arc_get_computed_styles

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

With no annotations provided, the description bears full responsibility for behavioral disclosure, but it only states what the tool does. It fails to mention that this is a read-only operation, potential side effects, or required permissions, leaving the agent uninformed about safety or 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?

The description is extremely concise at a single sentence, and it front-loads the purpose. While it could include more details without becoming verbose, the brevity is appropriate for a straightforward tool and avoids unnecessary clutter.

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 lack of output schema and annotations, the description is incomplete. It does not explain what the computed styles output contains, how it is structured, or whether multiple elements can be selected. The agent may struggle to interpret the return value 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 100%, so baseline is 3. The description adds no extra meaning beyond the schema's parameter descriptions, which already define 'selector' and 'tab_index' adequately. The tool does not benefit from further elaboration on parameter usage.

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 '要素の計算済みスタイルを取得する' clearly states the tool retrieves computed styles of an element. Among a large set of sibling tools, it uniquely identifies its function, differentiating from other 'get' tools like arc_get_active_tab or arc_get_cookies.

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, such as arc_get_element_changes for tracking style changes or arc_get_page_content for full page data. It lacks any context about prerequisites or scenarios.

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