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Python
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Capture layered page snapshots

browser_snapshot_layers
Read-only

Captures multiple 1280x800 PNG snapshots from the top of the current page to cover several viewports at once, while leaving the session scroll position unchanged.

Instructions

Captures up to max_layers PNGs from the top of the current document, one 1280x800 viewport per layer, without changing the session scroll position. Use this for multi-viewport page coverage; use browser_screenshot for only the current viewport. An omitted session_id targets the active/default session. Returns layer count, offsets, dimensions, and base64 PNG data; max_layers defaults to 3 and is capped at 10.

Input Schema

TableJSON Schema
NameRequiredDescriptionDefault
max_layersNoMaximum number of screen-sized viewport layers to capture (default 3).
session_idNoOptional browser tab/session identifier.

Output Schema

TableJSON Schema
NameRequiredDescriptionDefault

No arguments

Schema Changelog

Changes observed during successful MCP inspections.

  1. Changed1 schema field changedv1.3.5
    • changedOutput schema / (root)
      Previous value: -nullNew value: +{
+  "additionalProperties": true,
+  "type": "object"
+}
  2. First observedv1.3.2

TDQS

A4.9/5.0
Behavior5/5

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

Annotations already declare readOnlyHint=true and destructiveHint=false. The description adds valuable traits beyond those: it captures from the top, uses a fixed 1280x800 viewport per layer, avoids changing session scroll position, and lists the returned data shape. This is rich behavioral context for an agent deciding whether invocation has 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.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Three sentences with no filler. The first explains how the tool operates, the second gives usage routing, and the third covers defaults and return values. Information is front-loaded and every sentence earns its place.

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?

With only two optional parameters, 100% schema coverage, rich annotations, and an output schema present, the description supplies all necessary behavioral and selection context. An agent can confidently decide when to invoke it and what to expect.

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?

Schema coverage is 100%, so the baseline is 3. The description adds meaning by explaining that an omitted session_id targets the active/default session and that max_layers defaults to 3 and is capped at 10, which is not fully specified in the schema.

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 names a specific action ('Captures'), a precise resource ('layers of the current document'), and the operational details (1280x800 viewport per layer, from the top). It explicitly differentiates itself from browser_screenshot, so an agent can disambiguate without opening schemas.

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?

It states exactly when to use this tool ('multi-viewport page coverage') and names the alternative ('browser_screenshot for only the current viewport'). It also clarifies the behavior of an omitted session_id, giving complete selection guidance.

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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