take_screenshot

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

With no annotations provided, the description carries the full burden. It discloses that it uses a real headless browser and that the return value is a base64 string, and it explains the fullPage behavior. This is adequate transparency for a simple screenshot tool, though it does not mention potential limitations like timeouts or access restrictions.

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?

Two sentences with no filler. The primary action and output format are front-loaded, and the optional parameter guidance follows logically. Every word contributes meaning.

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?

For a tool of this simplicity (two parameters, no output schema), the description is largely complete. It covers the return format, the fullPage option, and the general behavior. Minor omissions like error conditions or access requirements are not critical for an agent to invoke it correctly.

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 must compensate. It explains the fullPage parameter ('capture the entire scrollable page') but does not add detail about the 'url' parameter beyond what is obvious from the description ('any URL'). Since url is self-evident and fullPage is clarified, the description adds moderate value but does not fully cover both parameters.

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 states a clear verb ('Captures'), a specific resource ('PNG screenshot of any URL'), and the return type ('base64-encoded string'). It is immediately distinct from the sibling tools (scrape_page, run_visual_test) by its explicit focus on capturing a page image.

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?

The description provides clear context for what the tool does and introduces the fullPage option, but it does not explicitly compare against sibling tools or state when not to use it. The usage is implied — if you need a screenshot, use this — but no alternatives or exclusions are given.

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