browser_screenshot

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

With no annotations, the description bears full burden. It discloses that screenshots are slow and heavy, and explains the rect zooming mechanism. However, it does not explicitly state the default capture area (viewport vs full page), though the fullPage parameter in schema partially addresses this.

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?

Four sentences, front-loaded with purpose and usage, then details. Every sentence adds value with no redundancy or fluff.

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 3 parameters, nested objects, and no output schema, the description is fairly complete. It explains the output (file path, pageRect) and zooming workflow. The missing output schema is partially compensated by the description stating the return format. Could briefly mention default viewport capture.

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 coverage is 100%, so the schema already documents all parameters. The description adds value by explaining how rect relates to pageRect from previous screenshots, providing usage context beyond the schema. However, it does not elaborate on selector or fullPage beyond their schema descriptions.

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 uses specific verbs and resources: 'Take a screenshot of the current browser page' and 'Returns the file path to a saved PNG image.' It distinguishes from sibling tools by recommending browser_get_dom and browser_get_page_info for understanding content, clearly stating when to use screenshots.

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 (visual layout verification, debugging, DOM insufficient) and when not to ('slow and heavy — prefer browser_get_dom...'). Also provides guidance on zooming with rect and pageRect coordination.

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