trigger_extension_action

THE RISK

High Risk

Why trigger_extension_action needs a policy

This tool causes the browser to execute an extension's default action, which is an irreversible operation dependent on what the extension does. While not directly destructive or financial in isolation, it represents code execution whose effects cannot be predicted without knowing the extension.

From the tool's definition Tool triggers external operations via extension IDs, whose effects depend on arguments and extension behavior. Sibling tools include 'execute_3p_developer_tool' and 'evaluate_script', situating this in the execution category.

Documented attack patterns abuse exactly the kind of access trigger_extension_action gives an agent:

POLICY

How to control trigger_extension_action

PolicyLayer is an MCP gateway — it sits between your AI agents and Chrome DevTools, and nothing reaches the server without passing your rules. This is the rule we recommend for trigger_extension_action:

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "trigger_extension_action": {
      "limits": [
        {
          "counter": "trigger_extension_action_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

trigger_extension_action stays usable, but rate-capped — a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.

Create a free account and register Chrome DevTools — nothing to install.
Add this policy — paste it, or build it visually.
Point your MCP client (Claude, Cursor, anything) at your gateway URL.

RATE-LIMIT THIS TOOL →

Free to start. No card required.

EXPLORE

Related tools and policies

More Chrome DevTools tools

Destructive uninstall_extension Uninstalls a Chrome extension by its ID. Destructive close_heapsnapshot Closes a previously loaded memory heapsnapshot, freeing its memory. Destructive close_page Closes the page by its index. The last open page cannot be closed. Execute emulate Emulates various features on the selected page. Execute execute_3p_developer_tool Executes a tool exposed by the page. Execute execute_webmcp_tool Executes a WebMCP tool exposed by the page. Execute lighthouse_audit Get Lighthouse score and reports for accessibility, SEO, best practices, and agentic brows Execute navigate Loads a URL

All 50 Chrome DevTools tools →

Execute tools on other servers

Android Forensics ADB MCP Server adb_shell_command EMBA-MCP run_emba_scan Frida Game Hacking MCP remove_breakpoint Procmon request_elevation

Go deeper

Govern code and CI agents → Branch allowlists, approval on merges, and rate caps on the build and pipeline tools agents trigger.
High-risk tools in Chrome DevTools → Every high-risk tool this server exposes, in one view.
All high-risk MCP tools → Every high-risk tool across the catalogue, and the policy pattern that contains them.
The MCP Attack Database → Documented attack patterns against MCP deployments — and the policies that stop them.
Agent sandbox → Bounding what an agent can execute and where the boundary should sit.
Least privilege for MCP → Granting agents the minimum tool surface the task needs.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →
PolicyLayer vs alternatives → How deterministic, per-call MCP policy compares with gateways, identity layers, and authorisation platforms.

FAQ

Questions about trigger_extension_action

What does the trigger_extension_action tool do? +

Triggers the default action of an extension by its ID. It is categorised as a Execute tool in the Chrome DevTools MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on trigger_extension_action? +

Register the Chrome DevTools MCP server in PolicyLayer and add a rule for trigger_extension_action: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches Chrome DevTools. Nothing to install.

What risk level is trigger_extension_action? +

trigger_extension_action is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.

Can I rate-limit trigger_extension_action? +

Yes. Add a rate_limit block to the trigger_extension_action rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.

How do I block trigger_extension_action completely? +

Set action: deny in the PolicyLayer policy for trigger_extension_action. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.

What MCP server provides trigger_extension_action? +

trigger_extension_action is provided by the Chrome DevTools MCP server (ChromeDevTools/chrome-devtools-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every Chrome DevTools tool call.

Start from Chrome DevTools, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.

CHECK YOUR STACK →