Sets the value of input, textarea, select, checkbox, or contenteditable elements and optionally submits their form in Safari.
Set the value of an input, textarea, select, checkbox or contenteditable. Optionally submit its form.
| Name | Required | Description | Default |
|---|---|---|---|
| ref | No | ||
| tab | No | Tab id "windowId:tabIndex" from tabs_list. Omit for the active tab of the front window. | |
| value | Yes | ||
| submit | No | ||
| selector | No |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With zero annotations, the description carries the full burden. It does earn credit for disclosing the important side effect that the form may be submitted, which is behavior beyond a plain value set. But it says nothing about how the target element is resolved, what happens if the element is missing or ambiguous, or whether events are dispatched so frameworks register the change.
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?
Two tight sentences, front-loaded with the core action and the covered element types, ending with the optional side effect. Every clause carries information.
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 5-parameter, no-annotation, no-output-schema browser mutation tool, this is under-specified: no element-resolution rule, no error behavior, no mention of what the call returns or how to confirm the value took effect. An agent would have to guess at the ref/selector contract.
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 only 20% — just the 'tab' parameter is documented. The description does not explain the ref-versus-selector choice or precedence, why 'value' accepts string/boolean/number (boolean for checkbox), or what 'submit' actually triggers. It leaves the majority of parameters undocumented in both places.
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?
States a specific verb ('Set the value of') and enumerates the exact element types it handles (input, textarea, select, checkbox, contenteditable), which distinguishes it from the click or press_key siblings. It stops short of naming an alternative or stating the resolution model, so it's clear but not differentiated against siblings by 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?
The element-type list implies when to reach for this tool rather than click or press_key, but usage is only implied. There is no explicit statement of prerequisites (that a ref or selector must first come from find/read_page) and no when-not-to-use guidance.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.