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

No annotations are provided and the description carries zero behavioral information. It does not disclose whether the tool is read-only, mutating, rate-limited, deterministic, or how it handles invalid data. With no annotations and a tautological description, the agent has no insight into the tool's behavior.

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 extremely short but not genuinely concise—it repeats the tool name twice with a colon and provides zero informative content. This is under-specification rather than purposeful brevity, similar to the 'Process' calibration example.

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?

Even considering the zero-parameter schema and lack of output schema, the description is wholly inadequate. An agent cannot determine what inputs to derive from context, what calculation to perform, what format the result takes, or how this tool differs from the sibling 'x402-aspect-ratio'. The description adds no value for correct invocation.

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 input schema has zero parameters, so there is no parameter semantics to explain. Per the rubric, 0 parameters receives a baseline of 4. The description adds no information about parameters, but none is needed since there are none to document.

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 'Aspect Ratio Calc: Aspect Ratio Calc' is a pure tautology—it restates the tool name without any verb, resource, or explanation of what the tool does. It also fails to distinguish itself from the sibling tool 'x402-aspect-ratio', which likely has overlapping functionality.

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 tool, what problem it solves, or how it relates to alternatives like 'x402-aspect-ratio'. The description provides no context about input requirements, output expectations, or decision criteria for selection.

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