fill_form

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

No annotations are provided, so the description must fully disclose behavior. It states fields are filled and optionally submits, but contradicts the schema: the description implies each field entry must have 'ref or CSS selector', yet the schema only requires 'text'. It does not explain what happens if no ref/selector is given, or error handling for invalid selectors.

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?

Only two sentences, front-loaded with the core purpose. No redundant or irrelevant information. Every word earns its place.

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 is relatively simple and has no output schema. The description covers the key actions (filling fields and optional submit). However, it lacks details like whether it waits for page updates or handles hidden fields, but these are minor given the complexity.

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 baseline is 3. The description adds context that fields are batched and submitted together, but does not resolve the ambiguity between description and schema regarding required identifiers. It adds marginal value beyond schema.

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 verb 'Fill' and resource 'multiple form fields', distinguishing it from siblings like 'type_text' (single field) and 'type_and_submit' (includes submit). The 'in one call' emphasizes batching.

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 basic usage: 'Provide an array of field entries... Optionally specify a submit button'. However, it does not explicitly compare with alternatives (e.g., when to use 'type_text' vs. 'fill_form') or mention prerequisites like needing a tab with a loaded page.

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