screenshot

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

Since no annotations are provided, the description carries the behavioral disclosure burden. It adds meaningful details beyond the schema: it returns a PNG, reuses persistent tabs via tab_id, and can target the current page when url is omitted. It does not mention tab lifecycle side effects when no tab_id is given, but the disclosed behavior is substantial.

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 core purpose and return type are front-loaded, followed by the key tab_id usage caveat. Every sentence earns its place.

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 with 7 optional parameters and no output schema, the description provides sufficient invocation context: what it captures, what it returns, and how tab_id interacts with url. Minor gaps remain around combining url and tab_id simultaneously and what happens when neither is provided, but individual parameter details are covered by the schema.

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 baseline is met. The description adds cross-parameter meaning by clarifying that url is optional when tab_id is provided and that a selector can target a specific element. This relationship is not fully apparent from the individual 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 opens with a specific verb and resource: 'Take a screenshot of a web page or a specific element.' The output format is also stated ('Returns a PNG image'), which clearly differentiates it from sibling content-fetching tools like fetch_page or fetch_readable that return HTML/text.

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 gives clear usage context for the persistent-session mode: when tab_id is provided, url is optional and the current page is captured. It does not explicitly contrast against fetch_page or web_search, but it provides enough operational guidance for when to use a tab_id versus a URL.

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