with the same signals a frontend engineer already uses. (github.com) (github.com) That does not mean the tools solve the same problem. Callstack is focused on debugging React internals, Codejet on design-to-code generation inside Figma, and Frontman on editing a running project from the browser without opening a command-line interface. (github.com) (docs.codejet.ai) (github.com) Together, they show where frontend automation is moving in 2026: away from code autocomplete alone and toward agents that can inspect a live interface, understand how it is wired, and change the app with feedback from the browser. (github.com) (github.com)