Show HN: Cursor for Userscripts

Why It Matters

By bypassing CSP restrictions and integrating directly with the userscript ecosystem, the tool makes AI‑assisted web automation instantly deployable, reshaping front‑end development workflows. It signals a broader shift toward on‑the‑fly code generation inside browsers, accelerating prototyping and reducing manual scripting effort.

Key Takeaways

• Claude-powered virtual filesystem for DOM editing
• Scripts persist via Chrome userScripts API, bypassing CSP
• Plan mode separates analysis from execution for safety
• Chrome syncs scripts bidirectionally with local filesystem
• Dynamic route patterns expose parameters via __routeParams

Pulse Analysis

AI‑driven agents have long promised to automate repetitive web tasks, yet developers have struggled with content‑security‑policy (CSP) walls and fragmented tooling. Traditional userscript managers like Tampermonkey require manual script authoring and cannot natively interact with an AI model’s internal state. Browser Code bridges that gap by exposing the entire DOM as a virtual file system, allowing Claude to read, edit, and version‑track page elements just as a developer would in a local IDE. This architecture eliminates the need for copy‑paste workflows and gives the AI a deterministic view of the page, dramatically improving reliability.

The extension’s core consists of a background service worker that mediates Claude’s API calls, a content script that implements the virtual filesystem, and a React sidebar for interactive chat and file browsing. Files such as page.html, console.log, and custom scripts live under domain‑based paths, each carrying a version number to prevent stale edits. A two‑step Plan/Execute model forces the agent to propose changes in a read‑only plan mode before any DOM mutation occurs, while dynamic route patterns automatically inject URL parameters into window.__routeParams. These safeguards make on‑the‑fly script generation safe for production sites, even those with strict CSP or Trusted Types policies.

For developers, Browser Code turns the browser into a live coding environment where AI suggestions can be reviewed, edited in VS Code, and synced back instantly via Chrome’s File System Access API. This reduces the time from idea to functional script from hours to minutes and opens the door for collaborative AI‑assisted debugging. As more extensions adopt similar AI‑first architectures, the market may see a surge in intelligent tooling that blurs the line between static userscripts and adaptive, context‑aware web agents, reshaping how front‑end teams build and maintain site‑specific functionality.