CallMeter

capture.screenshot

Read-onlyIdempotent

Render a public URL to a PNG/JPEG screenshot for vision, QA, or audit evidence. Call when you need pixels — not structured text (use extract.webpage) and not PDF bytes (use extract.pdf). Inputs: required url; optional viewport {width,height}, fullPage, format=png|jpeg. Viewport capped; SSRF and robots checks refuse unsafe URLs. Outputs image metadata + base64. Paid (~10 credits / $0.10) via prepaid key or x402.

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": {
      "url": "<url>"
    },
    "name": "capture.screenshot"
  }
}

Input Schema

Name	Required	Description
`url`	Yes	Public http(s) URL to screenshot. Example: https://example.com
`format`	No	Image format. Example: png
`fullPage`	No	If true, capture full scrollable page. Example: false
`viewport`	No	Viewport size within caps (width 320–1920, height 320–1080). Example: {"width":1280,"height":800}

Output Schema

Name	Required	Description	Default
No arguments

Schema Changelog

Changes observed during successful MCP inspections.

First observedSep 10, 2026

TDQS

A4.7/5.0

Behavior5/5

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

Annotations cover safety (readOnly, idempotent, non-destructive), but the description adds substantial context beyond them: SSRF and robots checks that refuse unsafe URLs, viewport caps, output shape (image metadata + base64), and pricing (~10 credits / $0.10) with payment mechanisms (prepaid key or x402). This is the kind of cost and authorization info annotations cannot express.

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?

Dense but front-loaded: purpose first, then routing, then inputs, then safety, then cost. Each sentence carries distinct, actionable information with no filler.

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

Completeness5/5

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

Complete for a 4-param tool with an output schema. Safety, cost, alternatives, and input summary are all present; the output schema handles return values, so brief mention of metadata+base64 suffices.

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 coverage is 100%, so the schema already documents url, format, fullPage, and viewport with caps. The description's input summary largely restates the schema; the only added nuance is 'viewport capped,' which the schema already encodes via min/max. Baseline 3 is appropriate.

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?

States a specific verb and resource ('Render a public URL to a PNG/JPEG screenshot') and immediately distinguishes itself from extract.webpage and extract.pdf. An agent can tell exactly what this produces without opening the schema.

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

Usage Guidelines5/5

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

Explicitly says when to call ('when you need pixels') and names both alternatives to use instead for structured text and PDF bytes. The exclusion conditions are concrete and tied to sibling tools.

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

All CallMeter tools Inspect

Try in Browser

Claude Code, inside the Godot 4 editorFlockbay puts an AI agent in the real Godot 4 editor: it writes GDScript, runs your game and fixes what breaks. Free, or bring your own Claude Code or Codex.flockbay.comAd

Glama MCP Gateway

Add one secure layer between your agents and this server.

Resources

Need Help?