# safari_evaluate_js

Runs arbitrary JavaScript in the current Safari tab and returns its result. Requires 'Allow JavaScript from Apple Events' in Safari's Develop menu.

Agent View of the PolicyLayer registry record for `safari_evaluate_js`. HTML page: https://policylayer.com/tools/com-local-mcp-local-mcp/safari-evaluate-js

## Facts

- Tool: `safari_evaluate_js`
- Server: Local (`local-mcp`) — https://policylayer.com/tools/com-local-mcp-local-mcp.md
- Install: `npx -y local-mcp`
- Homepage: https://github.com/lanchuske/local-mcp
- Risk category: Execute (High risk)
- Registry record: grade F, identity unverified
- Server auth posture: open
- Server CORS policy: *
- Server rate-limited: no
- Parameters: 1 (1 required)
- Recommended policy verdict: Rate-limited

## Parameters

| Parameter | Type | Required | Description |
| --- | --- | --- | --- |
| `script` | string | yes |  |

Parameters from the server's own tool schema.

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

```json
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "safari_evaluate_js",
    "arguments": {
      "script": "<script>"
    }
  }
}
```

## Why safari_evaluate_js is rated High

This tool executes arbitrary JavaScript code in a live browser tab. An AI agent could use it to exfiltrate data, manipulate DOM, perform actions on behalf of the user, or interact with any web application currently open. Arbitrary code execution in a browser context is critical severity due to the unlimited blast radius across all open web sessions.

From the tool's own definition: "Runs arbitrary JavaScript in the current Safari tab"

Risk signals: Accepts freeform code/query input (script)

## Use case

AI agents invoke safari_evaluate_js to trigger actions in Local. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call: builds kicked off, notifications sent, workflows started.

## Recommended policy (PolicyLayer)

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

```json
{
  "version": "1",
  "default": "deny",
  "tools": {
    "safari_evaluate_js": {
      "limits": [
        {
          "counter": "safari_evaluate_js_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}
```

## Other tools on Local (233)

- `delete_calendar_event` — Destructive — https://policylayer.com/tools/com-local-mcp-local-mcp/delete-calendar-event.md
- `delete_reminder` — Destructive — https://policylayer.com/tools/com-local-mcp-local-mcp/delete-reminder.md
- `delete_reminder_list` — Destructive — https://policylayer.com/tools/com-local-mcp-local-mcp/delete-reminder-list.md
- `m365_delete_event` — Destructive — https://policylayer.com/tools/com-local-mcp-local-mcp/m365-delete-event.md
- `onedrive_delete_file` — Destructive — https://policylayer.com/tools/com-local-mcp-local-mcp/onedrive-delete-file.md
- `recipe_delete` — Destructive — https://policylayer.com/tools/com-local-mcp-local-mcp/recipe-delete.md
- `chrome_click` — Execute — https://policylayer.com/tools/com-local-mcp-local-mcp/chrome-click.md
- `chrome_evaluate_js` — Execute — https://policylayer.com/tools/com-local-mcp-local-mcp/chrome-evaluate-js.md
- `chrome_fill_form` — Execute — https://policylayer.com/tools/com-local-mcp-local-mcp/chrome-fill-form.md
- `chrome_go_back` — Execute — https://policylayer.com/tools/com-local-mcp-local-mcp/chrome-go-back.md
- `chrome_navigate` — Execute — https://policylayer.com/tools/com-local-mcp-local-mcp/chrome-navigate.md
- `chrome_type` — Execute — https://policylayer.com/tools/com-local-mcp-local-mcp/chrome-type.md
- `chrome_wait_for` — Execute — https://policylayer.com/tools/com-local-mcp-local-mcp/chrome-wait-for.md
- `nordvpn_diagnose` — Execute — https://policylayer.com/tools/com-local-mcp-local-mcp/nordvpn-diagnose.md
- `notion_open_page` — Execute — https://policylayer.com/tools/com-local-mcp-local-mcp/notion-open-page.md
- `recipe_run` — Execute — https://policylayer.com/tools/com-local-mcp-local-mcp/recipe-run.md
- `run_diagnostics` — Execute — https://policylayer.com/tools/com-local-mcp-local-mcp/run-diagnostics.md
- `run_terminal_command` — Execute — https://policylayer.com/tools/com-local-mcp-local-mcp/run-terminal-command.md
- `safari_click` — Execute — https://policylayer.com/tools/com-local-mcp-local-mcp/safari-click.md
- `safari_fill_form` — Execute — https://policylayer.com/tools/com-local-mcp-local-mcp/safari-fill-form.md
- `safari_go_back` — Execute — https://policylayer.com/tools/com-local-mcp-local-mcp/safari-go-back.md
- `safari_navigate` — Execute — https://policylayer.com/tools/com-local-mcp-local-mcp/safari-navigate.md
- `safari_query_selector_all` — Execute — https://policylayer.com/tools/com-local-mcp-local-mcp/safari-query-selector-all.md
- `safari_type` — Execute — https://policylayer.com/tools/com-local-mcp-local-mcp/safari-type.md
- `safari_wait_for` — Execute — https://policylayer.com/tools/com-local-mcp-local-mcp/safari-wait-for.md
- `screen_record_start` — Execute — https://policylayer.com/tools/com-local-mcp-local-mcp/screen-record-start.md
- `screen_record_stop` — Execute — https://policylayer.com/tools/com-local-mcp-local-mcp/screen-record-stop.md
- `setup_install` — Execute — https://policylayer.com/tools/com-local-mcp-local-mcp/setup-install.md
- `ui_click` — Execute — https://policylayer.com/tools/com-local-mcp-local-mcp/ui-click.md
- `ui_keystroke` — Execute — https://policylayer.com/tools/com-local-mcp-local-mcp/ui-keystroke.md
- …and 203 more: https://policylayer.com/tools/com-local-mcp-local-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=com-local-mcp-local-mcp · API: https://policylayer.com/registry/api · Policy library: https://policylayer.com/policies/com-local-mcp-local-mcp