apple_safari_close_tab

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

Annotations already declare destructiveHint=true and non-idempotent, and the description adds concrete context beyond them: unsaved page input may be lost, and the URL must be a previously observed value (a safety guard against closing the wrong tab). It doesn't say what happens on a URL mismatch, keeping it at 4.

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 clauses with zero waste; the action is front-loaded and the destructive warning follows immediately. Nothing is padded.

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 destructive, no-output-schema, three-parameter tool, the description covers the safety-critical facts: data loss risk and the URL precondition. Missing is how the other two identifiers are sourced and what failure looks like on a stale URL.

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 description coverage is 0%, so the description carries the full burden, yet it only explains expectedUrl ('its previously observed URL'). windowId and tabIndex — where they come from and what values are valid — are left entirely to the bare schema types.

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 states a specific verb and resource ('Close a Safari tab'), which is unambiguous against Safari siblings like list_tabs, get_tab, open_tab, and navigate_tab. It never explicitly contrasts itself with those siblings, so it lands at 4 rather than 5.

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?

It gives a real precondition — 'Requires its previously observed URL' — which tells the agent it must have first observed the tab (via list_tabs/get_tab) before closing. It stops short of naming those prerequisite tools or stating when to prefer this over other tab operations.

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