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

No annotations are provided, so the description must carry the load for behavioral disclosure. It only adds that the expression is 'discarded', which hints at no retention but says nothing about side effects, return values, permissions, or how the parameters are processed. This is clearly insufficient for a mutation-like tool with no annotations.

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 intended action and includes no filler or redundancies. Both sentences are purposeful, but the text is so thin that some key information is missing elsewhere. It is concise rather than verbose, which earns it a high but not perfect score.

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 nine optional parameters, no annotations, and no output schema, the single-sentence description leaves the agent unable to infer how to pass an expression, what the response looks like, or why that expression is evaluated. The description is far too sparse to declare the tool safe for autonomous 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?

Schema coverage is 100%, so every parameter has its own description, and the baseline is therefore 3. The description does not add any meaning to the parameters; in fact, it introduces a concept ('expression') that has no corresponding parameter. This is a missed opportunity but the schema still provides full parameter documentation.

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 states a specific action ('Evaluate a+b style arithmetic') but is vague about what resource or input is used, and no schema parameter represents an arithmetic expression. It does not clearly differentiate from the many sibling shape/check tools, since 'Expression discarded' leaves the operation confusing. Overall it has a purpose, but not a crisp one.

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 about when to use this tool versus any sibling, no prerequisites, and no exclusion cases. The phrase 'a+b style arithmetic' implies a narrow use case, but without an expression parameter or mention of alternatives, the agent is left with no information about when this tool is a better choice than one of the many sibling tools.

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