Fill Form

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

Annotations already indicate destructiveHint=true and readOnlyHint=false. Description adds 'Sensitivity: filled values may be captured in the DOM, requests, screenshots, traces, or remote application state,' warning about data persistence beyond annotations.

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 with clear flow: usage indication, preconditions, next steps, sensitivity. No unnecessary words.

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, preconditions, next steps, and sensitivity. Output schema exists, so return values are not needed. Could mention minItems constraint for fields array or default timeoutMs, but overall complete for a form-filling tool.

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 0%. Description mentions 'unambiguous field selectors, names, labels, or placeholders' which hints at fields array properties but does not detail timeoutMs or submitSelector. Without schema descriptions, more parameter guidance would be beneficial.

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?

Description clearly states 'Use when multiple form controls must be populated consistently and optionally submitted during a reproduction.' It specifies verb 'fill' and resource 'form', and distinguishes from sibling tools like browser_type (single field).

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?

Preconditions are explicit: 'active page and unambiguous field selectors, names, labels, or placeholders are required; provide only intended test data.' It advises next steps. However, it does not explicitly mention when not to use or name alternatives, though siblings imply differentiation.

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