Inspect localhost UI

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

Annotations already mark readOnlyHint=true. The description adds behavioral context: opens URL in headless Chromium, captures outputs, and restricts to local addresses. It does not mention any destructive actions, consistent with the annotation. Slight deduction for not explicitly stating it is read-only beyond the annotation, but the description's detail is sufficient.

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?

The description is front-loaded with the core purpose, followed by output list, use cases, operational guidance, and constraints. Every sentence adds value without repetition or fluff. Length is appropriate for the information 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?

With no output schema, the description adequately explains what is returned (screenshot, errors, DOM snapshot). However, it lacks detail on return format (e.g., image encoding, error structure). Still, for a tool this size, it provides sufficient context to set expectations.

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 extra context beyond schema, e.g., 'Use mobile to debug responsive layouts' for viewport, and implies delay purpose. This warrants a slight above-baseline score.

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 defines the tool's function: 'Gives you eyes on a locally running web app.' It lists specific outputs (screenshot, console errors, DOM snapshot) and directly ties to debugging UI issues. No siblings exist, so differentiation is not required.

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 explicit when-to-use guidance: 'verify or debug UI work instead of guessing' with concrete examples like layout bugs, hydration errors, etc. It also advises reading DOM classes before proposing fixes and notes the address restriction, leaving no ambiguity.

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