fill_form

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

No annotations are present, so the description carries the burden of behavioral disclosure. It explicitly describes the interaction sequence: each field is found, tapped, then typed into with unicode-safe text. It does not discuss error handling or side effects, but the core behavior is transparent.

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 front-loaded with the purpose, then provides the key mapping, a concrete example, and the underlying behavior. Every sentence contributes useful information with no redundant filler.

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 nested-parameter tool with no annotations and zero schema coverage, the description covers behavior and the `fields` parameter well. The unexplained `serial` parameter is a clear gap, and no alternatives are mentioned. An output schema exists, so omitting return-value details is acceptable, but the parameter gap keeps it from being fully complete.

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?

The description thoroughly explains the `fields` parameter with a concrete example, which is valuable because schema coverage is 0%. However, the optional `serial` parameter is completely unexplained by both the schema and the description, leaving an important parameter gap.

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 opening sentence states a specific action (fill multiple fields) on a specific resource (form fields) in one call. The field mapping and the reference to find_element/ui_dump make the operation unambiguous. It does not explicitly name a sibling like type_into, but the batch nature is clear.

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 'in one call' plus the sequential find-tap-type behavior makes the intended batch-filling context clear. It also tells the agent where to obtain resource-ids via find_element/ui_dump. It does not state when to use a single-field alternative or exclude any cases, but the usage context is still evident.

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