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

With no annotations, the description carries the transparency burden, but it only says 'Expression discarded,' which is fragmentary and does not align with the schema since there is no expression parameter. It does not say whether this is read-only, what side effects occur, whether auth is required, or what is returned. The mismatch between 'Evaluate' and 'discarded' leaves the tool's behavior genuinely unclear.

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, with little wasted wording. However, 'Expression discarded' is isolated and under-specified, and a one-line description is thin given a nine-parameter schema. It is concise but not effectively structured to support correct invocation.

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 dramatically incomplete. It does not specify which parameter carries the expression, what the output or return format is, or how it relates to sibling functionality. An agent cannot reliably construct a correct call from this definition.

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?

All nine parameters have schema descriptions (100% coverage), so the baseline is 3. The tool description adds no parameter-level meaning and never maps any schema field to the arithmetic expression it claims to evaluate. It neither improves nor degrades the schema's already high parameter coverage, though the mismatch is a concern.

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 an operation ('Evaluate a+b style arithmetic') and so says what the tool does at a high level. But the input schema exposes nine unrelated parameters and no arithmetic-expression field, making the stated purpose disconnected from how the tool is actually invoked. It also does not distinguish calc-eval from the many sibling shape-check/validation tools.

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 when-to-use, when-not-to-use, or alternative sibling tools are mentioned. With many shape-checking siblings such as validate-json, search-query-len, and domain-shape, an agent gets no basis for choosing calc-eval over them. The only implied hint is 'arithmetic', but no selection condition or exclusion is stated.

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