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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It reveals only that the expression is 'discarded,' but it does not state whether a numeric result is returned, whether the call is side-effect-free, whether it only validates shape, or what happens to the other input fields.

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 very short and front-loaded with the main verb phrase, which is good. However, the second sentence 'Expression discarded' is a fragment that only confuses without a matching schema property, reducing the value of the brevity.

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?

There is no output schema, no annotations, and nine heterogeneous parameters with no explanation of how they relate to the described arithmetic behavior. The definition is fundamentally incomplete: an agent cannot determine which parameter to populate, what response to expect, or how this tool differs from the sibling shape-checking tools.

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%, which normally earns a baseline of 3, but the description actively introduces an 'expression' concept that does not appear anywhere in the schema. Rather than adding meaning to the parameters, it misleads the agent into looking for a non-existent arithmetic-expression field.

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 names a concrete operation, 'Evaluate a+b style arithmetic,' which is more than a tautology. However, 'Expression discarded' muddles whether this tool computes a result or merely checks a shape, and none of the nine input-schema parameters obviously carries an arithmetic expression.

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?

No guidance is given about when to use calc-eval versus the many sibling tools such as normalize-url, validate-json, or search-query-len. The only implied use case is 'a+b style arithmetic,' but no parameter in the schema connects to that use case, so an agent cannot reliably decide when or how to invoke this tool.

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