invisible-playwright-mcp

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browser_type

Replace a browser input field's content with given text in one action, avoiding keystroke events. Use for setting values directly without triggering autocomplete.

Instructions

Fill a field, replacing whatever it holds.

This sets the value rather than typing key by key, so it will not fire the per-keystroke handlers an autocomplete needs. For those, click the field and use browser_press_key.

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": {
      "selector": "<selector>",
      "text": "<text>"
    },
    "name": "browser_type"
  }
}

Input Schema

Name	Required	Description	Default
`text`	Yes
`selector`	Yes

Output Schema

Name	Required	Description	Default
`result`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0Aug 21, 2026

TDQS

A4.4/5.0

Behavior4/5

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

With no annotations, the description carries the burden of behavioral disclosure. It reveals that the tool replaces the field's current value and does not fire per-keystroke handlers, which is a critical trait. It could also mention broader side effects like input/change events, but it covers the key differentiator well.

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

Conciseness5/5

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

The description is two short sentences, with the primary action front-loaded. Every sentence adds value: the first states the purpose, the second provides a key caveat and an alternative. No filler or repetition.

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?

For a simple two-parameter tool that has an output schema, the description covers the essential behavior and the most important exception (autocomplete). It does not address error conditions or focus requirements, but those are not critical given the tool's simplicity and sibling context.

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 description coverage is 0%, so the description must compensate. It indirectly clarifies that 'text' is the value to fill and 'selector' is the target field, but it does not define acceptable selector syntax or text encoding, leaving room for ambiguity.

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

Purpose5/5

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

The description states a specific action and outcome: filling a field and replacing its current content. It clearly differentiates the tool from typing-based tools like browser_press_key by emphasizing that it sets the value rather than typing key by key.

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

Usage Guidelines5/5

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

The description explicitly tells when not to use this tool (when the field needs autocomplete per-keystroke handlers) and names the alternative (click the field and use browser_press_key). This gives agents unambiguous selection criteria.

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

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