close_page

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

The annotation readOnlyHint=false already signals that this is a mutating operation, and the description's 'Close tab' is consistent with that. However, the description adds no beyond-annotation context about edge cases (e.g., closing the last tab), side effects, or error behavior, so it meets the minimum but doesn't enrich the agent's understanding.

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, compact sentence that immediately states the action and target. There is no redundant information, fluff, or nested structure. It is perfectly front-loaded and appropriate for a tool with one parameter.

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?

While the tool is simple (one parameter, no output schema), the description lacks key contextual details such as how to obtain the tab index (e.g., via list_pages) or what happens if the index is invalid. There is no mention of tie-ins to sibling tools, leaving the agent to infer the workflow. For a minimal one-liner, it's adequate but not complete.

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 input schema already provides a 100% description for pageIdx ('Tab index to close'), and the description's 'by index' adds no additional meaning. Since schema coverage is high, the baseline is 3, and the description does not improve clarity beyond that.

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 'Close tab by index' has a specific verb (close) and resource (tab), and the method (by index) distinguishes it from sibling tools like select_page or navigate_page. It is immediately clear what the tool does and how it differs from other page-related operations.

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 after calling list_pages to obtain the tab index, or in contrast to other tab-manipulation tools. There are no prerequisites, exclusions, or explicit usage context—only a functional statement.

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