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resize_page

Resize the browser window to exact width and height for responsive testing or screenshots. Optionally target a specific page by ID.

Instructions

Resizes the page's window so that the page has the specified dimension

Input Schema

TableJSON Schema
NameRequiredDescriptionDefault
widthYes
heightYes
pageIdNoTargets a specific page by ID. Defaults to the selected page.

Schema Changelog

Changes observed during successful MCP inspections.

  1. First observedv0.4.3

TDQS

C2.7/5.0
Behavior2/5

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

No annotations are provided, so the description carries the full burden. It does not disclose units, whether the resize is persistent or session-scoped, whether it requires the page to be attached/selected, or what happens to non-targeted pages.

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?

A single efficient sentence with the action front-loaded and no filler. It is not padded, though it is also thin.

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

Completeness2/5

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

For a mutation tool with no annotations, no output schema, and 33% schema coverage, the description omits too much: units, scope (which pages), persistence, and side effects. The schema's default-to-selected-page note is the only coverage of targeting.

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

Parameters2/5

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

Schema description coverage is only 33% – only `pageId` is documented in the schema. The description says 'specified dimension' but never clarifies units (px?), valid ranges, or the width/height semantics, so it fails to compensate for the uncovered parameters.

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?

States a specific verb (resizes) and resource (the page's window) with the outcome (page has the specified dimension). An agent can tell it apart from most siblings, though the phrasing 'page's window' is ambiguous versus viewport emulation handled by the sibling `emulate`.

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 when-to-use guidance, no prerequisites, and no mention of alternatives such as `emulate` for viewport/device resizing. The agent must infer the context entirely from the name.

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