browser_fill_form

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already indicate destructiveHint=true and readOnlyHint=false, so the agent knows this is a mutation. The description adds no additional behavioral context, such as how form filling works, whether it triggers events, or how it uses element references from the page snapshot. It relies entirely on annotations and schema.

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 sentence with no filler words, and the main action is front-loaded. However, it is so minimal that it borders on under-specification, which is why it does not earn a 5.

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 has a complex nested parameter schema and operates on live browser pages, yet the description provides no usage context. It fails to mention that the tool is for batch operations, how targets are resolved, or any behavior around permissions or field types. The schema compensates for parameter details but not for overall operational context.

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 coverage is 100% for the single parameter, and the schema provides rich descriptions for each nested field property (target, name, type, value, element). The description 'Fill multiple form fields' does not add any parameter-specific meaning beyond what the schema already offers, so the baseline of 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 ('Fill') and resource ('multiple form fields'), which clearly conveys the tool's core action. However, it does not distinguish itself from sibling tools like browser_type or browser_select_option, so an agent might need to inspect the schema to know exactly how it differs.

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. Siblings such as browser_type, browser_click, and browser_select_option perform related actions, but the description does not mention when to prefer one over the other, nor any conditions or prerequisites.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.