Playwright MCP

browser_fill_form

Destructive

Fill multiple form fields in a web page at once by passing an array of targets and values, automating textboxes, checkboxes, radios, comboboxes, and sliders.

Instructions

Fill multiple form fields

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "fields": "<fields>"
    },
    "name": "browser_fill_form"
  }
}

Input Schema

Name	Required	Description	Default
`fields`	Yes	Fields to fill in

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.0.77Oct 19, 2026

TDQS

B3.2/5.0

Behavior3/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

The annotations already declare readOnlyHint=false and destructiveHint=true, so the write and potentially destructive nature is covered. The description adds the 'multiple form fields' detail but does not disclose additional behavior such as overwriting values or submitting the form.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single clear sentence with no redundant words or boilerplate. It is appropriately short and easy to parse, though it sacrifices deeper context for brevity.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

The rich schema fully documents the nested field objects, including target references, type-specific value behavior, and permission-related element descriptions. Combined with the read-only and destructive annotations, the description is sufficient for correct invocation; only alternative-selection guidance is missing.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100%: the fields array and its nested target, name, type, value, and element properties all have descriptive text. The description itself does not add parameter-level meaning beyond what the schema already provides.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description 'Fill multiple form fields' clearly identifies the action and resource, and the word 'multiple' helps distinguish it from single-field tools like browser_type. It does not explicitly contrast with sibling tools, but the core purpose is unambiguous.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines2/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

No guidance is provided for when to use this tool instead of alternatives such as browser_type, browser_select_option, or browser_click. The term 'multiple' implies batch usage, but there is no explicit when-to-use or exclusion context.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.