close_page

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

The description discloses a key constraint ('The last open page cannot be closed'), which adds value beyond annotations. However, readOnlyHint: false already indicates mutation, and the description doesn't elaborate on error behavior, side effects, or whether the operation can be undone. The added constraint justifies a mid-score.

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 — two short sentences that front-load the main action and then state the key limitation. Every word earns its place, with no filler or redundancy.

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 tool with a single well-documented parameter and no output schema, the description covers the core behavior and an important edge case. It omits what happens when an invalid pageId is provided or whether the browser state changes, but these are secondary for this simple mutation operation.

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 100% coverage for the single parameter, including a description that tells the agent to call list_pages. The tool description adds the phrase 'by its index', which could be interpreted as positional rather than ID-based, potentially causing confusion. Overall, the description does not improve parameter clarity beyond what the schema already provides.

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 ('Closes the page') and the resource ('page'), with a specific scope ('by its index'). It distinguishes itself from siblings like new_page and select_page. However, 'index' is potentially ambiguous because the schema parameter is called 'pageId', which could imply a stable identifier rather than a positional index.

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?

There is no explicit guidance on when to use this tool or when to prefer alternatives. The schema hints to call list_pages to obtain page IDs, but the description itself doesn't mention that workflow or compare with sibling tools.

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