zen_computed_style

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

No annotations are provided, so the description must carry the full burden. It states the tool returns computed CSS, implying a read operation, but does not disclose any behavioral traits such as whether it requires the element to be visible, what happens on error, or if the result is a snapshot. The mention of a 'layout-relevant set' is vague and lacks detail.

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 communicates the core purpose and default behavior without any unnecessary words. It earns its place with direct information.

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 has 3 parameters with no schema descriptions, no output schema, and no annotations, the description is insufficient. It does not specify return format, error scenarios, or how the default property set is defined. The agent lacks enough context to use the tool reliably.

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?

The input schema has 0% description coverage, so the description must compensate. The phrase 'Defaults to the layout-relevant set' hints that the 'properties' parameter is optional and a default set is used when omitted. However, it fails to explain the 'selector' parameter (e.g., what format? CSS selector?), or the 'tab_id' parameter (e.g., which tab context?). This leaves significant interpretation gaps.

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 'Return computed CSS for an element' with a specific verb and resource. It mentions the default behavior ('Defaults to the layout-relevant set'), but does not elaborate on what that set includes, which slightly reduces clarity. The tool name 'zen_computed_style' is descriptive, and there are no sibling tools with overlapping names, so differentiation is not a concern.

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 no guidance on when to use this tool versus alternatives. It does not mention when not to use it, nor does it reference any related tools (e.g., zen_dom or zen_html for raw HTML/DOM data). This omission leaves the agent without context for selection.

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