compare_pages

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It only says 'visual diff' without explaining side effects, prerequisites, or how the comparison works. It does not mention whether the tool modifies state, requires a prior screenshot, or how it handles both previousPath and previousUrl.

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 a single, front-loaded sentence with an emoji that concisely conveys the core purpose. It uses zero wasted words and is appropriately sized for the tool's simplicity.

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 has 4 optional parameters and no output schema. The description is brief and does not explain return values, parameter interactions (e.g., whether previousPath and previousUrl are mutually exclusive), or potential error conditions. While the core purpose is clear, the lack of output details and usage nuances makes it somewhat incomplete for a tool with this parameter count.

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 all parameters having descriptions, so the baseline is 3. The description adds marginal value by mentioning 'previous screenshot or URL', which maps to previousPath and previousUrl, but it does not clarify relationships like mutual exclusivity or the purpose of highlightChanges beyond the schema already provides.

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 this tool performs a visual diff between the current page and a previous screenshot or URL. It specifically identifies the resource (page state) and the action (visual diff), distinguishing it from sibling tools like browser_take_screenshot which captures without comparing.

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 clear context that this tool is for comparing the current page state to a historical reference (screenshot or URL). It does not explicitly name alternatives or exclusions, but the purpose is clear enough to infer when it should be used.

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