select_option

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

No annotations are provided, so the description carries the full burden. It mentions the return of post-action page_state and that it captures page changes, but it does not disclose potential failures (e.g., dropdown not found) or whether it waits for updates.

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 three sentences, front-loading the purpose, then providing how-to, and concluding with return value. Every sentence is necessary and contributes meaningfully.

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 UI interaction tool with 4 parameters (1 required) and no output schema, the description fully covers how to use it and what to expect (page_state). It is complete for an agent to select the correct option.

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 100% with parameter descriptions. The description adds value by explaining when to use each parameter (e.g., 'Use when value/label are unknown' for index), which goes beyond the schema's structural definitions.

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 selects an option from a <select> dropdown, specifying how to identify the dropdown via CSS selector or @eN ref and how to specify the option by value, label, or index. It distinguishes from sibling tools like click() and fill_form().

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 when to use the tool (for selecting from dropdowns) and how to specify options, but it does not explicitly mention alternatives or when not to use it. However, the context of sibling tools implies click() is for non-dropdown interactions.

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