browser_close_tab

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

The destructiveHint annotation already marks this as destructive, and the description adds valuable behavioral context beyond it by stating "Refuses to close the last tab." This is a meaningful safety behavior that is not encoded in the schema or annotations, so the description earns credit for transparency.

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 two short sentences with zero filler. The action and required id source are front-loaded, and the important safety refusal is stated second without redundancy or unnecessary detail.

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 simple one-parameter destructive tool, the description covers the action, the id source, and the last-tab refusal, which is sufficient to invoke it correctly. It does not explicitly route to sibling tools or describe the result, but the output schema is absent and the tool is simple enough that this is only a minor gap.

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 schema only defines id as a string with no description, and schema description coverage is 0%. The description compensates by specifying that the id comes from browser_status and is used to select the tab to close, giving the single parameter enough semantic grounding for correct invocation.

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 the verb and resource: "Close a tab by id from browser_status." It is specific enough to understand the tool's role, but it does not explicitly distinguish itself from the sibling browser_close, so the differentiation relies on the tool name and context rather than the description.

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: use an id obtained from browser_status, and the tool refuses to close the last tab. However, it does not explicitly state when to prefer this tool over alternatives like browser_close or browser_switch_tab, so no exclusions or alternative routing are provided.

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