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Mehmoodqureshi

chrome-mcp

by Mehmoodqureshi
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screenshot

Capture a webpage or element screenshot from a Chrome tab, with options for format, quality, scale, and full-page capture.

Instructions

Capture a screenshot (page or element). Default is JPEG (quality 70) at CSS-pixel size, which is several times smaller than PNG and reads fine. Pass format:"png" for lossless, quality 1-100 for JPEG, scale 2 for device pixels on a Retina display or 0.5 to shrink.

Input Schema

TableJSON Schema
NameRequiredDescriptionDefault
refNoElement ref from a snapshot
scaleNo
tabIdNoTab id (default: active tab)
formatNo
frameIdNoFrame id from frames_list
qualityNo
fullPageNo
selectorNoCSS selector (or pass ref)
allFramesNoAct on the first match in ANY frame (the element may be in an iframe)

Schema Changelog

Changes observed during successful MCP inspections.

  1. Changed5 schema fields changedv0.9.5
    • changedInput schema / properties / allFrames / description
      Previous value: -"Search every frame of the tab and act on the first that matches - use when a selector should match but does not (the element is in an iframe)"New value: +"Act on the first match in ANY frame (the element may be in an iframe)"
    • changedInput schema / properties / frameId / description
      Previous value: -"Act inside this frame (ids come from frames_list)"New value: +"Frame id from frames_list"
    • changedInput schema / properties / ref / description
      Previous value: -"Element ref from a prior read (exactly one of selector|ref)"New value: +"Element ref from a snapshot"
    • changedInput schema / properties / selector / description
      Previous value: -"CSS selector (exactly one of selector|ref)"New value: +"CSS selector (or pass ref)"
    • changedInput schema / properties / tabId / description
      Previous value: -"Target tab id (defaults to the active tab)"New value: +"Tab id (default: active tab)"
  2. Changed3 schema fields changedv0.9.3
    • addedInput schema / properties / format
      Added value: +{
+  "enum": [
+    "jpeg",
+    "png"
+  ],
+  "type": "string"
+}
    • addedInput schema / properties / quality
      Added value: +{
+  "type": "number"
+}
    • addedInput schema / properties / scale
      Added value: +{
+  "type": "number"
+}
  3. Changed2 schema fields changedv0.7.0
    • addedInput schema / properties / allFrames
      Added value: +{
+  "description": "Search every frame of the tab and act on the first that matches - use when a selector should match but does not (the element is in an iframe)",
+  "type": "boolean"
+}
    • addedInput schema / properties / frameId
      Added value: +{
+  "description": "Act inside this frame (ids come from frames_list)",
+  "type": "number"
+}
  4. First observedv0.6.2

TDQS

A4/5.0
Behavior4/5

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

With no annotations, the description carries the behavioral burden fall. It usefully discloses the default JPEG quality 70, CSS-pixel size, file-size tradeoff, and how to adjust format, quality, and scale. However, it does not state what the tool returns (file path, base64, etc.) or the default for fullPage, which is a notable gap.

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?

Two sentences, with the purpose front-loaded and no repeated schema content. The phrase 'reads fine' is slightly vague and could be removed, but the overall structure is efficient and informative.

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?

For a tool with 9 optional parameters and no output schema, the description covers the core format/quality/scale behavior but omits important execution context: fullPage default, ref-vs-selector precedence, and return value format. The schema fills some gaps (tabId, frameId, allFrames), but an agent cannot fully predict the tool's output or default behavior.

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?

The schema covers only 56% of parameters (5 of 9 have descriptions). The description compensates by explaining format ('png' for lossless), quality (1-100 for JPEG), and scale (2 for Retina, 0.5 to shrink) — all of which lack schema descriptions. It does not explain fullPage, but that parameter is relatively self-explanatory.

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 opens with a specific verb and resource: 'Capture a screenshot (page or element).' This clearly defines the tool's function and distinguishes it from siblings like print_pdf or snapshot. The additional details about format and scale further clarify that this is a visual pixel capture tool.

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?

The description implies when to use the tool (when a screenshot is needed) and gives usage hints for scale and format, but it does not explicitly contrast with alternatives such as print_pdf for PDF output or snapshot for DOM extraction. Exclusion criteria are absent, so the guidance is only implicit.

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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