capture-element

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

No annotations are provided, so the description carries the full behavioral burden. It only states the purpose and the efficiency aspect (not rendering entire page). It does not disclose what happens if the selector is not found, whether it waits for the element, or any side effects. The description adds almost nothing beyond the schema, which already documents parameters.

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?

The description is a single, front-loaded sentence that immediately states the action and purpose. Every word contributes to the tool's function, with no filler or redundancy.

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's complexity (12 parameters, 2 required, no output schema, no annotations), the description is minimal. It does not explain return behavior (presumably an image), error handling, or constraints like element visibility. An agent might need more guidance on how to use it correctly, such as whether the element must be in the viewport or if scrolling is handled.

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 100%, so every parameter already has a description. The tool description itself does not add any extra meaning about parameters, so the baseline 3 applies. It does not clarify relationships between parameters or typical usage patterns.

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 exactly what the tool does: capture an element via CSS selector, with concrete examples (headers, articles, widgets). It also differentiates itself by noting it avoids rendering the entire page, which hints at its distinct role among siblings like render-screenshot and get-screenshot.

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: when you need a specific DOM element like a header or widget. It does not explicitly name alternatives or state when not to use it, but the phrase 'without rendering the entire page' implies a contrast with full-page capture tools, providing context without explicit exclusions.

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