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 use chrome_fill_or_select to create or update resources in Chrome MCP Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Chrome MCP Server environment.

WHY IT NEEDS A POLICY

Why chrome_fill_or_select needs a policy

This tool modifies form state by filling input fields and selecting dropdown/radio options. These changes are reversible (user can edit or clear forms), making it Write rather than Execute or Destructive. Severity is medium because form submission could trigger unintended actions if combined with automation, but the tool itself only populates forms without executing them.

From the tool's definition Tool name 'chrome_fill_or_select' and description 'Fill forms and select options' indicate creation or modification of form data in web pages.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

chrome_fill_or_select Rate-limited

chrome_fill_or_select stays usable, but capped — an agent stuck in a loop can't make hundreds of changes 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": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

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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 Write tool in the Chrome MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

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 Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.

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 (marie6789040106650/mcp-chrome-bk). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.