browser_close_tab

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

No annotations are provided, so the description carries the full behavioral burden. It says 'close' but not whether closing the last tab ends the session, whether an invalid index errors or is ignored, whether closed tabs are recoverable, or whether unsaved state is lost. For a destructive operation with zero annotation coverage, this is a substantial gap.

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?

A single efficient sentence that front-loads the action and covers both invocation modes without padding. Slightly terse given what is left unexplained, but nothing is wasted.

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?

An output schema exists, so return values need not be described. However, for a destructive single-parameter tool with no annotations, the description omits the edge-case behavior (last tab, invalid index) an agent would need to invoke it safely.

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 0% and the single tab_index parameter has no description. The phrase 'or the current tab' does imply that omitting the parameter defaults to the active tab, which adds real meaning beyond the bare schema, but it never explains acceptable index values or their origin.

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 ('Close') and resource ('tab'), and distinguishes the two modes: a specific tab or the current tab. It is clearly separable from siblings like browser_new_tab and browser_switch_tab, though it doesn't name them explicitly.

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?

No when-to-use guidance, no prerequisites, no mention of how tab_index is obtained (e.g., from browser_tabs) or what happens if it's omitted. The agent must infer that omitting tab_index targets the current tab.

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