Gemini Compare Urls Tool

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

readOnlyHint=true already tells the agent this is a safe read, so the bar is lower, but the description adds nothing beyond that — no indication of whether pages are fetched live, whether this incurs cost, or how the two URLs are compared. It does not contradict the annotation.

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?

It is a single tight sentence with zero padding, which is front-loaded by definition. The problem is under-specification rather than bloat, so it neither wastes words nor earns credit for useful density.

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?

An output schema exists, so return values need not be explained, and annotations cover the safety profile. Yet for a comparison tool with an 'aspect' switch (content, design, sentiment, features), the description says nothing about how aspects shape the comparison, leaving a meaningful behavioral gap.

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% and the schema documents url1, url2, model, and aspect (including the comparison modes). The description adds no parameter meaning beyond that, so the baseline 3 is appropriate.

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 specific verb ('Compare') and resource ('URLs'), so it escapes tautology. However, it offers no differentiation from the several sibling URL tools (gemini_analyze_url_tool, gemini_extract_from_url_tool, gemini_youtube_tool), leaving the agent to guess when comparison is the right operation.

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?

There is no guidance on when to use this over the other URL tools, nor any exclusions or prerequisites. The agent can only infer usage from the verb, and the crowded URL-tool sibling set makes that inference risky.

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