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Resize Browser Viewport

resize

Adjust the viewport to a specified width and height to test responsive layouts and catch breakpoint issues during QA checks.

Instructions

Resize the viewport to width and height for responsive checks.

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": {
      "width": "<width>",
      "height": "<height>"
    },
    "name": "resize"
  }
}

Input Schema

NameRequiredDescriptionDefault
widthYes
heightYes

Output Schema

NameRequiredDescriptionDefault
dataNo
run_idYes
stagesNo
statusYes
recoveryNo
operationYes
error_codeYes
session_stateYes
schema_versionNo
progress_omittedNo
progress_delivery_failedNo

Schema Changelog

Changes observed during successful MCP inspections.

  1. Changed3 schema fields changedv0.10.0
    • removedInput schema / properties / height / title
      Removed value: -"Height"
    • removedInput schema / properties / width / title
      Removed value: -"Width"
    • removedInput schema / title
      Removed value: -"resizeArguments"
  2. Changed12 schema fields changed
    • removedOutput schema / properties / data / title
      Removed value: -"Data"
    • removedOutput schema / properties / error_code / title
      Removed value: -"Error Code"
    • removedOutput schema / properties / operation / title
      Removed value: -"Operation"
    • removedOutput schema / properties / progress_delivery_failed / title
      Removed value: -"Progress Delivery Failed"
    • removedOutput schema / properties / progress_omitted / title
      Removed value: -"Progress Omitted"
    • removedOutput schema / properties / recovery / title
      Removed value: -"Recovery"
    • removedOutput schema / properties / run_id / title
      Removed value: -"Run Id"
    • removedOutput schema / properties / schema_version / title
      Removed value: -"Schema Version"
    • removedOutput schema / properties / session_state / title
      Removed value: -"Session State"
    • removedOutput schema / properties / stages / title
      Removed value: -"Stages"
    • removedOutput schema / properties / status / title
      Removed value: -"Status"
    • removedOutput schema / title
      Removed value: -"AgentResult"
  3. Changed14 schema fields changedv0.5.2
    • addedOutput schema / properties / data
      Added value: +{
      +  "additionalProperties": true,
      +  "title": "Data",
      +  "type": "object"
      +}
    • addedOutput schema / properties / error_code
      Added value: +{
      +  "anyOf": [
      +    {
      +      "type": "string"
      +    },
      +    {
      +      "type": "null"
      +    }
      +  ],
      +  "title": "Error Code"
      +}
    • addedOutput schema / properties / operation
      Added value: +{
      +  "title": "Operation",
      +  "type": "string"
      +}
    • addedOutput schema / properties / progress_delivery_failed
      Added value: +{
      +  "default": false,
      +  "title": "Progress Delivery Failed",
      +  "type": "boolean"
      +}
    • addedOutput schema / properties / progress_omitted
      Added value: +{
      +  "default": 0,
      +  "title": "Progress Omitted",
      +  "type": "integer"
      +}
    • addedOutput schema / properties / recovery
      Added value: +{
      +  "items": {
      +    "type": "string"
      +  },
      +  "title": "Recovery",
      +  "type": "array"
      +}
    • removedOutput schema / properties / result
      Removed value: -{
      -  "title": "Result",
      -  "type": "string"
      -}
    • addedOutput schema / properties / run_id
      Added value: +{
      +  "anyOf": [
      +    {
      +      "type": "string"
      +    },
      +    {
      +      "type": "null"
      +    }
      +  ],
      +  "title": "Run Id"
      +}
    • addedOutput schema / properties / schema_version
      Added value: +{
      +  "const": 1,
      +  "default": 1,
      +  "title": "Schema Version",
      +  "type": "integer"
      +}
    • addedOutput schema / properties / session_state
      Added value: +{
      +  "title": "Session State",
      +  "type": "string"
      +}
    • addedOutput schema / properties / stages
      Added value: +{
      +  "items": {
      +    "type": "string"
      +  },
      +  "title": "Stages",
      +  "type": "array"
      +}
    • addedOutput schema / properties / status
      Added value: +{
      +  "enum": [
      +    "completed",
      +    "error"
      +  ],
      +  "title": "Status",
      +  "type": "string"
      +}
    • changedOutput schema / required
      Previous value: -[
      -  "result"
      -]New value: +[
      +  "operation",
      +  "status",
      +  "session_state",
      +  "run_id",
      +  "error_code"
      +]
    • changedOutput schema / title
      Previous value: -"resizeOutput"New value: +"AgentResult"
  4. Addedv0.5.1

TDQS

B3/5.0
Behavior2/5

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

Annotations already declare the safety profile (readOnly=false, destructive=false, openWorld=true), so the bar is lower, but the description adds almost nothing behavioral: no units (pixels vs CSS pixels), no indication that the page reflows/breakpoints trigger, and no mention that an active session is required. The only behavioral hint is the phrase 'responsive checks'.

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?

One compact sentence with the action front-loaded and no filler. It is arguably under-specified rather than padded, but nothing in it is wasted.

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

Completeness3/5

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

An output schema exists, so return values need not be explained, but for a mutation-style viewport tool with 0% schema coverage the description is thin: unit semantics and session prerequisites are absent, leaving the agent to guess at values and preconditions.

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 0% and both width and height are required with bare integer types. The description merely restates the parameter names; it supplies no units, valid ranges, or defaults, so it does not compensate for the missing schema documentation.

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 and resource ('Resize the viewport') plus the two parameters it takes and the reason ('responsive checks'). An agent can tell this is a viewport-dimension setter, though it never contrasts itself with the sibling emulate_device, which likely also changes viewport geometry.

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

Usage Guidelines3/5

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

'for responsive checks' implies the usage context (verifying layouts at different breakpoints), and session siblings such as start_session and emulate_device are adjacent. But there is no explicit when-to-use/when-not or guidance on when to prefer emulate_device presets over a manual width/height.

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