browser_close_tab

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

Without annotations, the description discloses that this is a destructive action (closing a tab) and includes a constraint, but it does not specify error behavior (e.g., if tabId is invalid or if it is the primary tab) or any side effects. Additional transparency would improve this.

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, straightforward sentence with no unnecessary words. It is efficiently front-loaded with the main action and constraint.

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 (one parameter, no output schema), the description covers the core purpose and a constraint, but it lacks parameter explanation and return/error information, making it only partially complete for reliable agent use.

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 has no description for the 'tabId' parameter, and the description does not clarify what the number represents (e.g., index, ID from list_tabs?). With 0% schema coverage, the description fails to add meaning; the agent has no guidance on how to obtain or use tabId.

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 action (close a specific session tab) and includes a key constraint (cannot close the primary tab), which distinguishes it from sibling tools like browser_open_tab or browser_list_tabs.

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 mention that the primary tab cannot be closed provides some guidance on when this tool is usable, but it does not explicitly state when to use it versus alternatives or provide prerequisites or context about tab state.

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