tab_close

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It states the operation (close) but does not mention that closing a tab is irreversible, what happens on invalid index, or whether it returns a confirmation. This is a destructive action, and the description offers no warning or detail about side effects.

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 concise sentence that front-loads the primary action and includes the key qualifier about index behavior. There is no filler or redundant information; every word contributes to understanding.

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 single-parameter tool, the description covers the core behavior but omits important operational context such as error handling (out-of-range index), side effects (data loss), and return value. Given no annotations and no output schema, the description should at least hint at the destructive nature and possible failure modes. It is adequate for a basic use case but not fully 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 schema provides a description for the index parameter, but the tool description adds crucial semantics by explaining that omitting the index closes the active tab. This goes beyond the schema's 'Tab index (see tab_list)' by clarifying the default behavior, which is essential for correct invocation.

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) and resource (tab), and specifies the index-based behavior. It distinguishes itself from siblings like tab_open and tab_switch by its verb and target. The mention of 'active one' adds specificity that disambiguates from other tab 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 explains how to specify which tab to close (by index, or default to active), which serves as usage guidance. However, it does not explicitly state when to use this tool versus alternatives like browser_close or tab_switch, nor does it mention any exclusions or prerequisites (e.g., must have tabs open).

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