fill

Type text into an input, text area or select an option from a <select> element.

SERVERChrome Devtools SOURCE@async23/chrome-devtools-mcp

Medium RISK CLASS

Category Write

Parameters 00 required

Recommended Rate-limitedsee the rule below

Registry record Grade F, identity unverified Pull the record →

This record as markdown: /tools/async23-chrome-devtools-mcp/fill.md

WHAT IT DOES

What fill does on Chrome Devtools

AI agents use fill to create or update resources in Chrome Devtools, usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Chrome Devtools environment.

RISK

Why fill is rated Medium

The tool modifies browser form input state reversibly. While it can change data in web applications, it operates at the UI interaction level and does not execute arbitrary code, delete data irreversibly, or move funds.

From the tool's definition Tool description states 'Type text into an input, text area or select an option from a <select> element.' This modifies form fields but does not execute arbitrary operations or delete data.

Attacks that exploit this kind of access

RECOMMENDED RULE

The rule that runs fill safely

PolicyLayer is an MCP gateway: it sits between your AI agents and Chrome Devtools, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For fill, this is the rule to start with:

fill Rate-limited

fill 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": {
    "fill": {
      "limits": [
        {
          "counter": "fill_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

LIMIT THIS TOOL → Instant setup, no code required.

The button opens the PolicyLayer dashboard: create your workspace, connect Chrome Devtools, apply this rule, and every fill call is checked against it from then on.

FAQ

Questions about fill

What does the fill tool do? +

Type text into an input, text area or select an option from a <select> element. It is categorised as a Write tool in the Chrome Devtools MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on fill? +

Register the Chrome Devtools MCP server in PolicyLayer and add a rule for fill: 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 fill? +

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

Can I rate-limit fill? +

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

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

fill is provided by the Chrome Devtools MCP server (@async23/chrome-devtools-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

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