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

With no annotations provided, the description must carry the burden of explaining behavior, but it only says 'Expression discarded,' which is ambiguous about return values and side effects. It does not explain how the nine parameters are used, what the output looks like, or whether the tool is read-only or mutating.

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 short and front-loaded, which is good, but it is under-specified rather than appropriately concise. Two sentences do not provide enough structure to connect the stated purpose to the nine-parameter input schema.

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?

For a tool with nine parameters, no annotations, and no output schema, this description is completely inadequate for correct invocation. An agent cannot determine which parameter holds the expression, what the tool returns, or when it should be used.

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?

Although schema coverage is 100%, the description's core concept—an arithmetic expression—maps to no parameter in the schema. The per-parameter descriptions mention URLs, cities, JSON, and hostnames, which are unrelated to 'a+b style arithmetic,' so the description adds confusion rather than parameter clarity.

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 verb ('Evaluate') and a resource ('a+b style arithmetic'), but the input schema contains no arithmetic expression parameter. The phrase 'Expression discarded' also undermines the stated purpose, leaving an agent unsure whether evaluation actually happens or what input to provide.

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 gives no guidance about when to use calc-eval versus any of the sibling shape-check, validation, or fetch tools. It neither states a preferred context nor mentions alternatives or exclusions.

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