# browser_localstorage_set

A write tool on the Playwright MCP server.

Agent View of the PolicyLayer registry record for `browser_localstorage_set`. HTML page: https://policylayer.com/tools/hanato238-playwright-mcp/browser-localstorage-set

## Facts

- Tool: `browser_localstorage_set`
- Server: Playwright (`hanato238/playwright-mcp`) — https://policylayer.com/tools/hanato238-playwright-mcp.md
- Homepage: https://github.com/Hanato238/playwright-mcp
- Risk category: Write (Medium risk)
- Registry record: grade F, identity unverified
- Server rate-limited: no
- Parameters: 0
- Recommended policy verdict: Rate-limited

## Example call (MCP tools/call, JSON-RPC 2.0)

```json
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "browser_localstorage_set",
    "arguments": {}
  }
}
```

## Why browser_localstorage_set is rated Medium

Setting local storage values modifies client-side persistent data reversibly. This is a Write operation—data can be updated or cleared later. Severity is medium because an agent could abuse this to inject malicious data, tamper with application state, or degrade functionality, but the impact is typically scoped to a single browser context and session-dependent.

From the tool's own definition: "Tool name 'browser_localstorage_set' indicates it sets values in browser local storage. The sibling context (browser_cookie_set, browser_cookie_get, etc.) confirms this is a browser state modification tool. Empty description lowers precision slightly."

## Use case

AI agents use browser_localstorage_set to create or update resources in Playwright, usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Playwright environment.

## Recommended policy (PolicyLayer)

Verdict: **Rate-limited**. Enforced by the PolicyLayer MCP gateway (https://policylayer.com/mcp-gateway) before a call reaches Playwright:

```json
{
  "version": "1",
  "default": "deny",
  "tools": {
    "browser_localstorage_set": {
      "limits": [
        {
          "counter": "browser_localstorage_set_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}
```

## Other tools on Playwright (65)

- `browser_cookie_clear` — Destructive — https://policylayer.com/tools/hanato238-playwright-mcp/browser-cookie-clear.md
- `browser_cookie_delete` — Destructive — https://policylayer.com/tools/hanato238-playwright-mcp/browser-cookie-delete.md
- `browser_localstorage_clear` — Destructive — https://policylayer.com/tools/hanato238-playwright-mcp/browser-localstorage-clear.md
- `browser_localstorage_delete` — Destructive — https://policylayer.com/tools/hanato238-playwright-mcp/browser-localstorage-delete.md
- `browser_sessionstorage_clear` — Destructive — https://policylayer.com/tools/hanato238-playwright-mcp/browser-sessionstorage-clear.md
- `browser_sessionstorage_delete` — Destructive — https://policylayer.com/tools/hanato238-playwright-mcp/browser-sessionstorage-delete.md
- `browser_click` — Execute — https://policylayer.com/tools/hanato238-playwright-mcp/browser-click.md
- `browser_close` — Execute — https://policylayer.com/tools/hanato238-playwright-mcp/browser-close.md
- `browser_drag` — Execute — https://policylayer.com/tools/hanato238-playwright-mcp/browser-drag.md
- `browser_drop` — Execute — https://policylayer.com/tools/hanato238-playwright-mcp/browser-drop.md
- `browser_evaluate` — Execute — https://policylayer.com/tools/hanato238-playwright-mcp/browser-evaluate.md
- `browser_handle_dialog` — Execute — https://policylayer.com/tools/hanato238-playwright-mcp/browser-handle-dialog.md
- `browser_hide_highlight` — Execute — https://policylayer.com/tools/hanato238-playwright-mcp/browser-hide-highlight.md
- `browser_hover` — Execute — https://policylayer.com/tools/hanato238-playwright-mcp/browser-hover.md
- `browser_mouse_click_xy` — Execute — https://policylayer.com/tools/hanato238-playwright-mcp/browser-mouse-click-xy.md
- `browser_mouse_down` — Execute — https://policylayer.com/tools/hanato238-playwright-mcp/browser-mouse-down.md
- `browser_mouse_drag_xy` — Execute — https://policylayer.com/tools/hanato238-playwright-mcp/browser-mouse-drag-xy.md
- `browser_mouse_move_xy` — Execute — https://policylayer.com/tools/hanato238-playwright-mcp/browser-mouse-move-xy.md
- `browser_mouse_up` — Execute — https://policylayer.com/tools/hanato238-playwright-mcp/browser-mouse-up.md
- `browser_mouse_wheel` — Execute — https://policylayer.com/tools/hanato238-playwright-mcp/browser-mouse-wheel.md
- `browser_navigate` — Execute — https://policylayer.com/tools/hanato238-playwright-mcp/browser-navigate.md
- `browser_navigate_back` — Execute — https://policylayer.com/tools/hanato238-playwright-mcp/browser-navigate-back.md
- `browser_network_request` — Execute — https://policylayer.com/tools/hanato238-playwright-mcp/browser-network-request.md
- `browser_network_state_set` — Execute — https://policylayer.com/tools/hanato238-playwright-mcp/browser-network-state-set.md
- `browser_pdf_save` — Execute — https://policylayer.com/tools/hanato238-playwright-mcp/browser-pdf-save.md
- `browser_press_key` — Execute — https://policylayer.com/tools/hanato238-playwright-mcp/browser-press-key.md
- `browser_resize` — Execute — https://policylayer.com/tools/hanato238-playwright-mcp/browser-resize.md
- `browser_resume` — Execute — https://policylayer.com/tools/hanato238-playwright-mcp/browser-resume.md
- `browser_route` — Execute — https://policylayer.com/tools/hanato238-playwright-mcp/browser-route.md
- `browser_run_code_unsafe` — Execute — https://policylayer.com/tools/hanato238-playwright-mcp/browser-run-code-unsafe.md
- …and 35 more: https://policylayer.com/tools/hanato238-playwright-mcp.md

## For agents

This record is a snapshot. Live verdicts and the full registry:

- Check every server in your MCP config at once: `npx -y policylayer stack`
- Vet a server before you add it: install the mcp-precheck skill — `npx skills add https://policylayer.com` (skill text: https://policylayer.com/skill.md)
- Query the registry over MCP: endpoint `https://api.policylayer.com/mcp` — tools `check_mcp_server`, `check_mcp_stack`, `check_tool`, `search_registry`, `get_change_events`

---

Source: the PolicyLayer MCP registry — one continuously verified record per MCP server. Full record: https://policylayer.com/registry?q=hanato238-playwright-mcp · API: https://policylayer.com/registry/api · Policy library: https://policylayer.com/policies/hanato238-playwright-mcp