Select a dropdown option by providing a CSS selector and the desired value, enabling precise control over form fields in a real browser.
Select an option in a dropdown.
| Name | Required | Description | Default |
|---|---|---|---|
| value | Yes | Value of the option to select | |
| selector | Yes | CSS selector of the select element |
| Name | Required | Description | Default |
|---|---|---|---|
| result | Yes |
Changes observed during successful MCP inspections.
v0.3.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries the full burden of behavioral disclosure. It only states the basic action and does not mention whether the selection triggers change/input events, whether the element must be visible or enabled, or how 'value' is matched against the option (value attribute vs. label).
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 clear, front-loaded sentence with no filler or redundancy. For a simple tool with two well-named parameters, this level of conciseness is appropriate.
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?
The tool is simple, has full schema coverage, and an output schema exists, so the description is minimally viable for an agent to invoke it. However, it lacks behavioral context such as event behavior and value-matching semantics, and the absence of annotations leaves some operational details unspecified.
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?
The input schema documents both 'selector' and 'value' with 100% coverage, so the schema already defines parameter meaning. The description adds no additional parameter context beyond the schema, making the baseline 3 appropriate.
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 uses a specific verb ('Select') and a clear resource ('an option in a <select> dropdown'), which unambiguously identifies the operation. It also implicitly distinguishes this tool from sibling tools like browser_click and browser_type because it targets the select element's option-selection behavior.
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?
There is no guidance on when to use this tool versus alternatives, and no exclusion or prerequisite information is provided. The intended usage must be inferred entirely from the tool name and the one-line description.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.