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

Annotations only state not read-only and not destructive. Description adds key behavioral traits: clears then types, dispatches input/change events for React controlled components. This is valuable context 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?

Two sentences with no wasted words. Purpose is front-loaded, and key details are efficiently conveyed.

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?

No output schema exists, but the description covers the core behavior, parameter options, and alternative tool usage. Sufficient for an agent to understand when and how to use this 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 coverage is 100% with descriptions. The description elaborates on 'fields' usage and explains the fill behavior (clears then types) but does not add significant detail for each parameter beyond the 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 it sets the value of form fields via Playwright locator.fill, specifying input/textarea/select. It distinguishes from the sibling 'type' tool by noting when to use type instead.

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?

Provides explicit guidance: 'Use `type` instead only for inputs that require per-keystroke keydown events.' Also mentions using 'fields' for multiple inputs. Lacks explicit 'when not to use' but clearly differentiates from sibling.

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