fill_form

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

With no annotations, the description carries behavioral burden. It discloses supported field types and optional submit, but omits error handling, waiting behavior, and side effects like page navigation after submit. The timeout parameter is mentioned in schema but not described.

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?

Three sentences, no fluff. Front-loaded with purpose, then details. Every sentence adds value.

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 4 parameters and no output schema, the description covers purpose, input format, supported types, and optional submit. Minor gaps: no error handling or post-submit behavior, but sufficient for typical use.

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 50% (fields and submit have descriptions; by and timeout lack). Description repeats schema info for fields and adds context for submit, but does not compensate for missing descriptions of by and timeout. Baseline 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 clearly states the tool fills multiple form fields in a single call with a map of CSS selectors to values. It distinguishes itself from sibling tools like type_text (for single field) by emphasizing batch operation and handling various input types.

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 description provides some usage context (batch filling, handles multiple field types, optional submit) but lacks explicit when-to-use vs alternatives. No mention of when not to use or that single-field operations should use type_text.

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