Fill form

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

Annotations only declare readOnlyHint=false and openWorldHint=true, so the description must carry behavioral weight; it usefully explains per-element value coercion (text/textarea vs checkbox/radio/switch vs select). It does not say whether filling is atomic on failure, whether change/blur events fire, or what gets reported back — significant gaps for a mutating tool with no output 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?

Three tight sentences, zero filler, and the batch scope is front-loaded ahead of the value-format rules. Nothing repeats the schema verbatim.

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?

Covers purpose and value typing, but omits failure/partial-application behavior, the need for refs from page_snapshot (only in schema), and any statement about return values. With no output schema, some of that burden lands on the description and is unaddressed.

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%, which sets a baseline of 3, but the description goes beyond it by specifying the accepted value grammar per element type ("true"/"false" for checkboxes, label-or-value for selects). That is real semantic guidance the schema's generic 'Value to set.' does not provide.

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?

States a clear verb+resource ('Fills several form fields') and emphasizes batch semantics ('in one call'), which implicitly distinguishes it from the sibling `type` (single-field) and `select_option` tools. No sibling is named explicitly, so it stops short of a 5.

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?

Batching is implied by 'several form fields in one call', but the description never says when to prefer this over `type`, `press_key`, or `select_option`, nor what to do if a ref is stale. Usage must be inferred from the word 'several'.

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