browser_select

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

Annotations already indicate readOnlyHint=false, destructiveHint=false, idempotentHint=true, and openWorldHint=true. The description adds meaningful behavioral context beyond annotations: it refuses stale refs, which is a safety-relevant behavior. It also clarifies that selection is by value or label, which is not in the schema. No contradiction with annotations.

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 sentence that front-loads the core action and includes a critical safety qualifier ('refusing a stale ref'). Every word earns its place; no filler or repetition of schema details.

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 tool with no output schema and sparse parameter documentation, the description covers the core action and one behavioral nuance, but leaves gaps: what a 'ref' is, how the option is matched (exact vs partial), and what happens on failure. Given the tool's moderate complexity and the openWorldHint, a bit more context would help an agent invoke it correctly.

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 0%, so the description must compensate. It explains that 'option' is a value or label, which adds meaning. However, it does not explain what 'ref' refers to (presumably a reference to an observed dropdown element) or what 'page_key' is for. With 0% schema coverage, the description only partially compensates for the undocumented parameters.

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 ('Select') and resource ('dropdown option'), and adds a distinguishing detail: it selects by value or label and refuses stale refs. It is clear enough to differentiate from siblings like browser_click or browser_type, though it doesn't explicitly name a sibling alternative.

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 context: use this when you have observed a dropdown option and need to select it, and avoid using it with a stale ref. However, it does not explicitly state when to prefer this over browser_act or browser_click, nor does it describe prerequisites like having observed the dropdown first.

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