browser_tabs

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

Annotations indicate readOnlyHint=false, openWorldHint=true, and destructiveHint=true, covering key behavioral traits like mutability and potential data loss. The description adds minimal context by listing actions, but doesn't elaborate on specifics like what 'close' destroys, auth needs, or rate limits. It doesn't contradict annotations, so it earns a baseline score for adding some value beyond the structured data.

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 and front-loaded, using a single sentence that efficiently lists all possible actions without any wasted words. Every part of the sentence directly contributes to understanding the tool's scope, making it well-structured and easy to parse.

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's moderate complexity (multiple actions via a parameter), rich annotations, and no output schema, the description is somewhat complete but lacks details on return values or error handling. It covers the basic functionality but doesn't fully compensate for the absence of an output schema, leaving gaps in understanding the tool's full behavior.

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 100%, with clear descriptions for both parameters, including an enum for 'action' and details for 'index'. The description doesn't add meaning beyond the schema, such as explaining the semantics of 'new' versus 'select' or default behaviors. Given the high coverage, a baseline score of 3 is appropriate as the schema handles the heavy lifting.

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 tool's purpose with specific verbs ('list, create, close, or select') and resource ('a browser tab'), making it easy to understand what it does. However, it doesn't explicitly differentiate from sibling tools like 'browser_close' or 'browser_navigate', which handle related but distinct browser operations, so it doesn't reach the highest score.

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 provides no guidance on when to use this tool versus alternatives, such as distinguishing it from 'browser_close' for closing tabs or 'browser_navigate' for creating new tabs. It lacks explicit context, prerequisites, or exclusions, leaving the agent to infer usage based on the action parameter alone.

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