seleniumbase-mcp

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Manage Window

manage_window

Get or change browser window size, position, and state. Set exact dimensions or maximize/minimize to control the viewport during automation.

Instructions

Get or change browser window geometry or state.

Args: action: - "get_rect": Return the current window position and size. - "set_rect": Set x, y, width, and height. All four are required. - "maximize": Maximize the browser window. - "minimize": Minimize the browser window.

x: Horizontal screen position for "set_rect".

y: Vertical screen position for "set_rect".

width: Window width for "set_rect".

height: Window height for "set_rect".

Notes: Use this tool for browser-window geometry and state. Use manage_tabs for switching between browser tabs.

Input Schema

TableJSON Schema

Name	Required	Default
`x`	No
`y`	No
`width`	No
`action`	No	get_rect
`height`	No

Output Schema

TableJSON Schema

Name	Required	Description	Default
`result`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0Sep 15, 2026

TDQS

A4.4/5.0

Behavior3/5

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

No annotations are provided, so the description carries the behavioral burden. It discloses the four actions and the requirement for set_rect, but it does not describe side effects, coordinate units, default action behavior, or return semantics beyond what the schema already shows.

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 well-organized with an Args/Notes split, bullet-style action definitions, and no filler. The most important usage guidance is front-loaded, and each line earns its place.

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?

Given no annotations and a 0% schema description coverage, the description covers the action matrix, parameter meanings, and the key constraint of set_rect. Minor gaps remain, such as coordinate interpretation and default action, but an output schema exists so return-value details are not necessary.

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

Parameters4/5

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

Schema description coverage is 0%, and the description compensates by explaining each parameter and enumerating the action enum. It adds the important rule that set_rect needs x, y, width, and height, though it slightly repeats information already inferable from the parameter names.

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 opening line, 'Get or change browser window geometry or state,' uses a specific verb and resource and clearly scopes the tool. The action list further enumerates the exact operations, making it easy to distinguish from siblings.

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 Notes section explicitly directs the agent to use this tool for window geometry and state, and points to manage_tabs for switching tabs, which provides a clear alternative. It also states that set_rect requires all four coordinates, giving an explicit usage constraint.

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