Fill multiple web form fields simultaneously by specifying name, type, reference, and value for each. Eliminate repetitive individual inputs and streamline browser automation and testing.
Fill multiple form fields at once
| Name | Required | Description | Default |
|---|---|---|---|
| fields | Yes | Array of form fields to fill |
Changes observed during successful MCP inspections.
v1.1.0Does 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 says 'fill' without revealing whether the tool submits the form, clears existing values, dispatches events, waits for navigation, or has any side effects. This is a significant gap for a mutating browser action.
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?
A single, efficient sentence with no filler words. The core action and scope are front-loaded, making it easy to scan.
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 browser automation tool with no annotations and no output schema, the description is too thin. It doesn't mention prerequisites (e.g., must be on a page with a form), return values, error cases, or whether the operation is atomic. An agent lacks enough context to invoke it reliably.
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 the schema already documents each property thoroughly. The description adds only a high-level 'multiple form fields at once' statement and no extra detail beyond the schema, which meets the baseline but doesn't elevate it.
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 ('fill') and resource ('multiple form fields at once'), clearly distinguishing it from sibling tools like browser_type (single field) and browser_select_option (single dropdown). An agent can immediately tell this is a batch operation for form inputs.
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 phrase 'at once' implies batch usage, contrasting with single-field siblings, but there is no explicit guidance on when to choose this over browser_type or how it differs in behavior. The usage context is implied rather than stated.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.