browser_screenshot

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

No annotations are provided, so the description must cover behavioral aspects. It explains the output (file path to PNG, element count) and that it captures an annotated screenshot. While it doesn't explicitly state that it is read-only or has no side effects, the nature of a screenshot implies no mutation. Minor lack of explicit safety disclosure.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

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

Description is concise at 6 sentences, with no redundant information. It is front-loaded with the main purpose, followed by details on element numbering, usage guidance, return value, and arguments. Every sentence contributes value.

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

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

Given the tool is a screenshot with overlays, the description covers purpose, usage, parameters, and return value. The existence of an output schema (not shown but signaled) reduces the need to detail return structure. It lacks error conditions or permissions, but for a browser tool these are often implied. Adequately complete.

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

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

Schema description coverage is 0%, so the description adds critical meaning. It explains page_id as 'Target page ID' and full_page as 'Capture entire scrollable page (default: viewport only).' This goes beyond the schema's bare titles, providing functional context for each parameter.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the action: 'Take an annotated screenshot with element indices overlaid.' It specifies the resource (browser page) and the key feature (annotations with element indices), distinguishing it from sibling tools like browser_snapshot which is text-based.

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

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

Explicitly states when to use: 'Use when you need VISUAL context — images, charts, CAPTCHAs, or layout.' Also advises when not to use: 'For most interactions, prefer browser_snapshot() instead.' This provides clear guidance and an alternative.

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