chrome_fill_or_select · Chrome MCP Server MCP: Risk & Policy

WHAT IT DOES

What chrome_fill_or_select does on Chrome MCP Server

AI agents invoke chrome_fill_or_select to trigger actions in Chrome MCP Server. 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.

WHY IT NEEDS A POLICY

Why chrome_fill_or_select needs a policy

Form filling is an active browser manipulation action that can trigger side effects such as submitting credentials, personal data, or initiating workflows on external sites. It goes beyond reading or simple writing since it interacts with live browser sessions and can cause cascading actions depending on form content.

From the tool's definition Fill forms and select options — directly manipulates browser form elements, triggering input events and potentially submitting data to external services

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

chrome_fill_or_select Rate-limited

chrome_fill_or_select 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.

View as policy code

policy.json

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

RATE-LIMIT THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches Chrome MCP Server, so you can run agents against it safely.

FAQ

Questions about chrome_fill_or_select

What does the chrome_fill_or_select tool do? +

Fill forms and select options. It is categorised as a Execute tool in the Chrome MCP Server MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on chrome_fill_or_select? +

Register the Chrome MCP Server MCP server in PolicyLayer and add a rule for chrome_fill_or_select: 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 MCP Server. Nothing to install.

What risk level is chrome_fill_or_select? +

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

Can I rate-limit chrome_fill_or_select? +

Yes. Add a rate_limit block to the chrome_fill_or_select 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 chrome_fill_or_select completely? +

Set action: deny in the PolicyLayer policy for chrome_fill_or_select. 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 chrome_fill_or_select? +

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