Unchecks a checkbox or radio control by snapshot reference or CSS selector, with optional page and session targeting for precise browser automation.
Uncheck a checkbox or radio control.
| Name | Required | Description | Default |
|---|---|---|---|
| pageId | No | Defaults to the active page | |
| target | Yes | Snapshot ref (e12) or unique CSS selector | |
| sessionId | No | Defaults to the active session |
Changes observed during successful MCP inspections.
v2026.10.24Input schema / properties / pageId / descriptionPrevious value: -"Stable page ID; defaults to the session active page"New value: +"Defaults to the active page"Input schema / properties / sessionId / descriptionPrevious value: -"Optional session ID; defaults to this MCP client active session"New value: +"Defaults to the active session"Input schema / properties / target / descriptionPrevious value: -"Snapshot ref such as e12, aria-ref=e12, or a unique CSS selector"New value: +"Snapshot ref (e12) or unique CSS selector"v2026.8.14Does 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 not disclose failure modes (e.g., element already unchecked, not visible, or not a checkbox/radio), whether it scrolls into view, or what happens if the target is ambiguous. For a browser mutation tool, this is a significant gap.
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, front-loaded sentence with zero wasted words. It is appropriately sized for a simple, focused browser action.
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 and the schema fully documents its parameters. However, with no annotations and no output schema, the description could do more to state behavioral expectations for the mutation, such as whether it throws on already-unchecked elements or waits for actionability.
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 all three parameters (pageId, target, sessionId) are already documented in the schema. The description adds no extra meaning beyond what the schema provides, which is acceptable at baseline 3.
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 a specific verb ('Uncheck') and resource ('checkbox or radio control'), so an agent can immediately understand the operation. It does not explicitly differentiate itself from the sibling nex_browser_check, but the inverse relationship is obvious from the name.
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 nex_browser_check or other interaction tools, and no mention of preconditions such as the element needing to be currently checked. Usage is only implied by the verb.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.