close_page

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

Annotations only supply readOnlyHint=false, so the description carries most of the burden and does add real behavioral value by disclosing the failure case that the last open page cannot be closed. It stops short of saying whether page state is destroyed or recoverable, which would be useful for a mutation tool.

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?

Two short sentences, purpose front-loaded, constraint second. Nothing extraneous and nothing buried.

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 single-parameter tool with no output schema and only a readOnlyHint annotation, the description covers purpose and the key failure condition adequately. It could note the effect on browser state after closing, but that is 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?

Schema coverage is 100% and the schema already explains pageId fully, including the hint to call list_pages, so the baseline is 3. The description's 'by its index' wording adds no detail and mildly conflicts with the schema's 'ID' framing.

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?

States a specific verb and resource ('Closes the page') that clearly distinguishes it from siblings like new_page, select_page, and navigate_page. The qualifier 'by its index' is slightly at odds with the schema's pageId terminology, but the core purpose is unambiguous.

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 implies the tool's use (closing an open page) and adds one important constraint — the last open page cannot be closed — but never states when to prefer this over alternatives or what prerequisites exist. Usage is inferable rather than explicit.

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