browser_select_option

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

With no annotations, the description carries the behavioral burden and does a good job: it discloses that this triggers a genuine page-visible interaction unlike browser_evaluate, and it explains the browser-scoping rule ('main' default, 'support' shares nothing). It doesn't say what happens when the option is absent or how it waits for readiness, so it stops short of full disclosure.

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?

Three short paragraphs, front-loaded with the core action, then the alternative-selection reasoning, then the browser-scoping caveat. Every sentence carries information; no filler.

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 3-parameter tool with an output schema (so return values need no explanation), the description covers purpose, alternatives, and the browser parameter's semantics. Failure behavior (option not found, timing) is the only notable omission.

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 0%, so the description must compensate. It clarifies that `value` matches either the visible label or the underlying value, and explains `browser` (main vs support, isolated state). Only `selector` is left to inference as a standard CSS selector.

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 (choose) and resource (option in a `<select>` dropdown) plus the two accepted addressing modes (visible label or value). An agent can immediately distinguish this from generic siblings like browser_click or browser_evaluate.

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?

It explicitly names the alternatives (clicking the dropdown plus arrow keys, and browser_evaluate) and gives the reason each is inferior — arrow keys can't confirm which row landed, and evaluate sets the value without a real page interaction. This is explicit when-to-use/when-not guidance.

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