close_tab

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It adds useful context about what happens when closing the last tab (navigates to 'about:blank'), which is a behavioral trait not inferable from the schema. However, it doesn't cover other aspects like error handling, permissions needed, or the effect on browser state beyond this specific case, leaving gaps 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?

The description is extremely concise with a single sentence that is front-loaded with the core action ('Close a specific tab') and adds a conditional behavioral note. Every word earns its place, and there is no redundancy or unnecessary elaboration, making it highly efficient.

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?

Given the tool has an output schema (which likely covers return values), the description doesn't need to explain outputs. However, as a mutation tool with no annotations and 0% schema coverage, the description is incomplete: it lacks parameter details, error conditions, and broader behavioral context. The added note about the last tab scenario is helpful but insufficient for full completeness.

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 input schema has 0% description coverage, and the tool description provides no information about the parameters (session_id and page_id). The description does not compensate for this lack by explaining what these parameters mean, how to obtain them, or their roles in identifying the tab to close, resulting in inadequate parameter semantics.

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 ('Close a specific tab') and the resource ('tab'), making the purpose immediately understandable. It distinguishes itself from sibling tools like 'close_all_instances' or 'close_instance' by focusing on individual tabs. However, it doesn't explicitly differentiate from 'switch_tab' in terms of closing vs. switching, which slightly reduces specificity.

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 usage by mentioning the condition 'if the tab is the last one, it will goto about:blank', which suggests when this tool might be appropriate (e.g., for closing tabs in a browser session). However, it lacks explicit guidance on when to use this vs. alternatives like 'close_all_instances' or 'close_instance', and no prerequisites or exclusions are stated, leaving some ambiguity.

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