Resizes the page's window so that the page has specified dimension
Resizes the page's window so that the page has specified dimension
| Name | Required | Description | Default |
|---|---|---|---|
| width | Yes | Page width | |
| height | Yes | Page height | |
| pageId | Yes | Targets a specific page by ID. |
Changes observed during successful MCP inspections.
v0.1.1Input schema / additionalPropertiesPrevious value: -{}New value: +falseInput schema / properties / height / exclusiveMinimumAdded value: +0Input schema / properties / height / maximumAdded value: +9007199254740991Input schema / properties / height / typePrevious value: -"number"New value: +"integer"Input schema / properties / width / exclusiveMinimumAdded value: +0Input schema / properties / width / maximumAdded value: +9007199254740991Input schema / properties / width / typePrevious value: -"number"New value: +"integer"v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations only declare readOnlyHint=false, confirming a mutation, but the description adds nothing about what changes: whether this affects the real browser window or an emulated viewport, whether it persists across navigation, or how it interacts with screenshots and screencasts. For a state-changing tool with no output schema, that leaves the agent guessing about side effects.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
A single, front-loaded sentence with no filler. Minor grammar awkwardness ('specified dimension' should be plural) but nothing extraneous.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
For a three-required-parameter mutation tool with minimal annotations and no output schema, the description should cover units, whether it is the real window or an emulated viewport, and persistence. None of that is present, so an agent cannot fully predict the call's effect.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
Schema description coverage is 100%, so pageId, width and height are already documented, and the baseline of 3 applies. The description adds no meaning beyond the schema — notably it does not state the unit (pixels) or any practical bounds for width/height.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
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 resulting effect ('page has specified dimension'), so the operation is unambiguous. It does not distinguish itself from the sibling 'emulate', which can also change viewport dimensions, leaving overlap unaddressed.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
There is no guidance on when to use this versus alternatives such as 'emulate', nor any prerequisites (e.g., page must be open, effect on active tabs). The agent must infer the usage context entirely from the one-line purpose.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.