compare_with_screenshot

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

No annotations are provided, yet the description does not disclose behavioral traits such as return format, side effects, or whether it is read-only. It only states the comparison purpose, leaving the agent uninformed about what happens when the tool is invoked.

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 sentence that conveys the core purpose without redundancy. Every word contributes to understanding, making it highly concise.

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 description lacks information about output or return value, which is critical since there is no output schema. It also does not clarify what 'compare' yields (e.g., pass/fail, metrics) or how it relates to performance testing, leaving a significant completeness 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?

The tool has zero parameters, so the schema provides no parameter information and the baseline is 4. The description does not need to add parameter semantics, and it correctly omits any since there are none.

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 uses the specific verb 'compare' and identifies the resources (virtual canvas data size, screenshot) and the context (performance testing), making it clear what the tool does. It distinguishes itself from sibling tools like get_performance_metrics by focusing on comparison rather than measurement.

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 (performance testing) but does not explicitly state when to use this tool over siblings or any exclusions. There is no mention of alternatives, so it earns a 4 for clear context without explicit exclusions.

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