arc_close_tab

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

With no annotations provided, the description carries full responsibility for disclosing behavior. It only states 'close the specified tab' without detailing what happens when both parameters are provided, whether multiple tabs can be closed, or how errors are handled. This lack of transparency forces the agent to rely on assumptions.

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, concise sentence that immediately conveys the tool's core function. It is front-loaded and contains no superfluous words, earning its place effectively.

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 simplicity (2 optional parameters, no output schema, no annotations), the description lacks important context such as parameter interaction, behavior when neither parameter is provided, or error states. It is incomplete for a naive agent to use confidently without additional knowledge.

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 the parameters are already documented in the schema. The description adds no additional meaning beyond the schema, making it adequate but not superior. A score of 3 reflects the baseline when the schema sufficiently describes the 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 '指定したタブを閉じる' clearly states the action (close) and the resource (tab), making the tool's purpose immediately understandable. It distinguishes itself from sibling tools like arc_switch_tab or arc_list_tabs by focusing specifically on closing a tab.

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, nor does it explain how to choose between the two parameters (tab_index vs url). There are no usage scenarios or exclusion criteria mentioned.

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