Fill multiple form fields in a browser session at once by providing field references, types, and values for textboxes, checkboxes, radios, comboboxes, and sliders.
Fill multiple form fields
| Name | Required | Description | Default |
|---|---|---|---|
| fields | Yes | Fields to fill in | |
| sessionId | No | Target session ID. Omit to use the active session. |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare destructiveHint=true, openWorldHint=true, and readOnlyHint=false, so the safety profile is covered. The description adds no behavioral context beyond annotations, such as what happens on failure, how refs are validated, or whether form submission occurs.
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 short phrase with no verbosity, but it is essentially a restatement of the tool name and provides no structural elaboration. It is concise but arguably too sparse to be considered well-structured for the tool's complexity.
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?
Given the tool is destructive, open-world, and interacts with dynamic web forms, the description lacks necessary context such as when to use it versus browser_type, the need for a page snapshot to obtain refs, or any session-related behavior. Annotations and schema cover safety and parameters, but usage context is missing.
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%, and the schema thoroughly documents the fields array and sessionId. The description adds no parameter-level meaning, so the baseline of 3 applies when the schema does the heavy lifting.
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 and resource: 'fill' and 'multiple form fields.' It is clear what the tool does. However, it does not differentiate from sibling tools like browser_type or browser_select_option, which likely handle single-field or option-specific interactions.
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, no prerequisites such as requiring a page snapshot, and no mention of limitations or exclusions. The description only states the action.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.