# execute_javascript

Execute JavaScript code in the browser context. Args: code: JavaScript code to execute Returns: Result of the JavaScript execution

Agent View of the PolicyLayer registry record for `execute_javascript`. HTML page: https://policylayer.com/tools/benjaminr-chrome-devtools-mcp/execute-javascript

## Facts

- Tool: `execute_javascript`
- Server: Chrome Devtools (`benjaminr/chrome-devtools-mcp`) — https://policylayer.com/tools/benjaminr-chrome-devtools-mcp.md
- Homepage: https://github.com/benjaminr/chrome-devtools-mcp
- Risk category: Execute (High 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": "execute_javascript",
    "arguments": {}
  }
}
```

## Why execute_javascript is rated High

This tool directly executes arbitrary code (JavaScript) in a live browser environment, which is the definition of the Execute category. The blast radius is high because an AI agent could use this to steal credentials, modify page content, exfiltrate data, perform phishing attacks, or interact with web applications in harmful ways.

From the tool's own definition: "Tool name is 'execute_javascript' and description states it 'Execute[s] JavaScript code in the browser context.' The argument 'code' accepts arbitrary JavaScript to be executed."

## Use case

AI agents invoke execute_javascript to trigger actions in Chrome Devtools. 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 Chrome Devtools:

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

## Other tools on Chrome Devtools (46)

- `clear_all_cookies` — Destructive — https://policylayer.com/tools/benjaminr-chrome-devtools-mcp/clear-all-cookies.md
- `clear_storage_for_origin` — Destructive — https://policylayer.com/tools/benjaminr-chrome-devtools-mcp/clear-storage-for-origin.md
- `clear_console` — Execute — https://policylayer.com/tools/benjaminr-chrome-devtools-mcp/clear-console.md
- `connect_to_browser` — Execute — https://policylayer.com/tools/benjaminr-chrome-devtools-mcp/connect-to-browser.md
- `evaluate_in_all_frames` — Execute — https://policylayer.com/tools/benjaminr-chrome-devtools-mcp/evaluate-in-all-frames.md
- `focus_element` — Execute — https://policylayer.com/tools/benjaminr-chrome-devtools-mcp/focus-element.md
- `inspect_console_object` — Execute — https://policylayer.com/tools/benjaminr-chrome-devtools-mcp/inspect-console-object.md
- `navigate_to_url` — Execute — https://policylayer.com/tools/benjaminr-chrome-devtools-mcp/navigate-to-url.md
- `override_storage_quota` — Execute — https://policylayer.com/tools/benjaminr-chrome-devtools-mcp/override-storage-quota.md
- `start_chrome` — Execute — https://policylayer.com/tools/benjaminr-chrome-devtools-mcp/start-chrome.md
- `start_chrome_and_connect` — Execute — https://policylayer.com/tools/benjaminr-chrome-devtools-mcp/start-chrome-and-connect.md
- `start_css_coverage_tracking` — Execute — https://policylayer.com/tools/benjaminr-chrome-devtools-mcp/start-css-coverage-tracking.md
- `track_indexeddb` — Execute — https://policylayer.com/tools/benjaminr-chrome-devtools-mcp/track-indexeddb.md
- `disconnect_from_browser` — Other — https://policylayer.com/tools/benjaminr-chrome-devtools-mcp/disconnect-from-browser.md
- `collect_css_class_names` — Read — https://policylayer.com/tools/benjaminr-chrome-devtools-mcp/collect-css-class-names.md
- `describe_element` — Read — https://policylayer.com/tools/benjaminr-chrome-devtools-mcp/describe-element.md
- `get_all_cookies` — Read — https://policylayer.com/tools/benjaminr-chrome-devtools-mcp/get-all-cookies.md
- `get_background_colors` — Read — https://policylayer.com/tools/benjaminr-chrome-devtools-mcp/get-background-colors.md
- `get_computed_styles` — Read — https://policylayer.com/tools/benjaminr-chrome-devtools-mcp/get-computed-styles.md
- `get_connection_status` — Read — https://policylayer.com/tools/benjaminr-chrome-devtools-mcp/get-connection-status.md
- `get_console_error_summary` — Read — https://policylayer.com/tools/benjaminr-chrome-devtools-mcp/get-console-error-summary.md
- `get_console_logs` — Read — https://policylayer.com/tools/benjaminr-chrome-devtools-mcp/get-console-logs.md
- `get_cookies` — Read — https://policylayer.com/tools/benjaminr-chrome-devtools-mcp/get-cookies.md
- `get_document` — Read — https://policylayer.com/tools/benjaminr-chrome-devtools-mcp/get-document.md
- `get_element_at_position` — Read — https://policylayer.com/tools/benjaminr-chrome-devtools-mcp/get-element-at-position.md
- `get_element_attributes` — Read — https://policylayer.com/tools/benjaminr-chrome-devtools-mcp/get-element-attributes.md
- `get_element_box_model` — Read — https://policylayer.com/tools/benjaminr-chrome-devtools-mcp/get-element-box-model.md
- `get_element_outer_html` — Read — https://policylayer.com/tools/benjaminr-chrome-devtools-mcp/get-element-outer-html.md
- `get_inline_styles` — Read — https://policylayer.com/tools/benjaminr-chrome-devtools-mcp/get-inline-styles.md
- `get_matched_styles` — Read — https://policylayer.com/tools/benjaminr-chrome-devtools-mcp/get-matched-styles.md
- …and 16 more: https://policylayer.com/tools/benjaminr-chrome-devtools-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=benjaminr-chrome-devtools-mcp · API: https://policylayer.com/registry/api · Policy library: https://policylayer.com/policies/benjaminr-chrome-devtools-mcp