Choose an option from a dropdown list identified by its label. Returns the chosen option and any resulting page updates.
Choose an option in a dropdown list, a select element, found by its label. Returns the choice made and anything that followed.
| Name | Required | Description | Default |
|---|---|---|---|
| label | Yes | Visible label of the list, such as Country. Part of the label is enough. | |
| option | Yes | Text of the option to choose, exactly as the list shows it. |
Changes observed during successful MCP inspections.
v0.4.6Input schema / properties / label / descriptionAdded value: +"Visible label of the list, such as Country. Part of the label is enough."Input schema / properties / option / descriptionAdded value: +"Text of the option to choose, exactly as the list shows it."v0.4.5Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations are provided, so the description carries the full behavioral burden. It does disclose that the tool 'Returns the choice made and anything that followed,' which is useful post-action information. However, it does not describe potential side effects such as navigation, form submission, or page changes that selecting an option might trigger.
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 two concise sentences with no filler. The core action and locator strategy are front-loaded, and the return behavior is stated succinctly. Every sentence earns its place.
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 simple two-parameter tool with fully documented parameters and no output schema, the description covers purpose, locator method, and return value. It lacks explicit side-effect disclosure, but given the low complexity, the description is largely complete for an agent to call the tool 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 100%, so both parameters are already well documented in the schema. The description adds only marginal semantic value by reiterating that the element is 'found by its label,' which maps to the label parameter. Baseline 3 is 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 and resource: 'Choose an option in a dropdown list, a select element.' It also specifies how the element is found ('by its label'), which clearly distinguishes this tool from siblings like click or fill. The purpose is immediately understandable.
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 context is clear: this tool is for selecting an option within a dropdown or select element. It does not explicitly name sibling alternatives or state when not to use it, but the resource type makes the intended use apparent. This aligns with 'clear context, no exclusions.'
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.