close_tab

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

The description states it closes the tab and returns a short confirmation, but without annotations, it lacks details on potential side effects (e.g., unsaved data loss) or prerequisites (e.g., tab must be opened by open_tab). It is adequate but minimal.

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, with two sentences plus a structured Args/Returns section. Every sentence is necessary, and important information is front-loaded.

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 required parameter) and the presence of an output schema (returning a short confirmation), the description covers purpose, usage, parameter, and return value. It is mostly complete, though it could mention handling of tabs not opened by open_tab.

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 description adds meaning to the tab_id parameter by noting it is 'the handle returned by open_tab,' which is not present in the schema (which only specifies type string). This helps the agent understand the origin and usage of the parameter.

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 persistent tab', verb+resource) and specifies that it applies to tabs opened with open_tab, distinguishing it from the sibling close_all_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 description explicitly says 'Call this when you have finished interacting with a page, to free the browser tab,' providing clear usage context. It does not explicitly exclude alternative scenarios or mention when not to use it, but the guidance is sufficient.

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