pages

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

With no annotations, the description carries the full burden of disclosing behavior. It only says 'List all open browser tabs' without clarifying scope (e.g., does it include all sessions or just the default? does it return an empty list or error?), any side effects, or whether it respects leasing. The ambiguity around 'all' versus the optional session parameter is a significant 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?

The description is a single, efficient sentence that front-loads the action. There is zero waste, and it gets straight to the point. Perfect for a simple list operation.

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?

There is no output schema, so the description should explain what the returned list contains (e.g., array of tab objects with titles/URLs). It also doesn't address the behavior across sessions or whether leasing affects the result. For a tool with optional session scoping, the missing details about scope and return format make it incomplete.

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%, and both 'lease' and 'session' have clear descriptions. The tool description adds nothing about parameters, which is acceptable since the schema already explains them. Baseline of 3 is appropriate when the schema does 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 states a specific verb (List) and resource (all open browser tabs), making the core purpose clear. However, it doesn't explicitly differentiate from sibling tools like 'frames' or 'content', though the concept of listing tabs is distinct enough that an agent would likely understand its role without extra clarification.

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 page_new or page_switch. The schema's note about using a unique session name for stateful work gives some context, but that's parameter-level advice, not tool-selection guidance. An agent has to infer that 'pages' is the right call for getting an overview of open tabs.

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