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

No annotations are present, so the description must disclose all behavior. It mentions that the expression is 'discarded', which is useful, but it does not state whether the tool returns a result, produces side effects, or how it handles the many possible inputs in the schema.

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 appropriately short, at two sentences, and the first sentence states the purpose. However, the second sentence is vague and does not clarify the tool semantics, so it does not earn its place with a clear explanation.

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 9 optional parameters and no output schema, the description should explain what input to supply and what the agent can expect back. It is missing this entirely, leaving an agent unable to use the tool correctly.

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% per the context signals, so the schema already documents each parameter. The description adds no information about which of the nine parameters is relevant to the arithmetic evaluation, so the support is at the baseline without further value.

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 says 'Evaluate a+b style arithmetic' but does not explain what evaluating means in this context, nor does it distinguish this from sibling shape-checking tools. The phrase 'Expression discarded' is ambiguous about whether the tool returns a computed value or merely validates the shape.

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 no indication of when to use calc-eval versus the many sibling tools like 'domain-shape' or 'wiki-title-ok'. It does not mention the intended use case, prerequisites, or any alternative.

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