mcp-browser-server

browser_screenshot

Capture a screenshot of the current browser page, optionally select a specific element using a CSS selector or capture the full scrollable page. Returns a base64-encoded PNG.

Instructions

Take a screenshot of the current browser page. Returns a base64-encoded PNG image.

Tool call template

This tool declares no required parameters. Add optional parameters from the input schema as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {},
    "name": "browser_screenshot"
  }
}

Input Schema

Name	Required	Description	Default
`selector`	No	Optional CSS selector to screenshot a specific element
`fullPage`	No	Capture the full scrollable page (default: false)

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0Jun 8, 2026

TDQS

A3.6/5.0

Behavior3/5

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

Without annotations, the description partially carries the burden. It correctly implies a read-only operation but does not explicitly state the lack of side effects, permissions needed, or behavior on failure. The return type is specified, but additional behavioral traits (e.g., non-destructive nature) are not disclosed.

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?

A single, front-loaded sentence efficiently conveys the core action and output format. No extraneous words or information, fitting the tool's simplicity.

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 the tool's low complexity, no annotations, and no output schema, the description covers the essential aspects: what it does and what it returns. However, it omits potential details like error handling or browser requirements, but these are not critical for a straightforward screenshot tool.

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

Parameters3/5

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

Schema description coverage is 100%, so the input schema fully documents both parameters. The description adds no additional meaning beyond what the schema provides, meeting the baseline expectation.

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 clearly states the action ('Take a screenshot of the current browser page') and the return format ('base64-encoded PNG image'). It unambiguously identifies the tool's functionality and distinguishes it from sibling tools, none of which capture screenshots.

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?

The description provides no guidance on when to use this tool versus alternatives. It does not mention prerequisites, limitations, or comparative advantages over sibling tools like browser_get_content or browser_evaluate.

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

Deploy Server